This standard provides a guide to the elements of a quality system for producing standard samples. It is applicable to producers of standard samples in various industries to establish and implement a quality system; it is also applicable to accreditation bodies, certification bodies and other relevant organizations to assess the quality system. This standard provides guidance for the production of both standard samples and certified standard samples as defined in GB/T 15000.2-1994. The requirements set forth in this standard are applicable to the quality system for the production of various standard samples, and this standard will also be used as part of the general quality assurance procedures of standard sample producers. The production of standard samples should be determined based on the application, the measurement methods for uniformity, stability and determination, and the limitations caused by the standard sample matrix. GB/T 15000.7-1997 Guidelines for Standard Samples (7) Quality system for the production of standard samples GB/T15000.7-1997 Standard download decompression password: www.bzxz.net
This standard provides guidance on the elements of a quality system for the production of standard samples. It is applicable to producers of standard samples in various industries for the establishment and implementation of a quality system; it is also applicable to accreditation bodies, certification bodies and other relevant organizations for the assessment of the quality system. This standard provides guidance for the production of both standard samples and certified standard samples as defined in GB/T 15000.2-1994. The requirements set out in this standard are applicable to the quality system for the production of various standard samples. This standard will also be used as part of the general quality assurance program of standard sample producers. The scope of application of this standard should be determined based on the application, the measurement methods for uniformity, stability and determination, and the limitations caused by the matrix of the standard sample.

GB/T15000.7—1997
This standard adopts the International Organization for Standardization's ISO Guide 34 Quality System Guide for Standard Sample Production. The equivalent conversion of standards follows the principles of authenticity, accuracy and operability. The content of ISO Guide 34, as described in the introduction of the guide, is to provide guidance for interpreting ISO/IEC Guide 25 and ISO9000 family standards. The formulation of this standard is particularly important for the research, development, production, sales and application of standard samples in my country. Since standard samples are a special product, they have different characteristics from other general products when determining their values. For enterprises that develop, produce and develop standard products, in order to establish their own quality system, in addition to referring to ISO/IEC Guide 25 and ISO9000 family standards, ISO Guide 34 should be used as the basic basis. This is the basic reason for us to adopt ISO Guide 34 as an equivalent. ISO/REMCO has developed or is developing seven international guidelines on reference samples: ISO Guide 6-1978 "Statement of reference samples in technical standards" ISO Guide 30-1992 "Terms and definitions of reference samples" ISO Guide 31-1981 "Contents of reference sample certificates" ISO Guide 32 [DIS] "Calibration of chemical analysis and the use of certified reference samples" ISO Guide 33-1989 "Application of certified reference samples" ISO Guide 34 [DIS] "Production of reference samples" ISO Guide 35-1989 "Value of reference samples - General and statistical principles" is a set of standards that provide comprehensive guidance for the development, manufacture, value, production and application of reference samples and certified reference samples. According to the needs, my country has adopted ISO Guide 6, ISO Guide 30, ISO Guide 31 and ISO Guide 35 in 1994, and has converted them into national standards:
General provisions for reference samples in technical standards Guide for reference samples (1)
GB/T 15000..1
Guidelines for Standard Samples (2) Terms and definitions used in standard samples GB/T15000.2
GB/T15000.3 Guidelines for Standard Samples (3) General principles and statistical methods for determining the value of standard samples GB/T15000.4 Guidelines for Standard Samples (4) Provisions on the content of standard sample certificates. The Secretariat of the National Technical Committee for Standard Samples will gradually convert all seven guidelines of the ISO in this regard into national standards according to needs.
Appendix A and Appendix B of this standard are indicative appendices. The unit proposing this standard is the National Technical Committee for Standard Samples. The unit responsible for this standard is the National Technical Committee for Standard Samples. The drafting unit of this standard is the Secretariat of the National Technical Committee for Standard Samples. The drafters of this standard are Chen Boyan, Ai Zheng, Gao Liangcai, Zhang Guangwei, Zhang Shuying and Pei Shan. GB/T15000.7—1997
ISO Foreword
ISO (National Technical Committee for Standard Samples) The International Organization for Standardization (ISO) is a worldwide federation of national standardization bodies (ISO member bodies). The work of developing international standards is usually done by the technical committees of ISO. If the member bodies are interested in the projects established by the basic technical committees, they have the right to participate in the work of the committees. International organizations (official or unofficial) that maintain contact with ISO can also participate in the relevant work. In the field of electrotechnical standardization, ISO maintains a close cooperative relationship with the International Electrotechnical Commission (IEC). ISO guidelines are basically intended for internal use by ISO committees or to guide member bodies to deal with certain contents that cannot be the subject of international standards.
ISO Guide 34 was developed by the ISO Standard Sample Committee and approved by ISO member bodies. GB/T15000.71997
The use of standard samples makes it possible for laboratories engaged in testing, analysis and measurement to communicate the measured values ​​or assignments to each other. Standard samples are widely used in the calibration of measuring equipment and the evaluation or confirmation of the effectiveness of measurement procedures. In some cases, the application of standard samples allows characteristics to be conveniently expressed in arbitrary units.
The number of producers of standard samples is increasing day by day. In order to ensure the quality of standard samples, it is now a basic requirement to provide proof of their scientific and technical capabilities. In the field of science and technology, due to the increasing requirements for data accuracy and reliability and the precision of measuring equipment, some original standard samples may not meet these more stringent requirements, so it is required to produce new standard samples of higher quality to meet their needs. For the producers of reference materials, it is not only necessary for them to provide information about the reference materials in the form of reports, certificates and instructions, but also they must demonstrate that they have sufficient capabilities to produce reference materials of acceptable quality by establishing and implementing a quality assurance system. This standard provides guidance on the interpretation of ISO/IEC Guide 25 and the ISO 9000 family of standards, that is, it provides a system that can prove that "the production of reference materials is in accordance with the requirements of the ISO 9000 family of standards, and the calibration process complies with the requirements of ISO/IEC Guide 25": 1 Scope National Standard of the People's Republic of China Guide for the work of reference materials (7) Quality system for the production of reference materials GB/T 15000.7--1997 1.1 This standard provides guidance on the elements of a quality system for the production of reference materials. It is applicable to the establishment and implementation of a quality system by producers of reference materials in various industries, and is also applicable to the assessment of the quality system by accreditation bodies, certification bodies and other relevant organizations. This standard provides guidance for the production of both standard samples and certified standard samples as defined in GB/T15000.2-1994. 1.2 The requirements set forth in this standard apply to the quality system for the production of various standard samples, and this standard will also be used as part of the general quality assurance program of standard sample producers. The producers of standard samples should determine the scope of application of this standard based on the application conditions, as well as the measurement methods in the process of homogeneity, stability and determination, and the limitations caused by the matrix of the standard samples. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. At the time of publication of this standard, the versions shown are valid. All standards are subject to revision, so parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T6583-94 Quality Management and Quality Assurance Terms (idtIS) 8402:1994) GB/T 15000.2-94 Standard Sample Working Guidelines (2) Common Terms and Definitions for Standard Samples GB/T15000.3-94 Standard Sample Working Guidelines (3) General Sources and Statistical Methods for Determining the Value of Standard Samples GB/T15000.4-94 Standard Sample Working Guidelines (4) Provisions on the Contents of Standard Sample Certificates GB/T19000-94 Quality Management and Quality Assurance Standards (idtISO9000.1994) GB/T19022.1-94 Quality Assurance Requirements for Measuring Equipment Part - Metrological Confirmation System for Measuring Equipment (idtIS0 10012-1:1992)
ISO/IEC Guide 2:1991 General terms and definitions for standardization and related activities ISO/IEC Guide 25, 1990 General requirements for the competence of calibration and testing laboratories VIM:1993 International General Terms of Reference for Basic Measurement - Guide to the Expression of Uncertainty in Measurement, First Edition, 1993 3 Definitions
This standard refers to the definitions in ISO/IEC Guide 2, ISO/IEC Guide 25, GB/T 6583-1994, GB/T 15000.2—1994 and VIM and the following definitions:
3.1 Standard sample producer
A technically competent organization (organization or company, public or private) that can produce standard samples in accordance with the requirements of GB/T 15000.3 and GB/T 15000.4.
Guohao Technical Supervision Bureau 1997-11-11 oil
1998-05-01 implementation
3.2 Co-authorship
G1/T 15000.71997
Technically competent institutions (organizations or companies, public or private) that manufacture or value standard samples (certified standard samples) for standard sample producers in the form of contracts or on their own. 4 Organizational requirements
4.1 Environmental conditions
The standard sample producer shall ensure that the test facilities, calibration and measurement sites, material preparation and packaging sites and their energy, lighting, temperature, humidity, air pressure and ventilation are suitable for material preparation, packaging and calibration and measurement operations. Where necessary, environmental conditions should include sensitivity, vibration protection, protection against atmospheric dust and microbial contamination, magnetic fields and electromagnetic radiation. The standard sample producer should also ensure that any collaborator involved in any production process meets these requirements. For example: Packaging of cement materials requires low humidity in the site: When preparing materials for the determination of trace lead, there are special cleanliness requirements in the workplace to prevent contamination by lead particles emitted into the atmosphere by automobiles. For trace plate analysis, clean conditions may be required. Where necessary, such as when handling pesticides and III, necessary measures to protect health, safety and the environment need to be taken. Appropriate temperature control facilities may also be required when producing certain types of standard companion products. Where necessary, the environment in which these activities are carried out should be monitored, controlled and recorded to ensure that there is no adverse effect on the process and results. 4.2 Quality policy and quality system
4.2.1 Quality policy
The producers of standard samples shall define their quality policy, objectives and commitments and document them to ensure and maintain the quality of all aspects of the production of standard samples, including the quality of materials (such as homogeneity and stability), the quality of values ​​(such as calibration of equipment and validation of measurement methods), the determination of sustainability (such as the application of appropriate statistical procedures) and the handling, storage and transportation of materials. Where necessary, the quality policy shall include the confirmation of the laboratory space capability, and the laboratories participating in these value studies shall be competent in their respective measurement fields. In principle, the policy shall include mutual contact and cooperation with the corresponding industries in the testing technology community to avoid working alone. The policy shall also include: the production of standard samples in accordance with the requirements of GB/T15000.2, and the evaluation and documentation of their characteristic values ​​in accordance with the requirements of GB/T15000.3 and GB/T15000.4. In order for users to fully understand the application type of a certain standard sample, the producer of the standard sample shall state the intended use of such a standard sample.
4.2.2 Quality system
The standard sample producer shall establish and maintain a documented quality system, which shall be appropriate to the type, scope and quantity of standard sample production to ensure that the standard samples produced meet the specified requirements. In addition to complying with the general requirements specified in ISOO/IEC Guide 25:1990 and GB/T19000, the quality system established by the standard sample producer shall include the following: a) Ensure the planning of various relevant selections (such as the concentration range and particle size of candidate standard samples); b) Preparation procedures!
) Obtaining the homogeneity of standard samples;
d) Stability assessment of standard samples;
e) Procedures for the determination process;
f) Obtaining traceability to national or international measurement standards; g) Giving out characteristic values, including certificates or instructions in accordance with GB/T15000.4-1994! h) Ensure and arrange appropriate storage facilities:
i) Appropriate labeling, packaging facilities, packaging and distribution procedures and arrangements for sales and service operations. 4.3 Management, personnel and training
When conditions permit, the production of standard samples should be undertaken by an organization with experience in producing specific standard samples (and related materials) and having experience in measuring the values ​​of specified characteristics.
The standard sample producer should be equipped with management personnel. These personnel should have the necessary authority, resources and technical capabilities to perform their duties. These management personnel may have the necessary professional qualifications or recognized qualifications based on relevant work experience. The measurement of the required characteristics GE/T 15000.7—1997
should be completed by technically competent management personnel or under their supervision. The standards producer should specify the minimum qualifications and experience that must be possessed by personnel in key positions within its organization. The standards producer should have adequate staff who have the education, training, technical knowledge and experience required to undertake the functions in question (e.g., a person engaged in thermal expansion measurements should have a degree or appropriate level of qualification and should have experience working with experts in this field and making measurements to an equivalent level of accuracy). Where necessary, the standards producer should also provide additional training to personnel to ensure that they are competent to perform the measurements, the operation of equipment, and other activities that directly affect quality. Measures should be taken to objectively assess the competence acquired by personnel during training. Consideration should be given to the need for periodic retraining of personnel (e.g., when a measurement method or measurement technique is not frequently used, the standards producer should arrange for retraining of personnel as appropriate). The standards producer should maintain records of the latest training received by each member of the staff, including that their competence to perform specific types of material preparation and measurements has been assessed. 4.4 Collaborators
When the producer of standard samples is engaged in the production or assignment of standards on the basis of collaboration between laboratories, the producer should be able to prove that its collaborators have sufficient experience and that their products or results meet the quality requirements. When assessing the capabilities of collaborators, collaborators may be required to provide detailed past experience in this field and to recognize the validity of the results that can be compared with the relevant experience. That is, before issuing any sample of a candidate standard sample, materials with well-assigned characteristic values ​​can be issued to verify its capabilities. When conducting experiments, collaborators that have been recognized in ISO/IFC Guide 25 or have been certified in other activities in the GB/T19000 family of standards must usually be selected. Under this condition, the producer of standard samples may not have laboratory facilities, but should ensure that all scientific work performed by collaborators that affects the assignment of standard sample characteristics meets the requirements of the purpose. The producer of standard samples should ensure that the details of all methods, results and operating procedures of collaborators are appropriate and ensure that a list or database of all collaborators is maintained. 4.5 Handling and storage of materials
The standard sample producer shall identify, preserve and distinguish the standard samples and candidate materials from other chemicals and samples throughout the process from preparation to release of the standard samples. The standard sample producer shall ensure that all standard samples are packaged in a suitable manner (vacuum, anhydrous or inert gas packaging is required when necessary). Provide safe storage locations/warehouses to prevent damage or deterioration of any items or materials during both the calibration and release processes. Appropriate management methods should be specified for approval of receipt and delivery from these locations. All stored/stocked items and materials should be evaluated regularly to detect whether the quality of the standard samples has deteriorated. The standard sample producer should control the packaging and marking processes to ensure that they meet transportation and safety requirements. In particular, for materials that require continuous storage in cold storage, materials that cannot be exposed to X-rays, materials that cannot be subjected to vibration or impact, the release process may cause some problems and should be given special attention. For most chemical materials, it is best to use sealed packaging to avoid major contamination (i.e. contamination by fuel vapor or engine exhaust gas). The standard sample label shall be affixed to each unit package of the product and shall be designed to ensure that it remains identifiable and intact throughout the validity period of the material. The label shall indicate the material, production sample, batch and classification number and other necessary information to uniquely identify and reference the material. Where necessary, include instructions or certificates. The standard sample producer shall make arrangements to maintain the integrity of each standard sample throughout the production process. When legal provisions are made, this integrity protection shall continue until delivery at the destination. 4.6 Records and Reports
The standard sample producer shall establish and maintain a record keeping procedure that is appropriate to its specific environment and in accordance with any applicable regulations. The standard sample producer shall arrange for all independent measurement observations, necessary calculations and derived data calibration records and development reports to be retained for a period of time until these records are no longer required for reference. Where necessary, the results of each calibration or measurement (or series of calibrations or measurements) performed by the standard sample producer and its collaborators shall be reported in a precise, clear, unaltered, non-translated and objective manner as specified in the instructions for the calibration and measurement methods. The back of the report should generally include the measurement and calibration results, as well as the necessary information for interpreting these results and an overview of the methods used (Note: This is an internal report of the standard sample producer and should not be confused with the value report of the certified standard sample. 4. Post-issuance service
GB/T 15000.7--1997
The standard sample producer should establish and maintain a documented procedure to ensure that corrective measures can be taken whenever it is found that the product does not meet the specified requirements. Any changes (such as changes in procedures and data) should be recorded. If the given characteristic value changes during the validity period of the standard sample (for example, due to the results of the attached measurement study),All purchasers of standard samples should be informed.
As an integral part of these procedures, the standard sample producer should maintain a mailing list of each "standard sample purchaser" in order to inform them of any issues regarding the validity of a certain standard sample property value that the user needs to know. The standard sample producer should also provide users with guiding advisory services (including appeal procedures) and technical services. 5 Production Control
5.1 Planning
The standard sample producer shall determine and design those processes that have a direct impact on the quality of standard sample production and ensure that these processes are carried out under controlled conditions.
The organizational and technical inputs of the cooperating parties should be determined, and the required information should be documented and reviewed regularly. A body (i.e., management/technical advisory group) should be established to provide advice on the planning of the production process. These recommendations include production, construction, Establish a monitoring system (to ensure timeliness and quality at each stage of production), as well as an assessment procedure to track and evaluate the production process. In order to simulate the test process as closely as possible, natural standard samples should have the same or slightly the same matrix as the routine test materials. They should not be contaminated during processing or preparation, which would artificially increase the content of certain elements (whose concentrations will be assessed) in natural standard samples. For example, for natural standard samples with a high cobalt content, consideration should be given to avoiding the use of grinders/mixers made of stainless steel to grind/mix the materials. If possible, the species (morphology, composition, etc.) of the analyte should be similar to that in the matrix of the routine test materials. When appropriate, the standard sample production report should have procedures and service facilities for the following tasks: a) Select materials: b) Maintain a suitable environment; c) Maintain a suitable environment; ) Preparation of materials:
d) Measurement/qualification:
e) Verification/validity of equipment/measurement or method: f) Assess the uniformity of material production:
8) Assess the stability and ductility of materials;
h) Organize inter-laboratory (comparison) studies with other laboratories: i) Give characteristic values ​​based on measurement results:
) Assess the uncertainty of the assigned characteristic values; k) Ensure appropriate storage facilities and conditions: 1) Ensure appropriate packaging facilities:
m) Ensure appropriate transportation planning arrangements;
Ensure appropriate after-sales service.
The manufacturer of standard samples should determine the necessary inspection procedures to ensure the quality of each stage in the production of standard samples, and assign appropriate personnel and provide necessary resources for these activities. These activities include each production Inspection, testing, monitoring, etc. during the stages. 5.2 Material preparation
The standard sample producer should establish a preparation procedure to determine whether the item or material meets its intended use. These procedures include the following: bzxZ.net
a) Qualitative analysis to verify the type of material:
b) Machining, grinding, mixing, sieving and reducing (i.e. dividing into representative samples);
d) Cleaning the sample container:
GE/T15000.71997
e) Drying (including cold drying or sublimation drying) and sterilization:
f) Filling the batch into representative samples (e.g. bottling, etc.);
h) Stability testing over the entire range of conditions that may have an adverse effect on the standard sample being produced. For example, different levels of humidity, temperature, lighting, magnetic field, etc. The standard sample producer should be able to prove that the candidate standard sample is sufficiently homogeneous. That is, the difference between the measured values ​​of representative samples must be less than the uncertainty of the given characteristic value. However, it should be noted that sometimes the most easily available material may not be sufficiently homogeneous. Therefore, as long as this is properly taken into account when evaluating the uncertainty of the characteristic value, such material can still be used as a standard sample. 5.3 Homogeneity and stability assessment
A certain number of representative samples are randomly selected from the candidate standard samples in a statistical manner to assess the homogeneity, which should be based on the requirements of GB/T15000.3. For those standard samples that are expected to be uniform on a physical basis, the main purpose of the homogeneity test is to detect unexpected problems. For example, different contamination when packaged into independent units, or incomplete dissolution or non-equilibrium of the analyte in the additive (which may cause continuous changes in concentration). For these types of examples, such as the separation of coarse and fine particles in a powdered rice, it is often better to use systematic sampling than random sampling to detect its heterogeneity. Systematic sampling is a method such as in a continuous production process, every 50 samples are produced. , take one sample from it, or, if sub-batches can be identified, sample each sub-batch at specified intervals.
Statistical trend analysis is also helpful in detecting inhomogeneities. If the material is produced in batches, the equivalence of the batches must be tested (or each batch must be assigned a separate characteristic value). Unless stability studies indicate that the material should not be stored in bulk form, the assessment should be carried out after the material is packaged in its final form. In some cases, such as before bottling, it may be necessary to test the uniformity of intermediate products. Where necessary, the characteristic values ​​to be assessed should be measured regularly, preferably under storage conditions before the material is released to the user. In order to provide recommendations on storage location and life (and thus give an appropriate storage Shelf life/expiration date), the effects of light efficacy, humidity, and thermal efficiency time on it must be quantitatively given. Stability tests can only be carried out after sufficient uniformity has been demonstrated: any product, as long as it is not smaller than the sample used in the uniformity test, can be considered representative. There are no restrictions on the number of samples required and the method of random selection. However, the deviation of the measurement results depends on the repeatability and medium precision of the measurement technology, so repeated tests should be carried out. When standard samples are used to calibrate methods that require small amounts of samples (for example, graphite furnace atomic absorption spectrometry and inductively coupled plasma spectrometry only require 10g to 100g of samples), it is necessary to evaluate the uniformity of standard samples of the same size and determine the samples used to determine the uniformity of the standard samples. The manufacturer of the standard sample shall provide the stability of the assigned characteristic values. If necessary, after the standard sample is set, the stability of the assigned characteristic values ​​needs to be evaluated regularly to confirm that all values ​​remain unchanged from production to final use. Wherever appropriate, the manufacturer of the standard sample shall provide the validity period of the produced standard sample in accordance with the requirements of GB/T15000.3. The validity period is determined based on the initial and current stability studies. In some cases, it can also be understood that the validity period starts from the day of transportation. However, in all appropriate cases, the manufacturer should conduct stability studies in use.
The manufacturer of the standard sample shall provide details of the uniformity stability study conducted in accordance with the requirements of GB/T15000.3. 5.4 Measurement method
The manufacturer of the standard sample adopts a documented measurement method or procedure, which includes the determination of the preparation, sampling, handling, preservation, packaging, transportation, evaluation of measurement uncertainty and analysis of measurement data for different analyses, calibrations, measurements and related activities within its scope of responsibility. Activities involving accuracy requirements shall comply with the accuracy requirements of the reference material and with the requirements of the standard specification associated with the test.
The measurement method developed internally by the reference material producer or author shall be approved and recognized before application (e.g. by the management/technical advisory group or the licensee). This method shall include a well-developed, clear and precise description of the conditions and procedures necessary to correctly measure the value of the property to be measured at a level of accuracy appropriate to the intended use of the reference material. In some cases, the value of the reference material depends on the characteristics of the method, such as the metal that can be released, pH value or flash point. When sampling is an integral part of the measurement method (e.g. subsampling from a batch of material to take out a representative amount of material GB/T 15000.7—1997
), the reference material producer shall use documented procedures and appropriate statistical techniques to collect and test. 5.5 Measuring equipment
When necessary, the measuring equipment used in the production of reference materials shall be appropriately calibrated or verified and maintained using documented procedures, and the results shall be recorded. The performance of the measuring equipment should be checked regularly (e.g., response, stability, linearity, resolution, measurement binning, repeatability, separation efficiency, etc.) to ensure that the equipment is working properly. The frequency of such performance checks should be determined based on experience and the type of equipment and the performance of the equipment in the past. According to the requirements of GB/T19022.1, the interval between each check should be less than the time when the drift of the equipment exceeds the tolerance. When any measuring equipment has a suspicious result due to overload or misoperation, or the equipment is found to be defective through verification or other methods.It should be identified and removed from use, and stored in a specified place as far as possible until it is repaired and calibrated, verified or tested to meet the requirements. The producer of the standard sample should review the impact of the results obtained using this equipment, especially the deviation of the calibration, the relevant results and the tolerance of the results. When the results are significantly in error, the producer of the standard sample should verify the results, identify the reasons and take corrective measures. The review and verification/corrective measures should be recorded and preserved. Equipment (including measurement standards) used in the calibration of equipment used to produce standard samples or the approval of measurement methods should be marked with its calibration status and validity period by labels, signs or other identifiable methods. These requirements also apply to reagents used in chemical analysis. All measurement bases and test equipment that affect the accuracy or validity of calibration or measurement should be calibrated or verified before being put into use. The producer of standard samples and collaborators should develop a calibration and verification plan for measurement and test equipment. A comprehensive plan for equipment calibration or verification should be developed and implemented to ensure that measurements made by the producer of standard samples can be traced back to national or international measurement standards through a continuous chain of comparisons regardless of where they are used. Where necessary, the calibration certificate for the measuring instrument should briefly state the traceability to the national measurement standard and provide the measurement result and the associated measurement uncertainty. 5.6 Verification of traceability and validity Although it is usually possible to trace the individual characteristic values ​​of a standard sample to the corresponding SI base units through a series of consecutive calibrations, it is more difficult to obtain such traceability in a purely scientific sense when the chemical composition of complex materials (e.g. molar concentrations, molar ratios, mass fractions and mass concentrations) is considered. In these cases, the main influence on the uncertainty of the measurement result is not due to the fact that the measured values ​​of mass, volume, current or "amount of substance" cannot be traced back to the corresponding SI units of kilogram, meter, ampere or mole. Instead, it comes from the measurement method adopted, the selectivity of the procedure limit. Because in many cases the measured components are often shared with other chemically similar components, the standard sample producer should provide written evidence of the traceability of the measurement when traceability to a national or international measurement standard is possible. When this is not possible, the standard sample producer should provide satisfactory proof that its results are related to other results. This proof can be obtained by extensive evaluation of the measurement process or by comparison with known and recognized national certified standards or international certified standards. Ideally, the latter method uses certified standards that are themselves sufficiently traceable. For a more comprehensive discussion of the requirements and concepts of traceability, see Appendix A (Informative Appendix). 5.7 Data Evaluation
When computers or computer-controlled systems are used to collect, process, evaluate, record, report, store or retrieve calibration or test data, the reference material manufacturer shall ensure that: a) Computer software (especially internally developed software) is validated to meet the application requirements when possible; 1) A procedure is established and implemented to protect the integrity of data. The procedure should include (but not be limited to) the integrity of data input, acquisition, data storage, data transmission and data processing; c) Equipment is retroactively maintained to ensure that it has qualified functions and an environmental condition and working conditions that maintain data integrity are provided; d) Procedures are established and implemented to protect data security. The procedures should include preventing unauthorized access and modification of computer records. Where possible, hard copies of all computer records should also be retained to overcome the difficulties caused by comparing new data with data obtained using outdated or superseded software.
5.8 Value determination method
GB/T15000.3-1994 has several technically valid methods for determining the value of standard samples, including the following methods: a) A small organization (which may include several independent laboratories) uses a single authoritative method to avoid measurement! GB/T 15000.7-1997
b) An organization uses two or more independent standard methods to measure. These methods should have a smaller uncertainty for the intended use of the standard sample. This method of determining the value should be confirmed by other measurement methods or laboratories; c) Inter-laboratory collaborative measurement by multiple qualified organizations. The premise is that the accuracy of the measurement method used is confirmed, and its uncertainty is evaluated and considered acceptable; d) Only one specific way to evaluate the characteristic value is given, and the research between laboratories selects a specific measurement method according to this way. According to the type of standard sample, the intended use, the capabilities of the participating laboratories, and the level of the method, an appropriate method of determination is sought. The standard sample producer should be able to ensure that the value determination study complies with the requirements of GB/T15000.3-1994. Only when the equipment and technology can guarantee the traceability to the International System of Units (SI) system, can a single authoritative method be used for value determination. The more commonly used method is: the laboratories of several cooperating units independently use more than one measurement method to carry out the value determination work. The characteristic value evaluated by this method is more reliable. Generally speaking, the standard sample producer should appropriately select appropriate partners to ensure that the objective needs of the production process are met. If necessary, it includes ensuring that the quality of the standard samples being produced meets the requirements specified by the producer and the user. 5.9 Determination of characteristic values
5.9.1 General
The most important work in determining the characteristic values ​​of the produced standard samples is to assess their uncertainty. When assessing the desired characteristic values, the standard sample producer cannot rely entirely on statistical analysis of the value determination data. Abnormal values ​​cannot be eliminated based on purely statistical evidence before they have been fully studied and the reasons for their occurrence have been clarified. On the contrary, in some cases, other methods may be applicable.
When using several methods to calibrate a standard sample, if the results obtained are quite different, it may be difficult to determine the value, so it is not appropriate to express the characteristic value as an average value. In this case, it is important that the standard sample producer and collaborator should have extensive experience in the application of different methods and be able to give more or less "weight" to the results obtained by a specific measurement method. For example, the average values ​​of two (or more) measurement methods may be statistically different, but the results obtained by the two methods are consistent within the uncertainty of each method. In this case, the results can be weighted according to the inverse of the variance of each method; in addition, when the results obtained by various measurement methods are incompatible, the characteristic value can be determined separately according to the method used. That is, the characteristic value is determined according to the above-mentioned method of "only giving a specific way to evaluate the characteristic value".
When necessary, the standard sample producer shall issue a statement or certificate to convey information about the standard sample. These certificates or instructions shall provide users with information about the characteristic value, its meaning, uncertainty at the specified confidence level, and the validity period of the standard sample. The certificate or instruction should also include information on how users use the standard sample and possible problems during use. The content of the certificate or instruction should comply with the provisions of ISO Guide 31. When determining the required standard sample characteristic value, the standard sample producer should consider establishing an independent expert group whose responsibility is to check whether all work, data and documents are consistent with H. The standard sample producer also needs to prove the traceability of the characteristic value in accordance with the requirements of GB/T15000.3. 5. 9.2 Uncertainty assessment
Each measurement carries its own uncertainty (see Guidelines for expressing uncertainty). All known and correctable systematic errors should be corrected and assessed, and the uncertainty caused by these corrections themselves should also be assessed. The uncertainty caused by possible unknown systematic errors should also be assessed based on the results of mutual comparison. Calculations and data transmissions should be properly checked, and the standard sample producer should use appropriate statistical techniques to verify the credibility of all data related to the required characteristic values. The uncertainty of a given characteristic value should be assessed. This assessment should always be based on a combination of uncertainties. These three uncertainties are the uncertainty caused by correcting known systematic errors, the uncertainty caused by possible systematic errors, and the uncertainty caused by random errors in repeated observations. Under ideal conditions, the latter should account for a smaller proportion of the uncertainty of a specific characteristic value. In some cases, it may be necessary to assess the uncertainty based on the experience of the measurement base methods and the reliability of these methods. At this time, it is necessary to explain the justification for adopting this assessment method. A1 Concept of traceability
GB/T15000.7—1997
Appendix A
(Informative Appendix)
Traceability of Standard Sample Property Values
The term “traceability” is used more and more frequently to describe the reliability of measurements. However, its exact meaning is not clear. Generally speaking, traceability means "a continuous path (with a certain uncertainty) to some higher level of accuracy or authority". In an absolute sense, it is the path to the SI system of units and their derived units. Currently, in the VIM, the term is usually defined as "the property of a measurement result being able to be related to appropriate standards, usually national or international standards, through a continuous chain of comparisons." In other words, when a measurement result is described as traceable, it is important to state that this "appropriate standard" is traceable, that is, this "appropriate standard" can be traced back to an SI base unit (such as the ampere), a dimensionless mass fraction, a defined scale (such as pH and hardness), or a method described in a national or international measurement standard. When determining the value of a standard sample of a physical property, the determination of traceability can generally be linked to the base unit of the SI by performing a subsequent calibration of the instrument. For example, specific heat capacity standards are measured in terms of energy, temperature and mass, all of which can be traced back to the SI or to a national metrology laboratory using instruments calibrated by national metrology laboratories. However, when standards for chemical composition are measured, traceability is often more difficult to establish. For example, while there is no difficulty in weighing a sample on a precision balance using a traceable calibration code, the analyte can rarely be determined by weighing. Often it is only determined by actual measurement on an analytical instrument after a number of quantitative processes such as sampling, dissolution, extraction and separation by chromatography or more traditional wet chemical methods. Any or all of these processes are links in the traceability chain and have their own uncertainties, so the chemist must assess the efficiency of each process in retaining the analyte completely (either unchanged or converted to a compound with which it has an ideal relationship) and in separating it from substances that interfere with the final measurement. When the property value is expressed as an amount of substance, the chemist faces a special problem. Because balances are widely used in chemical experiments, the characteristic values ​​of most certified standard samples of chemical components are expressed in "mass ratio" or "mass concentration" rather than in moles to express "amount of substance". However, mass arithmetic is very similar to molar arithmetic, so the producer of standard samples only needs to prove that the method used is reliable for determining a specific analysis in a specific sample. For example, the units used are grams of lead per gram of blood or grams of animal tissue.
A2 Determination of the value of standard samples
The ISO Guide 35 used in this standard recognizes the following methods for determining the value of standard samples: a) measurement by a single, authoritative method in a single laboratory, measurement by one or more independent standard methods in a laboratory; b) measurement by a network of recognized laboratories using one or more confirmed methods. Authoritative methods are those whose characteristic values ​​can be directly measured in terms of basic units of measurement or can be directly related to natural units through physical or chemical theories expressed in accurate mathematical formulas. Therefore, the term also includes chemical analysis methods whose test results may not necessarily meet the requirements of VIM. Even if such high-quality analytical methods are available, they are required to be independently performed by two or more analysts, and preferably with unloaded experimental equipment. The premise of inter-laboratory testing is that there are some laboratories of the same level, the measurement methods used are considered to be independently recognized, and the differences between the results obtained are statistical in nature and can be treated with purely statistical procedures. Although this method is often used for value determination, it often only reflects the comparability between experiments and may lead to the recognition of incorrect values, especially when statistical treatment methods are considered to be more important than chemical knowledge and judgment. This problem is prone to occur. A sub-procedure of this procedure is to perform analysis using a specific method.
GB/T 15000.7 1997
Thus, the scope of traceability of reference materials can range from "a close comparative chain of traceability to SI base units through instrument calibration" to "application of a well-established standard method". In each of the above cases, the reference material producer needs to investigate how the relevant principles apply. In particular, for certified reference materials, it is important that their certificate include a statement of traceability and a brief description of the principles and procedures on which the characteristic values ​​(including uncertainties) are based. If there is no value for this additional information, it is generally not considered a certified reference material. A3 Examples
A3.1 to A3.6 examine the establishment of some of the main types of chemical reference materials.1 The problem of traceability of standard values. A3.1 Mixed gases||tt ||The value of this type of standard sample is the easiest to trace among all chemical composition standard samples. It can be obtained by comparing it with the reference mixed gas prepared by the re-disk method (through gas chromatography or other analytical methods). The traceability of the reference standard is established by mass traceability to national mass standards and the atomic/molecular mass basis of the components and by the purity of the components. The stability of the mixed gas in the gas cylinder must also be determined, which is achieved by regularly analyzing it and comparing the long-term stored mixed gas with the newly prepared mixed gas.
A3.2 alloy
The number of this type of standard samples may be more than any other type of standard samples. Most of these standard samples use published methods to implement The values ​​are determined by interlaboratory comparison procedures. It is important, however, that the reliability of these methods has been fully established. The analytical procedure generally involves dissolving the alloy prior to the analytical procedure. When possible errors due to incomplete knowledge of the alloy composition cannot be eliminated, important evidence of the validity of the analytical method can be provided by the analysis of a synthetic solution prepared from a spectroscopically pure metal and similar in composition to the alloy solution to be tested.
The validity of the analytical method for the nonmetallic components of the alloy can be confirmed by the use of compounds of high purity and known chemical identifiable properties, for example, calcium carbonate for the determination of carbon content, potassium dihydrogen phosphate for the determination of phosphorus content, and metal oxides for the determination of oxygen. A3.3: Pure Chemical Compounds
Except for some compounds that can be determined by precise titration Except for substances for which the method of determination is available, it is usually not possible to determine the major component with sufficient accuracy to obtain a meaningful purity value. Methods based on melting characteristics (e.g. scanning calorimetry) measure all the properties in a substance, but require that the substance be stable at its melting point and are reliable only when the system is ideal and the impurities do not form solids in the presence of the major component. When no direct method is available, the analytical chemist must use as many techniques as possible to find ways to separate and determine all the individual impurities. Chromatography is the most useful method for organic chemicals because of the wide variety of separation and detection systems available. However, it must be recognized that it cannot solve the problem of resolving impurities that have chemical properties similar to those of the major component. A producer of pure chemicals must also recognize that proving the identity of a chemical is as important as proving the purity of the compound. It is sometimes impossible to publish chemical publications without information on compounds whose chemical structures have been misidentified; therefore, evidence of the identity of a substance is always an integral part of the traceability of a purity certificate.
A3.4 Trace elements in organic and inorganic substances (including water) The application of isotope desorption mass spectrometry (IDMS) overcomes many of the difficulties associated with the determination of trace elements. IDMS does not require quantitative separation of the sample to compare the ratio of the isotope atomic number of different substances to obtain the required results. In theory, it can be directly derived to the mole. Adding isotopes of the analyte elements to the sample and then homogenizing the isotopes, the mass spectrometry method can be used to determine the material ratio of the analyte and the tracer, and the "matrix effect" can be largely eliminated because the "matrix effect" has the same effect on the analyte and the tracer.
A3.5 Organic matrices and organic compounds in water. The most problematic standard samples for establishing traceability are trace pollutants in organic matrices (such as chlorinated biphenyls and hexachlorobenzene in animal fat), pollutants in water (such as pesticides in tap water), and clinical chemistry analysis (such as cholesterol in blood). Since IDMS requires that the tracer used should show extremely similar properties to the analyte during separation and extraction (of course, this is difficult to achieve), DMS cannot be completely satisfactory. A3.6 For other chemically stable compounds6. Other chemically stable compounds6. Other chemically stable compoundsor traceability to a national metrology laboratory. However, when determining the value of a standard sample of a chemical component, it is often more difficult to establish traceability. For example, although there is no difficulty in weighing a sample on a precision balance using a traceable and calibrated code, the analyte can rarely be determined by weighing. Often it is only after a quantitative process such as sampling, dissolution, extraction and chromatography, or more traditional wet chemical separation, that the actual measurement of the analytical instrument is concluded. Any or all of the above processes are links in the traceability chain and have their own uncertainties, so the chemist must assess the efficiency of each process in completely retaining the analyte (which may be retained unchanged or converted into another compound with which it has an ideal ratio) and in separating it from substances that interfere with the final measurement. When the characteristic value is expressed as an amount of substance, the chemist faces a special problem. Because balances are widely used in chemical experiments, the characteristic values ​​of most certified standard samples of chemical components are expressed in "mass ratio" or "mass concentration" rather than in moles to express "amount of substance". However, mass arithmetic is very similar to molar arithmetic, so the producer of standard samples only needs to prove that the method used is reliable for determining a specific analysis in a specific sample. For example, the units used are grams of lead per gram of blood or grams of animal tissue.
A2 Determination of the value of standard samples
The ISO Guide 35 used in this standard recognizes the following methods for determining the value of standard samples: a) measurement by a single, authoritative method in a single laboratory, measurement by one or more independent standard methods in a laboratory; b) measurement by a network of recognized laboratories using one or more confirmed methods. Authoritative methods are those whose characteristic values ​​can be directly measured in terms of basic units of measurement or can be directly related to natural units through physical or chemical theories expressed in accurate mathematical formulas. Therefore, the term also includes chemical analysis methods whose test results may not necessarily meet the requirements of VIM. Even if such high-quality analytical methods are available, they are required to be independently performed by two or more analysts, and preferably with unloaded experimental equipment. The premise of inter-laboratory testing is that there are some laboratories of the same level, the measurement methods used are considered to be independently recognized, and the differences between the results obtained are statistical in nature and can be treated with purely statistical procedures. Although this method is often used for value determination, it often only reflects the comparability between experiments and may lead to the recognition of incorrect values, especially when statistical treatment methods are considered to be more important than chemical knowledge and judgment. This problem is prone to occur. A sub-procedure of this procedure is to perform analysis using a specific method.
GB/T 15000.7 1997
Thus, the scope of traceability of reference materials can range from "a close comparative chain of traceability to SI base units through instrument calibration" to "application of a well-established standard method". In each of the above cases, the reference material producer needs to investigate how the relevant principles apply. In particular, for certified reference materials, it is important that their certificate include a statement of traceability and a brief description of the principles and procedures on which the characteristic values ​​(including uncertainties) are based. If there is no value for this additional information, it is generally not considered a certified reference material. A3 Examples
A3.1 to A3.6 examine the establishment of some of the main types of chemical reference materials.1 The problem of traceability of standard values. A3.1 Mixed gases||tt ||The value of this type of standard sample is the easiest to trace among all chemical composition standard samples. It can be obtained by comparing it with the reference mixed gas prepared by the re-disk method (through gas chromatography or other analytical methods). The traceability of the reference standard is established by mass traceability to national mass standards and the atomic/molecular mass basis of the components and by the purity of the components. The stability of the mixed gas in the gas cylinder must also be determined, which is achieved by regularly analyzing it and comparing the long-term stored mixed gas with the newly prepared mixed gas.
A3.2 alloy
The number of this type of standard samples may be more than any other type of standard samples. Most of these standard samples use published methods to implement The values ​​are determined by interlaboratory comparison procedures. It is important, however, that the reliability of these methods has been fully established. The analytical procedure generally involves dissolving the alloy prior to the analytical procedure. When possible errors due to incomplete knowledge of the alloy composition cannot be eliminated, important evidence of the validity of the analytical method can be provided by the analysis of a synthetic solution prepared from a spectroscopically pure metal and similar in composition to the alloy solution to be tested.
The validity of the analytical method for the nonmetallic components of the alloy can be confirmed by the use of compounds of high purity and known chemical identifiable properties, for example, calcium carbonate for the determination of carbon content, potassium dihydrogen phosphate for the determination of phosphorus content, and metal oxides for the determination of oxygen. A3.3: Pure Chemical Compounds
Except for some compounds that can be determined by precise titration Except for substances for which the method of determination is available, it is usually not possible to determine the major component with sufficient accuracy to obtain a meaningful purity value. Methods based on melting characteristics (e.g. scanning calorimetry) measure all the properties in a substance, but require that the substance be stable at its melting point and are reliable only when the system is ideal and the impurities do not form solids in the presence of the major component. When no direct method is available, the analytical chemist must use as many techniques as possible to find ways to separate and determine all the individual impurities. Chromatography is the most useful method for organic chemicals because of the wide variety of separation and detection systems available. However, it must be recognized that it cannot solve the problem of resolving impurities that have chemical properties similar to those of the major component. A producer of pure chemicals must also recognize that proving the identity of a chemical is as important as proving the purity of the compound. It is sometimes impossible to publish chemical publications without information on compounds whose chemical structures have been misidentified; therefore, evidence of the identity of a substance is always an integral part of the traceability of a purity certificate.
A3.4 Trace elements in organic and inorganic substances (including water) The application of isotope desorption mass spectrometry (IDMS) overcomes many of the difficulties associated with the determination of trace elements. IDMS does not require quantitative separation of the sample to compare the ratio of the isotope atomic number of different substances to obtain the required results. In theory, it can be directly derived to the mole. Adding isotopes of the analyte elements to the sample and then homogenizing the isotopes, the mass spectrometry method can be used to determine the material ratio of the analyte and the tracer, and the "matrix effect" can be largely eliminated because the "matrix effect" has the same effect on the analyte and the tracer.
A3.5 Organic matrices and organic compounds in water. The most problematic standard samples for establishing traceability are trace pollutants in organic matrices (such as chlorinated biphenyls and hexachlorobenzene in animal fat), pollutants in water (such as pesticides in tap water), and clinical chemistry analysis (such as cholesterol in blood). Since IDMS requires that the tracer used should show extremely similar properties to the analyte during separation and extraction (of course, this is difficult to achieve), DMS cannot be completely satisfactory. A3.6 For other chemically stable compoundsor traceability to a national metrology laboratory. However, when determining the value of a standard sample of a chemical component, it is often more difficult to establish traceability. For example, although there is no difficulty in weighing a sample on a precision balance using a traceable and calibrated code, the analyte can rarely be determined by weighing. Often it is only after a quantitative process such as sampling, dissolution, extraction and chromatography, or more traditional wet chemical separation, that the actual measurement of the analytical instrument is concluded. Any or all of the above processes are links in the traceability chain and have their own uncertainties, so the chemist must assess the efficiency of each process in completely retaining the analyte (which may be retained unchanged or converted into another compound with which it has an ideal ratio) and in separating it from substances that interfere with the final measurement. When the characteristic value is expressed as an amount of substance, the chemist faces a special problem. Because balances are widely used in chemical experiments, the characteristic values ​​of most certified standard samples of chemical components are expressed in "mass ratio" or "mass concentration" rather than in moles to express "amount of substance". However, mass arithmetic is very similar to molar arithmetic, so the producer of standard samples only needs to prove that the method used is reliable for determining a specific analysis in a specific sample. For example, the units used are grams of lead per gram of blood or grams of animal tissue.
A2 Determination of the value of standard samples
The ISO Guide 35 used in this standard recognizes the following methods for determining the value of standard samples: a) measurement by a single, authoritative method in a single laboratory, measurement by one or more independent standard methods in a laboratory; b) measurement by a network of recognized laboratories using one or more confirmed methods. Authoritative methods are those whose characteristic values ​​can be directly measured in terms of basic units of measurement or can be directly related to natural units through physical or chemical theories expressed in accurate mathematical formulas. Therefore, the term also includes chemical analysis methods whose test results may not necessarily meet the requirements of VIM. Even if such high-quality analytical methods are available, they are required to be independently performed by two or more analysts, and preferably with unloaded experimental equipment. The premise of inter-laboratory testing is that there are some laboratories of the same level, the measurement methods used are considered to be independently recognized, and the differences between the results obtained are statistical in nature and can be treated with purely statistical procedures. Although this method is often used for value determination, it often only reflects the comparability between experiments and may lead to the recognition of incorrect values, especially when statistical treatment methods are considered to be more important than chemical knowledge and judgment. This problem is prone to occur. A sub-procedure of this procedure is to perform analysis using a specific method.
GB/T 15000.7 1997
Thus, the scope of traceability of reference materials can range from "a close comparative chain of traceability to SI base units through instrument calibration" to "application of a well-established standard method". In each of the above cases, the reference material producer needs to investigate how the relevant principles apply. In particu
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