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MVRRCNG0167 Verification Procedure for Atomic Absorption Spectrophotometer 1. Verification Procedure for Atomic Absorption Spectrophotometer Description Number
Responsible Organization
Drafting Organization
Main Drafter
Approval Date
Implementation Date
Alternative Procedure Number
Scope of Application
Main Technology
Whether Classified
Verification Period (Year)
Number of Appendixes
Publishing Organization
Verification Standard Materials
Related Technical Documents
JJG694-1990
(Chinese) Atomic Verification Regulation for Absorption Spectrophotometer (English)Verification
Regulation
Spectrophotometer
National Research Center for Standard Materials
National Research Center for Standard Materials
Zhang Dunhuang (National Research Center for Standard Materials)June 28, 1990
November 1, 1990
Atomic
Absorption
This regulation applies to the verification of single-beam and double-beam atomic absorption spectrophotometers (hereinafter referred to as instruments) that are newly manufactured, in use or after repair. 1
Appearance and preliminary inspection
Wavelength indication error and repeatability
Resolution
Baseline stability
Edge energy
Detection limit (G(=3)) and precision (RSD) of copper determined by flame method6
Detection limit (Q.ck=3)), characteristic quantity (CM) and precision of cadmium determined by graphite furnace method7
8Sample solution aspiration volume and apparent atomization rate
Background correction capability
10Insulation resistance
Newly manufactured instruments must be fully calibrated according to Articles 1 to 10: In principle, instruments in use and after repair shall be calibrated according to Articles 2 to 7 and Article 9, and Article 8 shall be added if necessary. No
China Metrology Press
2. Verification Procedure for Atomic Absorption Spectrophotometer Abstract 1 Overview
Atomic absorption spectrophotometer is an instrument that quantitatively analyzes the absorption degree of characteristic radiation by the ground state atoms of the measured element. Its measurement principle is based on the law of light absorption: Where A-
Absorbance (its unit is A):
Incident light intensity:
Transmitted light intensity:
Transmittance;
Absorption coefficient:
Concentration of measured element in sample:
-Light path length of light passing through the atomizer.
The main structural block diagram of the instrument is as follows:
Characteristic radiation
Light source
Atomizer
—1gT=KCL
Monochromator
Detection system
According to the beam form, the instrument can be divided into single-beam type and double-beam type: the atomizer can be divided into flame atomizer and flameless graphite furnace) atomizer, etc.
Technical requirements
1 Appearance and preliminary inspection
1.1 The instrument should have the following signs: instrument name, model, manufacturer name, factory number and factory date, etc. 1.2 All fasteners of the instrument and accessories should be well tightened: the connecting parts should be well connected: the moving parts should move flexibly and smoothly: the gas path system should be reliably sealed and leak-free. 1.3 The knobs and function keys of the instrument should be able to work normally: for instruments controlled by computers or with microcomputers, when commands are input from the keyboard, the corresponding functions should be normal. 2 Wavelength indication error and repeatability
Wavelength indication error is not greater than ±0.5nm, and wavelength repeatability is better than 0.3nm. 3 Resolution
When the instrument spectrum bandwidth is 0.2nm, it should be able to distinguish the manganese 279.5nm and 279.8nm double lines. 4 Baseline stability
The stability of the static baseline and ignition baseline within 30min should not be greater than the indicators listed in Table 1. Table 1
Static baseline
Ignition baseline
5 Edge energy
Maximum zero drift
Baseline stability
New manufacturing
Maximum instantaneous noise
Maximum zero drift
Maximum instantaneous noise
In use and after repair
At the edge wavelength of the instrument, it should be able to measure the arsenic 193.7nm and 852.1nm spectrum lines, and its instantaneous noise should be less than 0.03A.
6 The detection limit (G3) and precision (RSD) of copper determined by flame method shall not exceed 0.008μg/m1 and 1% for new instruments; the detection limit (Q(k=3)), characteristic quantity (CM) and precision (RSD) of copper determined by graphite furnace method shall not exceed 2pg, 1pg and 5% for new instruments; the detection limit (Q(k=3)), characteristic quantity (CM) and precision (RSD) of copper determined by graphite furnace method shall not exceed 4pg, 2pg and 7% for new instruments; the detection limit (Q(k=3)), characteristic quantity (CM) and precision (RSD) of copper determined by graphite furnace method shall not exceed 2pg, 1pg and 5% for new instruments; the detection limit (Q(k=3)), characteristic quantity (CM) and precision (RSD) of copper determined by graphite furnace method shall not exceed 4pg, 2pg and 7% for new instruments.
8 Sample solution aspiration volume and apparent atomization rate
The aspiration volume shall not be less than 3ml/min; the atomization rate shall not be less than 8%. 9 Background correction capabilitybZxz.net
When the background attenuation signal is about 1A, the corrected signal shall not exceed 30% of the value
10 Insulation resistance
The insulation resistance of the instrument shall not be less than 20M.
11 Newly manufactured instruments must be fully calibrated according to Articles 1 to 10; instruments in use and after repair shall in principle be calibrated according to Articles 2 to 7 and Article 9, and Article 8 shall be added if necessary. III. Calibration conditions
12 Environmental conditions
The instrument should be placed in a well-ventilated laboratory without severe vibration, corrosive gases, and no strong electromagnetic field interference nearby. There should be an exhaust system above the instrument. The room temperature should be 5 to 35°C, the relative humidity should not exceed 80%, the instrument power supply voltage is (220±22)V, and the frequency is (50±1)Hz.
13 Calibration equipment
13.1 Hollow cathode lamp: Hg, Cu, Mn, Cd, As, Cs, etc., its ignition performance and stability have been inspected and qualified. 13.2 Standard solution: This solution must be a standard substance approved and issued by the national metrology administration and provided by a unit with the corresponding standard substance "Manufacturing Measuring Instrument License". Its concentration and uncertainty are listed in Table 2. 13.3 Micropipette: 10, 20, 30u1. 13.4 Stopwatch: minimum scale 1s
13.5 Measuring cylinder: capacity 10ml, minimum scale 0.2ml. Table 2
Solution name
Sodium chloride
*For selection when necessary
13.6500V megohmmeter.
Concentration of standard solution and its uncertainty
0.5mol/1HNO3
μg/ml
13.7 Attenuator with light attenuation equivalent to 1A. 13.8 Deionized water: conductivity not greater than 0.1s/cm. Uncertainty
14 Appearance and preliminary inspection
IV. Verification items and verification methods
The appearance and preliminary inspection of the instrument shall comply with the provisions of Article 1. 15 Verification of wavelength indication error and repeatability
15.1 Measurement of wavelength
15.1.1 Light the mercury lamp according to the specified working current on the hollow cathode lamp. After it stabilizes, select three to five lines from the following mercury and chlorine spectral lines 253.7; 365.0; 435.8: 546.1; 640.2; 724.5 and 871.6nm according to the principle of uniform distribution, and make three unidirectional (from short wave to long wave) measurements one by one, giving the wavelength indication with the maximum energy as the measured value, and then calculate the wavelength indication error and repeatability according to the method of Section 15.2. 15.1.2 For instruments that automatically set the wavelength, the measured wavelength value can be read from the printed spectral line profile or the display screen.
15.2 Calculation of wavelength indication error and repeatability 15.2.1 Wavelength indication error (△^) is calculated as follows: 3
Where ^ is the standard value of the wavelength of the mercury and thiophene lines; ^ is the measured value of the wavelength of the mercury and thiophene lines,
15.2.2 Wavelength repeatability (8) is calculated as follows: Where ^max is the maximum value of the three wavelength measurements of a certain spectral line; Amin is the minimum value of the three wavelength measurements of a certain spectral line. 16 Resolution verification
8=AmaxAmin
Light up the manganese lamp and wait for it to stabilize. The spectrum bandwidth is 0.2nm. Adjust the high voltage of the photomultiplier tube so that the energy of the 279.5nm spectrum line is 100. Then scan and measure the manganese double line. At this time, the 279.5 and 279.8nm spectrum lines should be clearly distinguishable, and the peak-to-valley energy between the two lines should not exceed 40%.
17: Baseline stability verification
17.1 Static baseline stability, spectrum bandwidth 0.2nm, the range is expanded by 10 times, the copper lamp is lit, and the measurement is carried out according to the following steps when the atomizer is not working: 17.1.1 Preheat the single-beam instrument and the copper lamp at the same time for 3 minutes, use the "instantaneous" measurement method, or the time constant is not greater than 0.5S, and measure the stability of the 324.7nm spectrum line, that is, the maximum drift and instantaneous noise (peak-to-peak value) within 30 minutes. 17.1.2 Preheat the double-beam instrument for 30 minutes, preheat the copper lamp for 3 minutes, and then measure the maximum drift and instantaneous noise (peak-to-peak value) within 30 minutes according to 17.1.1.
17.2 Ignition baseline stability, according to the optimal conditions for measuring copper, ignite the acetylene/air flame, and absorb and spray deionized water. After 10 minutes, repeat the measurement of 17.1 under the condition of absorbing and spraying deionized water. The maximum drift and instantaneous noise within 30 minutes should meet the requirements of Article 4.
18 Edge Energy Verification
Light up the arsenic and chromium lamps, wait for them to stabilize, and then measure the As193.7nm and Cs852.1nm spectral lines in accordance with 18.1 and 18.2 (or 18.3) under the conditions of a spectral bandwidth of 0.2nm and a response time of no more than 1.5s (the instrument can be used under the conditions recommended by the manufacturer after use and repair). 18.1 The peak energy of the two spectral lines should be adjustable to 100%, and the background value/peak value should be no more than 2%. 18.2 Measure the instantaneous noise of the spectral lines, and the maximum instantaneous noise (peak-to-peak value) within 5 minutes should be no more than 0.03A. 18.3 When the two spectral lines are adjusted to 100% energy, the high voltage of the photomultiplier tube shall not exceed 650V, and the instrument can be relaxed to 85% of the maximum high voltage value after use and repair. 19.1 Adjust the instrument parameters to the best working state, adjust to zero with blank solution, and perform three repeated measurements on the three copper standard solutions. After taking the average of the three measurements, calculate the slope of the working curve by linear regression, which is the sensitivity (S) of the instrument for copper measurement.
S=dA/dC(A/(μg·ml-1))
19.2 Under the same conditions as 19.1, expand the scale by 10 times, measure the absorbance of the blank solution (or solution with a concentration three times the detection limit) 11 times, and calculate its standard deviation (sA). 19.3 Calculate the detection limit of copper by the instrument as follows: CL (K = 3) = 3sA/S (μg/ml)
20 Precision verification of copper measurement by flame atomization method (5)
When carrying out the determination in Article 19, select a solution from the series of standard solutions so that the absorbance is in the range of 0.1 to 0.3. Perform seven measurements and calculate the relative standard deviation (RSD), which is the precision of the instrument for copper measurement. 21.1 Adjust the instrument parameters to the best working state, and repeat the measurement of the blank and three cadmium standard solutions three times. After taking the average value of the three measurements, calculate the slope of the working curve by linear regression, which is the sensitivity (S) of the instrument measurement. S=dA/dg=dA/d(CXV)
Wherein, C solution concentration (ng/ml):
V sampling volume (ul).
(A/pg)
21.2 Under the same conditions as in 21.1, measure the absorbance of the blank solution 11 times and calculate its standard deviation (SA).
21.3 Calculate the detection limit of cadmium by the instrument according to the following formula: QL(K =3)=3sA/S(g)
21.4 The characteristic quantity (CM) of cadmium determined by the instrument is calculated as follows: c.0044
22 Verification of the precision of the graphite furnace atomization method (7)
When carrying out the determination in Article 21, the 3.00ng/ml cadmium standard solution is measured seven times, and its relative standard deviation (RSD) is calculated, which is the precision of the instrument. 23 Verification of the aspiration volume (F) and apparent atomization rate (e) of the sample solution 23.1 Under the same conditions as Article 19, inject deionized water into a 10ml measuring cylinder to the top mark, insert a capillary into the bottom of the measuring cylinder, and start a stopwatch at the same time to measure the volume of water reduced in the measuring cylinder within 1 minute, which is the aspiration volume (F). 23.2 Remove the injection capillary from the water surface, and after no more waste liquid is discharged from the outlet of the waste liquid pipe, connect it to a 10ml measuring cylinder (measuring cylinder 1) (note: maintain a water seal). Inject 10ml of water into another measuring cylinder (measuring cylinder 2), and under the same conditions as in 23.1, insert the capillary into the water until all 10ml of water is absorbed and sprayed. After no more waste liquid is discharged from the waste liquid pipe, measure the volume V (ml) of the discharged waste liquid, and calculate the apparent atomization rate (e): 1
24 Background correction capability verification
24.1 For instruments with only a flame atomizer, first measure with the no-background correction method at a wavelength of Cd228.8nm! After zeroing, insert the screen (absorbance is about 1) into the light path, read the absorbance A, and then change the measurement method to background correction. mode, after zeroing, insert the screen into the optical path and read the absorbance A. 24.2 For instruments with graphite furnaces, adjust the instrument parameters to the best state for measuring cadmium by the graphite furnace method, first perform background-free correction measurement by peak height measurement, add a certain amount of sodium chloride solution (the concentration of the solution is 5.0 mg/ml, which can be diluted if necessary) with a pipette to generate an absorption signal of about 1A, read the absorbance Ai, and then measure with background correction, add the same amount of sodium chloride solution and read the absorbance A2. 24.3 After measuring A and A according to the method of 24.1 or 24.2, the calculated A/A value shall comply with the provisions of Article 9. 25 Insulation resistance verification
Use a 500V megohmmeter to measure the resistance between the power cord and the instrument housing, which shall comply with the provisions of Article 10. V. Verification result processing and verification cycle
26 For instruments that pass the verification, a verification certificate shall be issued: for instruments that fail the verification, a verification result notice shall be issued. 27 For instruments in use or after repair, baseline stability, precision and detection limit (graphite furnace also includes characteristic quantities) are the main items listed in the calibration items. If one of these items is unqualified, the metrological performance of the entire machine is unqualified; if these items are qualified, and other individual items are unqualified, but it does not affect the use, a calibration certificate can be issued, but the name of the unqualified item must be indicated in the "Conclusion" column on the back of the certificate, or it must be noted under what circumstances the instrument is allowed to be used. 28 The calibration cycle is two years. Repaired instruments should be calibrated at any time. Note: If you need to read the full text, please contact the publishing unit.3 Calculate the detection limit of copper by the instrument as follows: CL (K = 3) = 3sA/S (μg/ml)
20 Precision verification of copper measurement by flame atomization method (5)
When carrying out the measurement in item 19, select a solution from the series of standard solutions so that the absorbance is in the range of 0.1 to 0.3. Perform seven measurements and calculate the relative standard deviation (RSD), which is the precision of the instrument for copper measurement. 21.1 Adjust the instrument parameters to the best working state, and repeat the measurement of the blank and three cadmium standard solutions three times. After taking the average value of the three measurements, calculate the slope of the working curve by linear regression, which is the sensitivity (S) of the instrument measurement. S=dA/dg=dA/d(CXV)
Wherein, C solution concentration (ng/ml):
V sampling volume (ul).
(A/pg)
21.2 Under the same conditions as in 21.1, measure the absorbance of the blank solution 11 times and calculate its standard deviation (SA).
21.3 Calculate the detection limit of cadmium by the instrument according to the following formula: QL(K =3)=3sA/S(g)
21.4 The characteristic quantity (CM) of cadmium determined by the instrument is calculated as follows: c.0044
22 Verification of the precision of the graphite furnace atomization method (7)
When carrying out the determination in Article 21, the 3.00ng/ml cadmium standard solution is measured seven times, and its relative standard deviation (RSD) is calculated, which is the precision of the instrument. 23 Verification of the aspiration volume (F) and apparent atomization rate (e) of the sample solution 23.1 Under the same conditions as Article 19, inject deionized water into a 10ml measuring cylinder to the top mark, insert a capillary into the bottom of the measuring cylinder, and start a stopwatch at the same time to measure the volume of water reduced in the measuring cylinder within 1 minute, which is the aspiration volume (F). 23.2 Remove the injection capillary from the water surface, and after no more waste liquid is discharged from the outlet of the waste liquid pipe, connect it to a 10ml measuring cylinder (measuring cylinder 1) (note: maintain a water seal). Inject 10ml of water into another measuring cylinder (measuring cylinder 2), and under the same conditions as in 23.1, insert the capillary into the water until all 10ml of water is absorbed and sprayed. After no more waste liquid is discharged from the waste liquid pipe, measure the volume V (ml) of the discharged waste liquid, and calculate the apparent atomization rate (e): 1
24 Background correction capability verification
24.1 For instruments with only a flame atomizer, first measure with the no-background correction method at a wavelength of Cd228.8nm! After zeroing, insert the screen (absorbance is about 1) into the light path, read the absorbance A, and then change the measurement method to background correction. mode, after zeroing, insert the screen into the optical path and read the absorbance A. 24.2 For instruments with graphite furnaces, adjust the instrument parameters to the best state for measuring cadmium by the graphite furnace method, first perform background-free correction measurement by peak height measurement, add a certain amount of sodium chloride solution (the concentration of the solution is 5.0 mg/ml, which can be diluted if necessary) with a pipette to generate an absorption signal of about 1A, read the absorbance Ai, and then measure with background correction, add the same amount of sodium chloride solution and read the absorbance A2. 24.3 After measuring A and A according to the method of 24.1 or 24.2, the calculated A/A value shall comply with the provisions of Article 9. 25 Insulation resistance verification
Use a 500V megohmmeter to measure the resistance between the power cord and the instrument housing, which shall comply with the provisions of Article 10. V. Verification result processing and verification cycle
26 For instruments that pass the verification, a verification certificate shall be issued: for instruments that fail the verification, a verification result notice shall be issued. 27 For instruments in use or after repair, baseline stability, precision and detection limit (graphite furnace also includes characteristic quantities) are the main items listed in the calibration items. If one of these items is unqualified, the metrological performance of the entire machine is unqualified; if these items are qualified, and other individual items are unqualified, but it does not affect the use, a calibration certificate can be issued, but the name of the unqualified item must be indicated in the "Conclusion" column on the back of the certificate, or it must be noted under what circumstances the instrument is allowed to be used. 28 The calibration cycle is two years. Repaired instruments should be calibrated at any time. Note: If you need to read the full text, please contact the publishing unit.3 Calculate the detection limit of copper by the instrument as follows: CL (K = 3) = 3sA/S (μg/ml)
20 Precision verification of copper measurement by flame atomization method (5)
When carrying out the measurement in item 19, select a solution from the series of standard solutions so that the absorbance is in the range of 0.1 to 0.3. Perform seven measurements and calculate the relative standard deviation (RSD), which is the precision of the instrument for copper measurement. 21.1 Adjust the instrument parameters to the best working state, and repeat the measurement of the blank and three cadmium standard solutions three times. After taking the average value of the three measurements, calculate the slope of the working curve by linear regression, which is the sensitivity (S) of the instrument measurement. S=dA/dg=dA/d(CXV)
Wherein, C solution concentration (ng/ml):
V sampling volume (ul).
(A/pg)
21.2 Under the same conditions as in 21.1, measure the absorbance of the blank solution 11 times and calculate its standard deviation (SA).
21.3 Calculate the detection limit of cadmium by the instrument according to the following formula: QL(K =3)=3sA/S(g)
21.4 The characteristic quantity (CM) of cadmium determined by the instrument is calculated as follows: c.0044
22 Verification of the precision of the graphite furnace atomization method (7)
When carrying out the determination in Article 21, the 3.00ng/ml cadmium standard solution is measured seven times, and its relative standard deviation (RSD) is calculated, which is the precision of the instrument. 23 Verification of the aspiration volume (F) and apparent atomization rate (e) of the sample solution 23.1 Under the same conditions as Article 19, inject deionized water into a 10ml measuring cylinder to the top mark, insert a capillary into the bottom of the measuring cylinder, and start a stopwatch at the same time to measure the volume of water reduced in the measuring cylinder within 1 minute, which is the aspiration volume (F). 23.2 Remove the injection capillary from the water surface, and after no more waste liquid is discharged from the outlet of the waste liquid pipe, connect it to a 10ml measuring cylinder (measuring cylinder 1) (note: maintain a water seal). Inject 10ml of water into another measuring cylinder (measuring cylinder 2), and under the same conditions as in 23.1, insert the capillary into the water until all 10ml of water is absorbed and sprayed. After no more waste liquid is discharged from the waste liquid pipe, measure the volume V (ml) of the discharged waste liquid, and calculate the apparent atomization rate (e): 1
24 Background correction capability verification
24.1 For instruments with only a flame atomizer, first measure with the no-background correction method at a wavelength of Cd228.8nm! After zeroing, insert the screen (absorbance is about 1) into the light path, read the absorbance A, and then change the measurement method to background correction. mode, after zeroing, insert the screen into the optical path and read the absorbance A. 24.2 For instruments with graphite furnaces, adjust the instrument parameters to the best state for measuring cadmium by the graphite furnace method, first perform background-free correction measurement by peak height measurement, add a certain amount of sodium chloride solution (the concentration of the solution is 5.0 mg/ml, which can be diluted if necessary) with a pipette to generate an absorption signal of about 1A, read the absorbance Ai, and then measure with background correction, add the same amount of sodium chloride solution and read the absorbance A2. 24.3 After measuring A and A according to the method of 24.1 or 24.2, the calculated A/A value shall comply with the provisions of Article 9. 25 Insulation resistance verification
Use a 500V megohmmeter to measure the resistance between the power cord and the instrument housing, which shall comply with the provisions of Article 10. V. Verification result processing and verification cycle
26 For instruments that pass the verification, a verification certificate shall be issued: for instruments that fail the verification, a verification result notice shall be issued. 27 For instruments in use or after repair, baseline stability, precision and detection limit (graphite furnace also includes characteristic quantities) are the main items listed in the calibration items. If one of these items is unqualified, the metrological performance of the entire machine is unqualified; if these items are qualified, and other individual items are unqualified, but it does not affect the use, a calibration certificate can be issued, but the name of the unqualified item must be indicated in the "Conclusion" column on the back of the certificate, or it must be noted under what circumstances the instrument is allowed to be used. 28 The calibration cycle is two years. Repaired instruments should be calibrated at any time. Note: If you need to read the full text, please contact the publishing unit.
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