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GB 23200.44-2016: Food safety national standard -- Determination of carbon disulfide, carbon tetrachloride and dibromoethane residues in grain
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Food safety national standard -- Determination of carbon disulfide, carbon tetrachloride and dibromoethane residues in grain
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GB 23200.44-2016
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Basic data | Standard ID | GB 23200.44-2016 (GB23200.44-2016) | | Description (Translated English) | Food safety national standard -- Determination of carbon disulfide, carbon tetrachloride and dibromoethane residues in grain | | Sector / Industry | National Standard | | Classification of Chinese Standard | G25 | | Word Count Estimation | 9,974 | | Date of Issue | 2016-12-18 | | Date of Implementation | 2017-06-18 | | Older Standard (superseded by this standard) | SN 0353-1995 | | Regulation (derived from) | State Health Commission, Ministry of Agriculture, Food and Drug Administration Notice No. 16 of 2016 | | Issuing agency(ies) | National Health and Family Planning Commission of the People's Republic of China, State Food and Drug Administration | GB 23200.44-2016: Food safety national standard -- Determination of carbon disulfide, carbon tetrachloride and dibromoethane residues in grain
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Food safety national standard - Determination of carbon disulfide, carbon tetrachloride and dibromoethane residues in grain
National Standards of People's Republic of China
GB
Instead of SN 0353-1995
National standards for food safety
Grain in the presence of carbon disulfide, carbon tetrachloride, dibromoethane residues
The amount of detection method
National food safety standards-
Determination of carbon disulfide, carbon tetrachloride
And ethylene dibromide residues in cereals
2016-12-18 Release.2017-06-18 Implementation
National Health and Family Planning Commission of the People 's Republic of China
Issued by the Ministry of Agriculture of the People 's Republic of China
State Administration of Food and Drug Administration
Foreword
This standard replaces SN 0355-95 "Method for the determination of carbon disulfide, carbon tetrachloride and dibromoethane residues in export cereals".
This standard compared with SN 0355-95, the main changes are as follows.
- Standard text format is modified to national standard text format for food safety;
- the name of the "export grain" to "grain";
- increase the "other food reference implementation" in the standard range.
This standard replaced the previous version of the standard release.
-SN 0353-95.
National standards for food safety
Determination of carbon disulfide, carbon tetrachloride and dibromoethane residues in grain
1 Scope
This standard specifies the sample preparation of carbon disulfide, carbon tetrachloride and dibromoethane residues in grain and gas chromatographic method.
This standard applies to the determination of carbon disulfide, carbon tetrachloride and dibromoethane residues in maize, and other foodstuffs can be used for reference.
2 normative reference documents
The following documents are indispensable for the application of this document. For dated references, only the dated edition applies to this
file. For undated references, the latest edition (including all modifications) applies to this document.
GB 2763 National Standard for Food Safety - Maximum Residue Limit of Pesticides in Foodstuffs
GB/T 6682 Analytical laboratory water specifications and test methods
3 principle
The sample was heated and azeotroped with the isooctane and sulfuric acid solution in a distillation extractor. Carbon disulfide, carbon tetrachloride, dibromoethane and isooctane,
The water vapor is distilled off and cooled, and the isooctane extract is separated from water in a collection tube of a distillation extractor. The extract is fixed after dehydration.
It was determined by gas chromatograph with electron capture detector and quantified by external standard method.
4 reagents and materials
4.1 Reagents
4.1.1 distilled water. boiled before use for 20min, cooling standby. Take 300 ml of distilled water in a flask of a distillation extractor (see figure below)
Add 15 ml of isooctane, according to the extraction step (7.1) operation. Under the specified chromatographic conditions, 1 l of the isooctane extract was chromatographed,
Should be the same as the octane other than the chromatographic peaks.
4.1.2 Isooctane (C8H18). analytical grade, in the same chromatographic conditions with the determination of injection 1ul for chromatography, should be no octane
Other than the peaks.
Note. Isooctane purification. 1000ml flask by adding 500ml isooctane, and then add metal sodium tablets 5-10g, connected to the grinding of the condenser, reflux 6-8h, and then use
The whole glass distiller was distilled to collect fractions between 97.5 and 99.5 ° C.
4.1.3 anhydrous sodium sulfate (Na2SO4). analysis of pure, 650 ℃ burning 4h, after cooling stored in a closed container.
4.1.4 concentrated sulfuric acid (H2SO4). analytical grade.
4.1.5 sulfuric acid aqueous solution. 10% (V/V).
4.1.6 Carbon disulfide (CS2). Analytical pure (d
1.263)
4.1.7 Carbon tetrachloride (CCl4). Analytical purity (d
1.594)
4.1.8 Dibromoethane (C2H4Br2). Analytical pure (d
2.177)
4.2 standard solution preparation
4.2.1 Standard stock solution. accurately measure the appropriate volume of carbon disulfide, carbon tetrachloride, dibromoethane, and weigh the weight
Calculate, with isooctane, respectively, with the concentration of 1.00mg/ml of the standard stock solution.
4.2.2 standard working solution
If necessary, standard stock solutions are diluted with isooctane to form a mixed standard working solution at the following concentrations (Table 1).
5 instruments and equipment
5.1 Gas Chromatograph. Equipped with an electron capture detector.
5.2 Distillation extractor (see figure).
5.3 Microinjector. 10ul or 5ul.
5.4 capacity bottle. 25ml.
5.5 anhydrous sodium sulfate column. cylindrical funnel, 22mm (diameter) built-in 5cm high anhydrous sodium sulfate (4.3).
5.6 electric sets. thermostat type, 500ml,.200w.
5.7 All glass system distillation unit.
5.8 Analytical balance. 0.01 g and 0.0001 g.
6 Preparation and storage of samples
6.1 Preparation of the sample
The samples taken, the sampling site according to GB 2763 Appendix A implementation, with a sub-sampling device or quadruple to 1kg, all grinding and through 20
Mesh sieve, mix, are divided into two, immediately into the clean container, sealed, marked mark.
6.2 Sample storage
Store the sample below 0 ° C.
Note. ① shrink the sample, the operation should be as fast as possible to prevent the loss of fumigant.
During the operation of the sample preparation, it is necessary to prevent the sample from being contaminated or the change in the content of the residue.
7 Analysis steps
7.1 Extraction
A sulfuric acid aqueous solution (10%, V/V) was added to the return port from the receiving tube of the distillation extractor and the gas inlet. even
Connect the condenser and gas absorption wells, add 5 mL of isooctane from the mouth of the condenser to the gas absorption trap. Access to cooling water. Quickly take the mix
50.0 g (accurate to 0.1 g) of the sample was placed in a flask to connect the flask and extractor. Add 12 mL of isooctane from the flotation port of the flask
300 m1 sulfuric acid aqueous solution (10%, V/V). Close the dosing port and seal the dosing with a small amount of sulfuric acid solution (10%, V/V). Will be used to heat sets
The flask was heated and the isooctane extract was slowly distilled off until the isooctane extract was completely distilled off and heated for about 5 minutes. stop
Heat the flask to cool. The aqueous layer in the receiving tube was released from the lower mouth and then the isooctane extract was passed through an anhydrous sodium sulfate column and collected
25 mL volumetric flask. From the upper surface of the condenser, rinse the condenser, gas absorption trap, receiver tube and anhydrous sulfur with about 7 mL of isooctane
Sodium sulphate column, lotion into the volumetric flask, with isooctane capacity, gas chromatographic determination.
7.2 Determination
7.2.1 Gas Chromatographic Reference Conditions
A) Column. glass column, 1.6 m X3.2 m m (inner diameter), filler 25% (m/m) DC-200 applied to Chromosorb W
AW-DMCS (60-80 mesh).
B) Column temperature. 75 ° C.
C) Inlet temperature. 150 ° C.
D) Detector temperature. 150 ° C.
E) helium, purity ≥99.99%, 25m L/min.
7.2.2 Chromatographic determination
According to the sample solution of carbon disulfide, carbon tetrachloride, dibromoethane content, selected peak height similar to the standard working solution. Standard working solution
And carbon tetrachloride, carbon tetrachloride and dibromoethane in the sample solution should be within the linear range of the instrument. On the standard working solution and sample solution
Measurement of volume injection. Under the above chromatographic conditions, the retention times of carbon disulfide, carbon tetrachloride and dibromoethane were 1.7 m in, 3.5
Min, 8.1 min.
7.3 blank experiment
In addition to the sample, according to the above steps.
8 results are calculated and expressed
With a chromatographic data processor or according to formula (2).
Where. residual amount of carbon disulfide or carbon tetrachloride or dibromoethane in the X-sample, mg/kg;
H-peak concentration of carbon disulfide or carbon tetrachloride or dibromoethane in the sample solution, mm;
H - standard working fluid with carbon disulfide or carbon tetrachloride or dibromoethane peak height, mm;
C in a standard working solution of carbon disulfide, carbon tetrachloride, dibromoethane concentration, ug/mL;
V - the final volume of the sample solution, mL;
M - the amount of sample weighed, g.
Note. The result of the calculation shall be deducted from the blank value. The result of the measurement shall be expressed as the arithmetic mean of the parallel measurement, and two valid digits shall be retained.
9 precision
9.1 The ratio of the absolute difference between the two independent determinations obtained under reproducibility and its arithmetic mean (percentage) shall be in accordance with
Appendix A requirements.
9.2 The ratio of the absolute difference between the two independent determinations obtained under reproducibility and its arithmetic mean (percentage) shall be in accordance with
Appendix B requirements.
10% limit and recovery rate
10.1 Quantitation limits
The quantification limit of this method is. carbon disulfide. 0.02 mg/kg; carbon tetrachloride. 0.004 mg/kg; dibromoethane. 0.005 mg/kg.
10.2 Recovery rate
The recovery of this method is shown in Table 2.
Appendix A
(Normative appendix)
Laboratory repeatability requirements
Table A.1 Laboratory repeatability requirements
Measured component content
Mg/kg
Precision
0.001 36
> 0.01
> 1 14
Appendix B
(Normative appendix)
Inter-laboratory reproducibility requirements
Table B.1 Inter-laboratory reproducibility requirements
Measured component content
Mg/kg
Precision
0.001 54
> 0.01
> 1 19
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