Some standard content:
GB18350--2001
This standard is a mandatory national standard in its entirety. Fore
This standard is equivalent to the American Society for Testing and Materials standard ASTMD4806-99 "Specifications for Denatured Ethanol Mixed with Gasoline for Use as Fuel for Ignition-Type Vehicle Engines" in terms of technical content. The main differences between this standard and ASTMD4806--99 are: 1. The water content is stipulated to be no more than 0.8% (V/V). This is stricter than the maximum water content of 1% (V/V) stipulated in ASTMD4806-99:
2. Denaturants are only allowed to be added to unleaded gasoline for vehicles that meets the requirements of GB17930-1999: 3. The measurement unit of the copper content limit indicator has been modified from no more than 0.1 mg/kg to no more than 0.08 mg/1. Denatured fuel ethanol is not drinkable, so it is different from GB10343-1989 Edible Alcohol: It is also different from the general GB/T394.1-1994 (industrial alcohol). Appendices A, B, C, D, E and F of this standard are all standard appendices. This standard is proposed by the State Administration of Quality and Technical Supervision. This standard is technically managed by the China Food Fermentation Industry Research Institute. Drafting units of this standard: China Food Fermentation Industry Research Institute, Petrochemical Research Institute of China Petrochemical Corporation, Henan Tianguan Enterprise Group Co., Ltd. Co., Ltd., Heilongjiang Huarun Jinyu Industrial Co., Ltd., Jilin Tianhe Alcohol Co., Ltd., Anhui Fengyuan Biochemical Co., Ltd.
The main drafters of this standard are Tian Qijing, Guo Xinguang, Yang Guoxun, Yang Tingting, Kong Xianzhang, Wang Zhiqiang, Yue Guojun, Gu Naida, Wang Wei, Chen Xihai, Cheng Maoji, Chang Zhukuai.
This standard is interpreted by the Chinese Institute of Food Fermentation Industries. 88
1 Scope
National Standard of the People's Republic of China
Denatured Fuel Ethanol
Denatured fuel ethanol
GB18350--2001
This standard specifies the definition, requirements, test methods, inspection rules and marking, packaging, transportation and storage requirements of denatured fuel ethanol. This standard applies to fuel ethanol denatured by adding denaturant (unleaded gasoline for vehicles) after dehydration using starch and sugar as raw materials to produce ethanol through fermentation and distillation. It can be mixed with gasoline in a specified proportion as fuel for spark-ignition internal combustion engines for vehicles. Cited standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and the parties using this standard should explore the possibility of using the latest versions of the following standards. GB190—1990 Dangerous Goods Packaging Marking
GB3191—2000 Pictorial Marking for Packaging Storage and TransportationGB/T394.2—1994 General Test Method for AlcoholGB/T 601 -1988
GB/T 602-1988
GB/T 603—1988
GB/T 611-1988
GB/T 683-1979
GB/T 6682—1992
GB/T 8019—1987
GB/T 9722--1988
GB/T 9724--1988
GB/T 9725--1988
GB 179301999
GB J16..-1987
GB J72--1984
Chemical reagents-Preparation of standard solutions for titration analysis (volumetric analysis)Chemical reagents
Preparation of standard solutions for impurity determination
Chemical reagents
Preparation of preparations and products used in experimental methodsChemical reagents
Chemical reagents
General method for density determination
Specifications and test methods for water in analytical laboratoriesDetermination of actual colloid content of gasoline and aviation fuel (jet evaporation method)General rules for gas chromatography
Chemical reagents
Chemical reagents
General rules for pH determination
Chemical reagents
General rules for potentiometric titration
Unleaded gasoline for vehicles
Code for fire protection design of buildings
Code for design of petroleum depots
SH/T06042000Determination of density of crude oil and petroleum products (U-shaped vibrating tube method) 3 Definitions
This standard adopts the following definitions.
3.1 Fuel ethanol fuel ethanol
Anhydrous ethanol that can be used as fuel without denaturant. 3.2 Denaturant
Unleaded gasoline added to fuel ethanol to make it undrinkable but suitable for use as fuel for spark-ignition internal combustion engines for vehicles, approved by the State Administration of Quality and Technical Supervision on April 2, 2001 and implemented on April 15, 2001
GB 18350--2001
3.3 Denatured fuel ethanol denatured fuel ethanol fuel ethanol that is not suitable for drinking after adding denaturant. 3.4 pHe value
Measurement of the acid strength in denatured fuel ethanol. 4 Requirements
4.1 Requirements for main raw materials
4.1.1 Fuel ethanol
The density of fuel ethanol at 20°C should be within the range of 0.7918g/cm2~0.7893g/cm2. 4.1.2 Denaturant
The denaturant added to fuel ethanol shall comply with the requirements of GB17930-1999 "Unleaded Gasoline for Motor Vehicles", but oxygen-containing compounds shall not be added. 4.2 Technical Requirements
4.2.1 Denaturant Addition Amount
The volume mixing ratio of fuel ethanol and denaturant shall be 100:2~100:5, that is, the volume percentage of denaturant in denatured fuel ethanol shall be 1.96% (V/V)~4.76% (V/V). 4.2.2 Physical and Chemical Requirements
Denatured fuel ethanol shall comply with the requirements of Table 1.
Ethanol %(V/V)
Methanol.%(V/V)
Actual colloid, mg/100ml.
Water, %(V/V)
Inorganic chlorine (as Cl\).mg/L
Acidity (as acetic acid)), mg/L
pHe value:
1) Before April 1, 2002, pHe value shall be temporarily implemented as 5.7～9.0. Means
Clear and transparent, without visible suspended matter and sediment 92.1
Note: Effective metal corrosion inhibitors should be added to meet the corrosion requirements of automotive ethanol gasoline sheets. 5 Test methods
5.1 Main raw materials
5.1.1 Density of fuel ethanol
Determine its density according to the density bottle method in 5.1 of GB/T611-~1988 or the digital density meter method in SH/T0604. At 20°C, the density should be in the range of 0.7918g/cm3~0.789 3g/cm2. 5.2 Denatured fuel ethanol
5.2.1 Appearance
At room (normal temperature) ambient temperature, take 50ml of the sample and put it in a 100mL colorimetric tube. Visually observe under bright light. The sample should be clear and transparent, without impurities such as suspended matter and sediment visible to the naked eye. 5.2.2 Ethanol
Determine according to the method in Appendix A.
5.2.3 Methanol
Determine according to the method in Appendix A.
5.2.4 Actual colloid
Measured according to the method of GB/T8019,
5.2.5 Water
Measured according to the method of Appendix B.
5.2.6 Inorganic chlorine
Measured according to the method of Appendix C.
5.2.7 Acidity
Measured according to the method of Appendix I.
Measured according to the method of Appendix E.
5.2.9 pHe value
Measured according to the method of Appendix F,
6 Inspection rules
6.1 Batch
GB 18350—2001
Products are accepted in batches. For products packaged in cans or tank trucks, each can or tank truck is considered a batch. If this definition is not used, the definition of batch shall be determined by negotiation between the buyer and the seller. 6.2 Sampling
6.2.1 Sampling method
6.2.1.1 Use the stainless steel sampler to be manufactured (see Figure 1 for a schematic diagram). 6.2.1.2 For products loaded in tank trucks, take samples from the middle part at one time. For canned products, samples should be taken from the upper, middle and lower parts of the liquid in the container. The vertical tank should be sampled in a volume ratio of 2:3:2, and the horizontal tank should be sampled in a volume ratio of 1:3:1, and then mixed and put into a glass bottle. wwoo
When injecting
Figure 1 Sampler
When sinking
6.2.2 Sampling volume
GB 18350--2001
Take 2I samples from each batch, mix them evenly, and pack them into two 1L narrow-mouthed glass reagent bottles. Affix labels and indicate: product name, batch number (tank, tank truck number), manufacturer name, sampling date, location, and sampler. One bottle is sent to the laboratory for testing, and the other bottle is sealed and kept for one month for inspection. 6.3 Inspection classification
6.3.1 Factory inspection
6.3.1.1 Before the product leaves the factory, the quality supervision and inspection department of the manufacturer shall conduct inspections in accordance with the provisions of this standard. Only those that pass the inspection and issue a quality inspection report can be sold. 6.3.1.2 Factory inspection items: appearance, ethanol, methanol, moisture, inorganic fluorine, acidity and pHe value. 6.3.2 Type inspection
6.3.2.1 Type inspection items: all physical and chemical requirements of 4.2.2. 6.3.2.2 Type inspection is conducted every six months and should also be conducted in any of the following situations: a) When replacing equipment or main raw materials; b) When resuming production after a long-term shutdown; c) When the inspection results are significantly different from those of the previous type inspection; d) When the national quality supervision and inspection agency conducts random inspections. 6.4 Judgment rules 6.4.1 If one of the factory inspection results does not meet the requirements of this standard, two times the amount of samples should be re-sampled from the original sampling batch for re-inspection, and the re-inspection results shall prevail. If there is still one indicator that fails to meet the requirements, the batch of products shall be judged as unqualified. 6.4.2 The judgment rules for type inspection are the same as those for factory inspection. 7 Marking, packaging, transportation, purchase and storage 7.1 Marking 7.1.1 The tank truck or tanker for shipping should be marked with: product name "denatured fuel ethanol", manufacturer's name and address, and a clear "not drinkable" warning sign.
7.1.2 The packaging, storage and transportation diagrams and signs shall comply with the requirements of GB190 and GB191. 7.2 Packaging
7.2.1 Special tank trucks or tank trucks shall be used for transportation. Before packaging, the containers used shall be strictly checked for safety, cleanliness, anhydrousness and sealing. 7.2.2 The tank trucks or tank trucks shall be sealed after filling. After receiving the goods, the user unit shall first check whether the seal is intact, and then check the quantity and quality of the products.
7.3 Transportation
7.3.1 The means of transportation (including tank trucks or tank trucks, etc.) shall be clean and anhydrous. It shall not be mixed with flammable, explosive and corrosive items. During transportation, the inhalation of external water shall be prevented. 7.3.2
7.3.3 The exhaust pipe of the transportation vehicle must be equipped with a flame arrester, and fire extinguishing equipment and anti-static facilities shall also be provided. 7.3.4 Loading and unloading should be done with care to prevent violent shock and impact; and should be kept away from heat sources and fire sources. 7.4 Compensation for storage
7.4.1 The storage area should comply with the requirements of GBJ16 building fire protection design specifications. At the same time, a fire protection system should be established in accordance with GBJ72 oil depot design specifications. 7.4.2 Finished product storage tanks must be equipped with breathing valves with desiccant, and storage tanks must have protection measures against lightning and static electricity; open-air tanks should have spray water or other cooling facilities.
7.4.3 Products must not be stored together with flammable, explosive, or corrosive items. It should also be separated from the storage area of "edible alcohol". 7.4.4 There should be a conspicuous "No Fire" warning sign in the storage area. 92
A1 Scope
GB18350-2001
(Appendix to the standard)
Determination of ethanol and methanol content in denatured fuel ethanol (gas chromatography) A1.1 This method is applicable to the determination of ethanol and methanol content in denatured fuel ethanol by gas chromatography. A1.2 The determination range of this method: ethanol from 93% (m/m) to 97% (m/m), methanol from 0.1% (m/m) to 0.6% (m/m). This method also provides the formula for converting the mass percentage of these two alcohols (m/m) to volume percentage (V/V), A 1.3 This method can be used for qualitative and quantitative determination of ethanol and methanol, but cannot be used for qualitative determination of all components in denatured fuel ethanol.
A1.4 This method cannot be used to determine the water content in denatured fuel ethanol. The water content should be determined according to Appendix B and the alcohol content result measured by gas chromatography should be corrected.
A1.5 This method is not suitable for the determination of components with a boiling point higher than 225C in denatured fuel ethanol, or components with weak or no detection signal by flame ionization detector (such as water). A2
Method Summary
The sample enters a chromatograph equipped with a quartz capillary column bonded with methyl silicone. With the transmission of nitrogen as the carrier gas, the vaporized sample passes through the chromatographic column. During the chromatographic distribution process, Each component is separated, and the components flowing out of the chromatographic column are detected by a flame ionization detector, and the signal obtained by the detector is processed by an electronic data receiving system. Under exactly the same conditions, the retention time of ethanol and methanol is compared with that of the analytical standard sample for qualitative analysis, and the peak area normalization method is used for quantitative analysis to determine the mass percentage of each component, and then converted into volume percentage.
: A3 Instruments and equipment
A3.1 Gas chromatograph
A3.1.1 It should be able to operate under the chromatographic conditions listed in Table A1: A3.1.2 It should have a hot flash injector that can achieve linear splitting of the sample (such as 200:1); A3.1.3 It should be able to control the carrier gas very accurately so that the column flow rate and split ratio have good reproducibility;: A3.1.4 It should be able to withstand high pressure, automatically adjust pressure and stabilize flow, and the pressure control and metering devices should be able to reach the linear speed used by the capillary column; A3.1.5 The flame ionization detector (FID) connected to the gas control and electronic equipment should have the best response value for the open column: 43.1.6 The electronic data receiving and processing system used should meet or exceed the following minimum requirements: that is, it can accommodate at least 100 peaks for analysis: it can calculate the normalized peak area percentage using the correction factor; it can qualitatively identify the components according to the retention time of each component; it can eliminate noise; it has sufficient sampling rate for very fast peaks (<1s); it can correct the positive and negative tilted baselines; it can compensate for the sensitivity of narrow and broad peaks; for difficult-to-separate peaks, it can perform vertical or tangential cutting as needed. 43.2 Chromatographic column
A3.2.1 A non-polar bonded (cross-linked) open capillary column coated with methyl silicone is used, with a column length of 150m, an inner diameter of 0.25mm, and a coating thickness of Jum.
A3.2.2 Or choose a chromatographic column with better chromatographic separation efficiency and selectivity. A3.3 Micro syringe: 0.5uL, 1μl. A4. Chromatographic conditions
According to different instruments, select the best chromatographic operating conditions through experiments to ensure that methanol and ethanol can be completely separated from the other component peaks. 93
is the standard: The recommended typical chromatographic operating conditions are shown in Table A1. GB18350—2001wwW.bzxz.Net
Recommended typical chromatographic operating conditions
Column temperature control
Starting temperature
Initial column temperature holding time
Program temperature rise rate
End temperature
End temperature holding time
Split ratio
Injection volume
Gas (hydrogen)
Auxiliary gas (air)
Supplementary gas (nitrogen)
Average linear velocity
A5 Reagents and materials
20 min
First stage rise 15C/min to 120 C
Second stage rise 30C/min to 250℃
250℃
25 min
Injector
Range 30℃/min to 250℃
0. 1 μL~0. 5 μL
Detector
Flame ionization detector
300℃
30mL/min
300 mL/min
30 mL/min
20 cm/s~24 cm/s
The reagents used in this test method are analytically pure unless otherwise specified. A5.1 Standard samples used for calibration and qualitative analysis All components to be measured should be qualitatively determined using the retention time of the standard sample and quantitatively calibrated using the standard sample. The purity of the standard sample should be known and should not contain other components to be analyzed. A5.1.1 Ethanol: purity of at least 99.5%. A5.7.2 Methanol: purity of at least 99.5%. A5.1.3 n-heptane: purity of at least 99.5%, A5.2 Carrier gas: nitrogen purity shall not be less than 99.99%. Oxygen removal system and gas purification device shall be used. A5.3 Detector gas: hydrogen, air and nitrogen. The purity of oxygen and nitrogen used shall not be less than 99.99%, and air shall not contain hydrocarbons. It is recommended that gas purification device should also be used for detector gas. A6 Instrument preparation
A6.1. Column loading and aging should be carried out according to the method instructed by the manufacturer or supplier. After column aging, connect the outlet of the column to the manhole of the flame ionization detector, and check the air tightness of the entire system. If leakage is found, it should be handled in time before measurement. GB18350--2001
A6.2 Operate at the initial temperature and adjust the carrier gas flow rate so that its average linear velocity reaches 20cm/s~24cm/s. When using methane for measurement, the average linear velocity can be calculated according to formula (A1): (A1)
Where: u—average linear velocity.cm/s;
L. Column length, cm
tm-retention time of methane, s.
A6.3 Adjust the gas chromatography operating conditions to the state of Table A1, and make the entire system completely balanced. A6.4 Linearity
Before measuring the sample, the linear state of the gas chromatography system should be established. A6.4.1 The split ratio depends on the split performance of the injector and the column capacity of the sample. For a specific column, the capacity of the sample component is proportional to the amount of solid and liquid phase (loading and liquid film thickness), and is proportional to the ratio of column temperature to component boiling point (vapor pressure). Since the retention time of the overloaded peak may shift, column overloading may lead to a decrease in the separation of some component peaks, which may cause errors in the quantification of component peaks. When estimating the column capacity and determining the split ratio, it should be noted that if a front deflection (tongue extension) peak appears, it indicates that the column capacity is overloaded. In the actual analysis process, attention should be paid to the volume of the injected component to avoid overloading. A6.4.2 The split ratio determines the measurement parameters and measurement range for correct quantification. This method uses a mixture of ethanol, methanol and 10 to 20 pure hydrocarbons with known mass percentages and suitable for the boiling point range of this method. The mass percentage of these components is determined, and the relative error with the known mass concentration shall not exceed ± 3%. A6.4.3 Pay attention to check the linearity of the flame ionization detector. The relationship between the peak area and the concentration of the prepared standard ethanol should be linear within the measurement range. If it is not linear, the split ratio should be increased or the sensitivity of the detector should be reduced. A7 Qualitative and quantitative
A7.1 Qualitative
Use n-heptane as the solvent to prepare ethanol and methanol standards, inject them separately, and measure their retention times, or use a standard sample with a known mixture in proportion to measure the retention times of ethanol and methanol. A7.2 Calibration
Typical relative mass calibration factors for ethanol and methanol are shown in Table A2. These calibration factors should be obtained by measuring the mixed standard sample according to the GB/T9722 method. The ratio of ethanol and methanol in this standard sample should be basically the same as that of the sample to be tested, except that n-heptane is used instead of the denaturant. The typical composition of the mixed standard sample is approximately: 96% ethanol, 0.1% methanol and 3.9% n-heptane. Table A2 Related physical constants
1) When n-heptane-1.
A8 Operation steps
Typical relative mass correction factor 1
A8.1 Adjust the parameters of the gas chromatograph to the conditions listed in Table A1. A8.2 Adjust the sensitivity of the instrument so that it can detect components to 0.002% (m/m). Density at 20°C
A8.3 Use a manual or automatic liquid syringe to inject 0.1μI.~0.5μL into the injection port of the instrument, and analyze to obtain the chromatogram (see Figure A1) and the data of each component peak.
Note: The appropriate micro-syringe and injection volume should be selected. It is particularly important to note that inappropriate split ratio, incorrect injection operation and injection volume exceeding the capillary column load will lead to inaccurate analysis results. Overloading should be avoided during the analysis, especially overloading of ethanol. 95
(Norm)
GB 18350—2001
Figure A1 Typical sample chromatogram
Time surface (min)
A8.4 If the retention time of methanol and the first component peak in the denaturant are too close (or the separation is not good), it is necessary to select the separation conditions first, increase the retention time of the two (or completely separate them), so that the instrument can easily identify them, and then perform qualitative and quantitative analysis, otherwise it will be misjudged. If the denaturant component appears at the tail of the ethanol peak, tangent cutting should be used for integral correction. A8.5 Determine the moisture content % (m/m) according to the method in Appendix B of this standard. Then correct the ethanol and methanol contents. A8.6 Measure the density of the denatured fuel ethanol sample according to GB/T611 or SH/T0604 so that after deducting the moisture, it can be converted into the actual volume percentage of ethanol and methanol in the sample. A9 Calculation
A9.1 Multiply the peak areas of qualitative ethanol and methanol by the corresponding relative mass correction factors. These correction factors are actually measured with the corresponding standard samples. The relative mass correction factor for unknown components can be taken as 1.00. The mass percentage of each component before moisture correction is calculated according to formula (A2): RM.
AR,X100
-Relative mass percentage of a certain alcohol component (before moisture correction), % (m/m); where: RM.-
AR,--peak area of a certain alcohol component after correction with the corresponding mass correction factor; AR,--total area of all detected peaks after correction with their corresponding mass correction factors. A9.2 The mass percentage of a certain alcohol component after moisture correction is calculated according to formula (A3): RM X (100 - X)
Wherein: M1 - the mass percentage of a certain alcohol component after moisture correction, % (m/m); RM2 - the mass percentage of the alcohol component calculated by formula A2), % (m/m); X - the moisture content, % (m/m).
A9.3 The mass percentage of a certain alcohol component is converted into volume percentage, calculated according to formula (A4): M, X Ps
Where: V,--volume percentage of a certain alcohol component, %(V/V); M--mass percentage of the alcohol component calculated by formula (A3), %(m/m); 96
(A3)
GB 18350--2001
ps--density of the alcohol component at 20C, g/cm; P.--density of the denatured fuel ethanol sample measured, g/cm\. A10 Precision (95% confidence level)
Repeatability: The difference between two results obtained by repeated determination of the same sample in the same laboratory, by the same analyst using the same instrument, under the same operating parameters, with standard and accurate operations, should not exceed the following value (see Table A3). Table A3 Repeatability
93·97
0. 01～0. 6
Note: X is the average of two results obtained from repeated measurements Repeatability
0. 018 59 × x
%(m/m)
A10.2 Reproducibility: When the same measurement is performed by different analysts in different laboratories, the difference between two independent measurement results should not exceed the following value (see Table A4).
Table A4 Reproducibility
0.01～0. 6
Note: X is the average of two independent results obtained from different laboratories. A11 Report
Reproducibility
0.01172×X
Take the arithmetic mean of the two repeated measurement results as the measurement result of the sample, accurate to 0.01%(V/V). Appendix B
(Standard Appendix)
Determination of water content in denatured fuel ethanol (Karl Fischer titration method)
B1 Scope
%(m/m)
B7.1 This method is suitable for determining a wide range of water content in denatured fuel ethanol. By selecting appropriate injection volume, Karl Fischer reagent concentration and automatic titrator, the minimum water content in the sample can be detected to a few parts per million. B1.2 This method uses pyridine-free Karl Fischer reagent and automatic titrator, and determines its titration endpoint by voltage (or current). B2 Method Summary
Pyridine-free Karl Fischer reagent [composed of iodine, sulfur dioxide, methanol and organic base (such as imidazole)] can react quantitatively with any form of water (free water or crystal water) present in the sample. The reaction formula is as follows: H,O+I +SO +R'OH+3RN -(RNH)SO,R' +2(RNH)I Where: R'OH alcohols (such as methanol, ethylene glycol); RV organic bases (such as imidazole).
Use the pyridine-free Karl Fischer reagent to calibrate the known content of water, and obtain the milligrams of water equivalent to 1mL of Karl Fischer reagent (water equivalent), and then use the pyridine-free Karl Fischer reagent to titrate the sample. This standard uses an automatic Karl Fischer titrator, and the titration end point is determined by the sudden decrease in voltage (or sudden increase in current) between the positive and negative platinum electrodes. 97
GB 18350---2001
Note: Karl Fischer reagent contains several toxic substances, such as iodine, sulfur dioxide, organic bases, methanol, etc., so the reagent must be measured in a fume hood and be cautious to prevent inhalation or contact with the skin.
B3 Instruments
B3.1 Automatic Karl Fischer Titrator
B3.1.1 Karl Fischer titrator should be able to "start titration" the moment the sample enters the titration container, and can automatically determine the titration end point. When using pyridine-free Karl Fischer reagent and measuring by voltage (or current) end point method, the sensitivity should be less than 0.01mg water. B3.1.2 The titration device should be sealed and have moisture-proof drying facilities, and can automatically monitor the moisture in the environment and make corrections. B3.1.3 The titrator can automatically supply reagents and discharge waste liquid, and has an automatic stirring device. The platinum electrode in the titration container should be kept clean and sensitive. B3. 1.4
B3.1.5 When injecting samples by mass method, a 1/10,000 electronic balance that matches the instrument should be equipped. B3.2 Micro syringe: 25μL50μL, B3.3 Micropipette or pipette: 1mL, 2ml.5mL. B4 Reagents and Solutions
The reagents used in this test method are analytically pure unless otherwise specified. B4.1 Methanol: Meet the requirements of GB/T683, and the water content should be less than 0.05% (m/m). If the water content in the reagent is greater than 0.05% (m/m), add about 50g of 5A molecular sieve to 500mL of methanol, plug the bottle, leave it overnight, and absorb the upper clear liquid for use. B4.2 Pyridine-free Karl Fischer reagent: water equivalent 3~5mgH20/mL. B4.3 Water standard solution: Use water that meets the second level and above specifications in GB/T6682-1992. It can also be made by distilling ordinary distilled water through a quartz sub-boiling water distiller.
B4.4 Water-methanol standard solution (1 mL of solution contains 10 mg of water): Use a pipette to accurately draw 1.00 mL of water standard solution, inject it into a 100 mL volumetric flask that has been pre-filled with about 50 mL of methanol solvent and is fully dried, make up to volume with methanol, mix and set aside. B5 Operation steps
B5.1 Install and debug the instrument according to the operating instructions of the automatic Karl Fischer titrator. B5.2 Calibration of Karl Fischer reagent
B5.2.1 Karl Fischer reagent needs to be calibrated daily. B5.2.2 Either water standard solution or water-methanol standard solution can be used for calibration. B5.2.3 Draw 25 ml to 50 ml of methanol or other suitable solvent and add it to a water-free, clean titration container, and perform pre-titration of the solvent according to the operating instructions of the titrator until the titration end point. B5.2.4 Weigh the water standard solution by mass method or absorb the water-methanol standard solution by volume method a) Weigh the water standard solution by mass method
Use a micro syringe to absorb about 20l of water standard solution, remove the water attached to the outside of the needle with filter paper, and weigh it in the analytical balance matched with the instrument, then quickly open the plug of the injection port and inject it into the titration container (Note: the last drop of water should be sucked back into the needle tube and should not remain outside the needle), put the micro syringe back into the analytical balance and weigh it, and use the reduction method to weigh the actual mass of the water standard solution added, accurate to 0.0001g, and input it into the instrument, set and start the parameters and program for water calibration to perform automatic titration until the end point. The consumption of Karl Fischer reagent and the water equivalent result will be automatically displayed or printed out. b) Absorb water-methanol standard solution by volume method: Use a pipette to accurately absorb 2.00ml of water-methanol standard solution, quickly open the plug of the injection port, and inject it into the titration container. Set and start the parameters and program for calibration with water-methanol standard solution to automatically titrate until the end point. The consumption of Karl-Feiß reagent and the water content will be automatically displayed or printed out. 98
B5.3 Determination
GB 18350---2001
According to the water content in the sample, accurately sample [-Generally, when the water content is about 0.5% (m/m), 2.00ml can be sampled; if the water content is about 0.2% (m/m), 5.00ml can be sampled]. As in the calibration, first measure 25mL~50mL of methanol or the selected reagent and inject it into the titration bottle. According to the requirements of the instrument operating manual, start the sample determination program and titrate with Karl-Feiß reagent until the end point. The volume of Karl Fischer reagent consumed and the water content of the sample will be automatically displayed and printed out in % (m/m). B6 Calculation
B6.1 The water equivalent (T) of Karl Fischer reagent can be calculated according to formula (B1) and (B2): T=
Where: T---the water equivalent of Karl Fischer reagent, mgH.O/mL; m,--the mass of water injected into the titration bottle, mg; C---the mass of water contained in each milliliter of water-methanol standard solution, mg/mL. V,--the volume of water-methanol standard solution injected into the titration bottle, mL; V.--the volume of Karl Fischer reagent consumed during calibration, mI. B6.2 The water content in the sample can be calculated according to formula (B3): X, =: - V.) XX 0.001 × 100 (V/- Ve) ×T × 0. 001 × 100 Vxp
Wherein: X,-
. Water content in the sample, % (m/m);
The volume of Karl Fischer reagent consumed when titrating the sample, mL; The volume of Karl Fischer reagent consumed when titrating the reagent blank, mL; T. The water equivalent of Karl Fischer reagent, mgH,O/mL; Sampling volume, mL;
Density of the sample + g/cm;
Sampling volume·.
B6.3 When converting the mass percentage into volume percentage, calculate according to formula (B4): Xa=
Wherein, X...
Water content in the sample, %(V/V);
X,-Water content in the sample, %(m/m);\-Density of the sample at 20C g/cm";-Density of water at 20C.g/cm.
B7 Precision (95% confidence level)
(B1)
- B3 )
（B4)
Repeatability: In the same laboratory, the same analyst uses the same instrument to analyze the same sample. The difference between the two results obtained by repeated measurements should not exceed 0.008% (V/V).
Reproducibility: In different laboratories, the difference between the two results obtained by different analysts for the same sample should not exceed 0.061% (V/V). B8 Report
Take the arithmetic mean of the two repeated measurement results as the moisture content in the sample, accurate to 0.01% (V/V). 994 Water-methanol standard solution (1 mL of solution contains 10 mg of water): Use a pipette to accurately draw 1.00 mL of water standard solution, inject it into a 100 mL volumetric flask that has been pre-filled with about 50 mL of methanol solvent and fully dried, make up to volume with methanol, mix and set aside. B5 Operation steps
B5.1 Install and debug the instrument according to the operating instructions of the automatic Karl Fischer titrator. B5.2 Calibration of Karl Fischer reagent
B5.2.1 Karl Fischer reagent needs to be calibrated daily. B5.2.2 Either water standard solution or water-methanol standard solution can be used for calibration. B5.2.3 Pipette 25 ml to 50 ml of methanol or other suitable solvent and add it to a water-free, clean titration container, and perform pre-titration of the solvent according to the operating instructions of the titrator until the titration end point. B5.2.4 Weigh the water standard solution by mass method or absorb the water-methanol standard solution by volume method a) Weigh the water standard solution by mass method
Use a micro syringe to absorb about 20l of water standard solution, remove the water attached to the outside of the needle with filter paper, and weigh it in the analytical balance matched with the instrument, then quickly open the plug of the injection port and inject it into the titration container (Note: the last drop of water should be sucked back into the needle tube and should not remain outside the needle), put the micro syringe back into the analytical balance and weigh it, and use the reduction method to weigh the actual mass of the water standard solution added, accurate to 0.0001g, and input it into the instrument, set and start the parameters and program for water calibration to perform automatic titration until the end point. The consumption of Karl Fischer reagent and the water equivalent result will be automatically displayed or printed out. b) Absorb water-methanol standard solution by volume method: Use a pipette to accurately absorb 2.00ml of water-methanol standard solution, quickly open the plug of the injection port, and inject it into the titration container. Set and start the parameters and program for calibration with water-methanol standard solution to automatically titrate until the end point. The consumption of Karl-Feiß reagent and the water content will be automatically displayed or printed out. 98
B5.3 Determination
GB 18350---2001
According to the water content in the sample, accurately sample [-Generally, when the water content is about 0.5% (m/m), 2.00ml can be sampled; if the water content is about 0.2% (m/m), 5.00ml can be sampled]. As in the calibration, first measure 25mL~50mL of methanol or the selected reagent and inject it into the titration bottle. According to the requirements of the instrument operating manual, start the sample determination program and titrate with Karl-Feiß reagent until the end point. The volume of Karl Fischer reagent consumed and the water content of the sample will be automatically displayed and printed out in % (m/m). B6 Calculation
B6.1 The water equivalent (T) of Karl Fischer reagent can be calculated according to formula (B1) and (B2): T=
Where: T---the water equivalent of Karl Fischer reagent, mgH.O/mL; m,--the mass of water injected into the titration bottle, mg; C---the mass of water contained in each milliliter of water-methanol standard solution, mg/mL. V,--the volume of water-methanol standard solution injected into the titration bottle, mL; V.--the volume of Karl Fischer reagent consumed during calibration, mI. B6.2 The water content in the sample can be calculated according to formula (B3): X, =: - V.) XX 0.001 × 100 (V/- Ve) ×T × 0. 001 × 100 Vxp
Wherein: X,-
. Water content in the sample, % (m/m);
The volume of Karl Fischer reagent consumed when titrating the sample, mL; The volume of Karl Fischer reagent consumed when titrating the reagent blank, mL; T. The water equivalent of Karl Fischer reagent, mgH,O/mL; Sampling volume, mL;
Density of the sample + g/cm;
Sampling volume·.
B6.3 When converting the mass percentage into volume percentage, calculate according to formula (B4): Xa=
Wherein, X...
Water content in the sample, %(V/V);
X,-Water content in the sample, %(m/m);\-Density of the sample at 20C g/cm";-Density of water at 20C.g/cm.
B7 Precision (95% confidence level)
(B1)
- B3 )
（B4)
Repeatability: In the same laboratory, the same analyst uses the same instrument to analyze the same sample. The difference between the two results obtained by repeated measurements should not exceed 0.008% (V/V).
Reproducibility: In different laboratories, the difference between the two results obtained by different analysts for the same sample should not exceed 0.061% (V/V). B8 Report
Take the arithmetic mean of the two repeated measurement results as the moisture content in the sample, accurate to 0.01% (V/V). 994 Water-methanol standard solution (1 mL of solution contains 10 mg of water): Use a pipette to accurately draw 1.00 mL of water standard solution, inject it into a 100 mL volumetric flask that has been pre-filled with about 50 mL of methanol solvent and fully dried, make up to volume with methanol, mix and set aside. B5 Operation steps
B5.1 Install and debug the instrument according to the operating instructions of the automatic Karl Fischer titrator. B5.2 Calibration of Karl Fischer reagent
B5.2.1 Karl Fischer reagent needs to be calibrated daily. B5.2.2 Either water standard solution or water-methanol standard solution can be used for calibration. B5.2.3 Pipette 25 ml to 50 ml of methanol or other suitable solvent and add it to a water-free, clean titration container, and perform pre-titration of the solvent according to the operating instructions of the titrator until the titration end point. B5.2.4 Weigh the water standard solution by mass method or absorb the water-methanol standard solution by volume method a) Weigh the water standard solution by mass method
Use a micro syringe to absorb about 20l of water standard solution, remove the water attached to the outside of the needle with filter paper, and weigh it in the analytical balance matched with the instrument, then quickly open the plug of the injection port and inject it into the titration container (Note: the last drop of water should be sucked back into the needle tube and should not remain outside the needle), put the micro syringe back into the analytical balance and weigh it, and use the reduction method to weigh the actual mass of the water standard solution added, accurate to 0.0001g, and input it into the instrument, set and start the parameters and program for water calibration to perform automatic titration until the end point. The consumption of Karl Fischer reagent and the water equivalent result will be automatically displayed or printed out. b) Absorb water-methanol standard solution by volume method: Use a pipette to accurately absorb 2.00ml of water-methanol standard solution, quickly open the plug of the injection port, and inject it into the titration container. Set and start the parameters and program for calibration with water-methanol standard solution to automatically titrate until the end point. The consumption of Karl-Feiß reagent and the water content will be automatically displayed or printed out. 98
B5.3 Determination
GB 18350---2001
According to the water content in the sample, accurately sample [-Generally, when the water content is about 0.5% (m/m), 2.00ml can be sampled; if the water content is about 0.2% (m/m), 5.00ml can be sampled]. As in the calibration, first measure 25mL~50mL of methanol or the selected reagent and inject it into the titration bottle. According to the requirements of the instrument operating manual, start the sample determination program and titrate with Karl-Feiß reagent until the end point. The volume of Karl Fischer reagent consumed and the water content of the sample will be automatically displayed and printed out in % (m/m). B6 Calculation
B6.1 The water equivalent (T) of Karl Fischer reagent can be calculated according to formula (B1) and (B2): T=
Where: T---the water equivalent of Karl Fischer reagent, mgH.O/mL; m,--the mass of water injected into the titration bottle, mg; C---the mass of water contained in each milliliter of water-methanol standard solution, mg/mL. V,--the volume of water-methanol standard solution injected into the titration bottle, mL; V.--the volume of Karl Fischer reagent consumed during calibration, mI. B6.2 The water content in the sample can be calculated according to formula (B3): X, =: - V.) XX 0.001 × 100 (V/- Ve) ×T × 0. 001 × 100 Vxp
Wherein: X,-
. Water content in the sample, % (m/m);
The volume of Karl Fischer reagent consumed when titrating the sample, mL; The volume of Karl Fischer reagent consumed when titrating the reagent blank, mL; T. The water equivalent of Karl Fischer reagent, mgH,O/mL; Sampling volume, mL;
Density of the sample + g/cm;
Sampling volume·.
B6.3 When converting the mass percentage into volume percentage, calculate according to formula (B4): Xa=
Wherein, X...
Water content in the sample, %(V/V);
X,-Water content in the sample, %(m/m);\-Density of the sample at 20C g/cm";-Density of water at 20C.g/cm.
B7 Precision (95% confidence level)
(B1)
- B3 )
（B4)
Repeatability: In the same laboratory, the same analyst uses the same instrument to analyze the same sample. The difference between the two results obtained by repeated measurements should not exceed 0.008% (V/V).
Reproducibility: In different laboratories, the difference between the two results obtained by different analysts for the same sample should not exceed 0.061% (V/V). B8 Report
Take the arithmetic mean of the two repeated measurement results as the moisture content in the sample, accurate to 0.01% (V/V). 99- the moisture content in a sample, % (m/m); \- the density of the sample at 20C, g/cm"; - the density of water at 20C, g/cm.
B7 Precision (95% confidence level)
(B1)
- B3)
(B4)
Repeatability: In the same laboratory, the same analyst uses the same instrument to analyze the same sample. The difference between the two results obtained by repeated measurements should not exceed 0.008% (V/V).
Reproducibility: In different laboratories, the difference between the two results of the same sample analyzed by different analysts should not exceed 0.061% (V/V). B8 Report
Take the arithmetic mean of the two repeated measurement results as the moisture content in the sample, accurate to 0.01% (V/V). 99- the moisture content in a sample, % (m/m); \- the density of the sample at 20C, g/cm"; - the density of water at 20C, g/cm.
B7 Precision (95% confidence level)
(B1)
- B3)
(B4)
Repeatability: In the same laboratory, the same analyst uses the same instrument to analyze the same sample. The difference between the two results obtained by repeated measurements should not exceed 0.008% (V/V).
Reproducibility: In different laboratories, the difference between the two results of the same sample analyzed by different analysts should not exceed 0.061% (V/V). B8 Report
Take the arithmetic mean of the two repeated measurement results as the moisture content in the sample, accurate to 0.01% (V/V). 99
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