GB/T 3144-1982 Gas chromatography determination of hydrocarbon impurities in toluene GB/T3144-1982 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Gas Chromatographic Determination of Hydrocarbon Impuritles in Toluene, Toluene-determfnation of hydrocarbon impuritles-gaschromatographic method
UDC668.735.2
: 543.541
GB3144-82
This standard is formulated with reference to ISO5279. It is applicable to the determination of hydrocarbon impurities in toluene. These include benzene, C-slice hydrocarbons and non-aromatic hydrocarbons of straight-base F-nonane. The measurement range for each group of impurities is 0.01～1.00% (mass ratio). 1 Method Overview
Add a known amount of internal standard to the sample, take a certain amount of the mixture with a syringe and inject it into the vaporization chamber of the chromatograph, the vaporized mixture is carried into the chromatographic column by the carrier gas, and each component flowing out is detected by the flame ionization detector, and the chromatogram is recorded on the recorder. The relative retention time of the impurity is used for qualitative analysis, and the chromatographic peak area of ​​the impurity relative to the internal standard is used for maximum analysis. The relative calibration factors of the detector for each component should be considered in the calculation. 2 Instruments and Materials
2.F Instruments
2.1.1 Chromatograph: Any type of chromatograph with flame ionization detector that can meet the test conditions. The instrument should have sufficient sensitivity to obtain a peak height of at least twice the noise for a mixture containing 0.005% (mass ratio) of ethyl acetate under the specified test conditions.
2.1.2 Analytical column: Sensitivity is 1/1000 g. 2.1.3 Syringes: 1 μl, 10 μl, 50 μl, 10 ml and 50 ml. 2.1.4 Chromatographic column: Made of stainless steel tube, copper tube, aluminum tube or glass tube, 4 meters long and 2 mm inner diameter. 2.2 Materials
2.2.1 Bottle with cold volume: 10 ml.
2.2.2 Oxygen: Oxygen content is not more than 0.0005% (volume ratio). 2.2.3 Nitrogen.
2.2.4 Slit air.
2.2.5 Oxygen regulator.
2.2.6 Standard sieves, 60 and 80 mesh.
9 Reagents
3.1 n-Hexane
Chromatographic grade (excluding benzene, decane and ethylbenzene). 3.2 Internal standard
n-Decane, purity not less than 99% (mass ratio). 3.3 Standard substancesbzxz.net
Purity not less than 99% (mass ratio).
3.3.1 Benzene.
3.3.2 Toluene.
3.3.8 Ethylbenzene.
Promulgated by the National Bureau of Standards on July 20, 1982
Implemented on March 1, 1983
3.3.4 + -.
3.4 ​​Stationary phase
3.4.1 Polyethylene glycol 1500
3.4.2 6201H phase (60~801).
4 Preparation
4.1 Preparation of stationary phase
GB 3144—82
Weigh 12.3 g of polyethylene glycol 1500 and dissolve it in 50 mM of a suitable solvent (such as alcohol). Add the solution to 37.5 g of 6201 support and stir gently. Use an infrared lamp to slowly bake and evaporate the solvent until the solvent is evaporated. If there is powder on the coated stationary phase, it can be sieved again to remove the powder.
4.2 Filling and aging of the chromatographic column
Plug one end of the chromatographic column with a porous metal mesh or glass wool and connect it to a vacuum recorder. Connect a funnel to the other end and load the prepared phase into the chromatographic column through the funnel. When loading, knock or vibrate the column while pumping air to ensure uniform filling. When the column is filled, remove the chromatographic column and stop the pump. Pour a small amount of phase, and then plug this end with a porous metal mesh or glass wool. Install the chromatographic column on the chromatograph. After testing, pass the carrier gas for aging at a temperature 20 to 50 degrees higher than the operating temperature until the baseline stabilizes to 90°C.
4.3 Performance inspection of chromatographic column
4.3.1 Under the specified test conditions, the chromatographic column should be able to completely separate the internal standard and all other components. 4.3.2 Prepare a mixture containing 0.10% (volume ratio) ethylbenzene. Take 1 microliter of the mixture and inject it into the vaporization chamber of the chromatograph to record the chromatogram. Measure the height from the valley of the two peaks of the intermediate and ethylbenzene to the baseline. The height from the valley of the two peaks to the baseline should not exceed 10% of the height of the ethyl peak. 4.4 Determination of correction factor
4.4.1 Use a syringe to take 10 μl of hexane into a clean, dry, stoppered 10 ml volumetric flask. Use a 50 μl syringe to add 50 μl each of n-hexane, benzene, methylbenzene and ethylbenzene into the volumetric flask in sequence. Weigh the mass of each component by the incremental method to the nearest 0.2 μg.
According to the experimental conditions specified in the specification, after the instrument is stable, inject the above standard sample into the chromatograph and record the chromatogram. 4.4.3 Calculate the relative correction factor of each component according to formula (1): A.ML
Formula: F: Relative correction factor of component A: Peak area of ​​​​the analyte
AL——frontal area of ​​​​the analyte;
M,——mass of the analyte, g;
——mass of n-decane, g.
(1)
If the relative correction factor obtained by the above test steps differs from the typical correction factor given in Table 1 by more than 10 of the given value, it is necessary to recheck with the first standard sample until the difference between the two numbers is less than 10%, and the measured value can be used. Table 1 Typical correction factors
Calibration materials
N-alkanes
Ethylene
Typical correction factors
4,5 Determination of relative retention time
GB-3144--82
4.5.1 Use a syringe to take 10 ml of n-hexane and inject it into a clean, dry, 10 ml volumetric flask with a stopper. Use a 50 μl syringe to inject 50 μl each of n-nonane, benzene, n-decane, toluene, n-decane, methylbenzene, m-, p-toluene, and o-xylene into the flask in turn and mix them evenly.
4.5.2 Under the test conditions specified in Table 3, after the instrument is stable, inject the above standard sample into the chromatograph and record the retention time of each component. Take n-undecane as the benchmark, calculate the relative retention time of each component. Use this relative retention time for qualitative analysis. The typical relative retention time of each component is shown in Table 2.
Table 2. Typical relative retention time of each component
n-undecane
n-decane
n-triphenylbenzene
m-xylene and p-xylene
o-triphenylbenzene
5 Test steps
5.1 Adjust the instrument according to the test conditions specified in Table 3. Table 3 Experimental conditions
Vaporization temperature
Carrier gas (H2O) flow rate
Air flow rate
Tail gas (N2O) flow rate
Injection volume
100★Allow up and down adjustment of 20℃)
180℃ (not lower than the boiling point of the heaviest component) Typical relative retention time
Adjust to the retention time of toluene between 6 and 10 minutes (not more than 15 minutes) Adjust according to the requirements of different instruments and flame ionization detectors. Usually the ratio with carrier gas is 1:10~15
The flow rate ratio with carrier gas is 1:1
1 micro (under the premise of meeting the separation, it can also be injected with large sample) 300 mm! Xiaogang
6.2 Take 20 microliters of n-decane and 10 ml of sample and inject them into the volumetric flask with stopper respectively. Weigh the mass of the alkane and the sample using the incremental method. Weigh to 0.2 mg.
5.3 Under the test conditions specified in Table 3, after the chromatograph is stable, inject 1 microliter of the prepared sample and record the chromatogram (typical chromatogram).
GB 3144-82
Time, minutes 2018161412108
Non-aromatic hydrocarbons
Typical chromatogram of hydrocarbon impurities in toluene
5. Measure the peak area of ​​each impurity and n-decane (internal standard). When measuring manually, measure the peak height and half-peak width. The peak area is obtained by multiplying the peak height by the half-peak width. If a data processor is used, the analysis and calculation program can be pre-programmed for automatic calculation. 6 Calculation
The impurity content is expressed in mass percentage. According to the report requirements, calculate the content of each group of decane, non-aromatic hydrocarbons and C: aromatic hydrocarbons to 0.01%. The calculation formula is as follows:
X=100×A·ML.FL
AL. MO. F
Wherein, X, -
—the mass percentage of component i in the sample; A:—peak area of ​​the component,
AL——peak area of ​​n-decane (internal standard): F——relative calibration factor of component i:
FL—relative calibration factor of n-decane-
MO—mass of sample, g;
(2)
Mass of n-decane (internal standard) used in GB 3144-B2, g. Note: All non-aromatic hydrocarbons adopt relative calibration factors. All C, C and C hydrocarbons are used in relative calibration with ethylbenzene. 7 Precision
The following values ​​are used to judge the reliability of the results (9 confidence level) 1 Repeatability
The difference between two repeated measurements by the same operator should not be greater than the following provisions: 1.01% (mass ratio) for impurity content within the range of 0.01~0.10%; 10% of the arithmetic mean for impurity content within the range of 0.10~1.00%. 7.2 Reproducibility
The difference between the results of two laboratory samples should not be greater than the following provisions: 0.2% (mass ratio) for impurity content within the range of 0.01~0.10%; 20% of the arithmetic mean for impurity content within the range of 0.10~1.00%.
8 Report
Take the arithmetic mean of the two parallel determination results as the hydrocarbon impurity test result in the sample, and report the result to the nearest 0.01 (mass ratio). Additional Notes:
This standard was proposed by the Ministry of Petroleum Industry of the People's Republic of China and is under the technical jurisdiction of the China Petrochemical Research Institute. This standard was drafted by the head of Fushun Petroleum. The main drafter of this standard was Chen Xidian.
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