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GB 23200.16-2016: Food safety national standard -- Determination of ethephon residues in fruits and vegetables -- Liquid chromatographic method
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Food safety national standard -- Determination of ethephon residues in fruits and vegetables -- Liquid chromatographic method
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GB 23200.16-2016
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Basic data | Standard ID | GB 23200.16-2016 (GB23200.16-2016) | | Description (Translated English) | Food safety national standard -- Determination of ethephon residues in fruits and vegetables -- Liquid chromatographic method | | Sector / Industry | National Standard | | Classification of Chinese Standard | G25 | | Word Count Estimation | 9,912 | | Date of Issue | 2016-12-18 | | Date of Implementation | 2017-06-18 | | Older Standard (superseded by this standard) | NY/T 1016-2006 | | Regulation (derived from) | State Health Commission, Ministry of Agriculture, Food and Drug Administration Notice No. 16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 23200.16-2016: Food safety national standard -- Determination of ethephon residues in fruits and vegetables -- Liquid chromatographic method
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Food safety national standard - Determination of ethephon residues in fruits and vegetables - Liquid chromatographic method
National Standards of People's Republic of China
GB
Instead of NY/T 1016-2006
National standards for food safety
Determination of ethephon residues in fruits and vegetables
Gas chromatography
National food safety standards-
Determination of ethephon residue in fruits and vegetables
Gas chromatography
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 NY/T 1016-2006 "Determination of ethephon residues in vegetables by gas chromatography".
This standard and GB/T 5009.7-2008 compared to the main changes are as follows.
- modified in accordance with the format of food safety standards;
- normative reference documents to increase the GB 2763 "maximum pesticide residues in food" standard;
- the preparation of the sample to increase the sampling site requirements and refine the requirements of the preparation of the sample;
- Increased precision requirements.
National standards for food safety
Determination of ethephon residues in fruits and vegetables - Gas chromatographic method
1 Scope
This standard specifies the determination of ethephon residues in fruits and vegetables.
This standard is applicable to the analysis of ethephon residues in fruits and vegetables.
2 normative reference documents
The following documents are indispensable for the application of this document. For dated filing applications, only the dated edition applies to this document.
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
Extraction of ethephon from the sample with methanol and derivatization of dimethylethylenediethanoxide by diazomethane with a flame photometric detector (phosphor filter)
The gas chromatograph was determined by external standard method.
4 reagents and materials
Unless otherwise stated, only chromatographic pure reagents are used in the analysis, and water is the primary water specified in GB/T 6682.
4.1 Reagents
4.1.1 Potassium hydroxide (KOH).
4.1.2 Hydrochloric acid (HCl).
4.1.3 Methanol (CH3OH).
4.1.4 anhydrous ether (C2H6O).
4.2 solution preparation
Methanol - hydrochloric acid solution (90 10). take 90mL of methanol added to 10mL hydrochloric acid, and mix.
4.3 standards
Ethephon standard, purity ≥ 95%.
4.4 standard solution preparation
4.4.1 ethephon standard solution. accurately weighed the amount of ethephon standard, with methanol prepared into a mass concentration of 1000 mg/L standard storage
Preparation of liquid. According to the need to dilute the standard stock solution with methanol to prepare the appropriate concentration of standard working fluid, the preparation process requires polyethylene containers.
4.4.2 Diazomethane solution. see Appendix A.
5 instruments
5.1 gas chromatograph and equipped with flame photometric detector.
5.2 Ultrasonic cleaner.
5.3 Tissue crusher.
5.4 nitrogen dryers.
6 Analysis steps
6.1 Preparation of the sample
The samples of vegetables and fruit samples shall be sampled according to the provisions of Appendix A of GB 2763, and the whole sample shall be processed for the smaller samples.
For a larger, substantially uniform sample, it can be divided or cut into small pieces on a symmetry or symmetry plane; for slender, flat or component
Samples in different parts of the sample can be cut in different parts of small pieces or cut into small pieces or processing; take the sample after its chopped, fully mixed
Uniform, with a quartile sampling or directly into the tissue crusher mashed into homogenate, into the polyethylene bottle in the -16 ℃ ~ -20 ℃ under the conditions of preservation.
6.2 Extraction
Weigh the sample 10 g (accurate to 0.01g) in the polyethylene beaker, add 0.5 mL of methanol - hydrochloric acid solution and 50 mL of methanol, ultrasound
Shock extraction 5min, filtered in 100 mL of polyethylene volumetric flask, the residue and then 30 mL of methanol extraction time, combined with the extraction of polyethylene
Capacity bottle, the volume of 100 mL.
6.3 Derivatization
Accurately absorb 10 mL of the above volume solution into the 15 mL polyethylene centrifuge tube, in a dry nitrogen flow on the 30 ℃ ~ 35 ℃ water bath
Concentrated to about 1.5 mL, add 0.5 mL of methanol - hydrochloric acid solution and 8 mL of anhydrous ether, mixed well, placed 10 min, the supernatant
Into another polyethylene centrifuge tube, the residual solution with 1 mL of anhydrous ether extraction 2 times, the extract into the above solution, at 30 ℃ ~ 35 ℃
Concentrate to about 1 mL in a water bath. In the fume hood, dropping the diazomethane solution into the concentrate until the yellow does not fade. Cover the claws,
Placed for 15 min. Concentrated in a nitrogen stream at 30 ° C to 35 ° C to about 1 mL, diluted with ether to 2.00 mL, and analyzed by gas chromatography.
6.4 Derivation of standard solutions
Take the appropriate amount of ethephon standard working solution (10.0 mL with methanol), follow the sample extraction and derivatization steps (5.2 and 5.3)
To operate.
6.5 Gas Chromatographic Reference Conditions
Column. FFAP 30 m x 0.32 mm (id) x 0.25 μm Elastic quartz capillary column or quite polar column.
Carrier gas. nitrogen, flow rate 2.5 mL/min, purity ≥99.999%;
Gas. hydrogen, flow rate 85 mL/min, purity ≥99.999%;
Gas combustion. air, flow 110 mL/min.
Inlet temperature. 240 ° C;
Heating procedure. 120 ℃ (1min) 40 ℃/min230 ℃ (2min);
Detector temperature 150 ° C.
Detector. Flame photometric detector (phosphor filter).
Injection volume. 1 μL.
6.6 Chromatographic analysis
(5.3 and 5.4) of the standard sample and the sample to be tested, respectively, were injected into a chromatograph,
The sample is compared with the peak area of the standard sample derivative and quantified by external standard method.
6.7 blank test
The following steps (5.2 and 5.3) are carried out except for non-test samples.
7 results calculated
The residual amount of ethephon in the sample is calculated using a chromatographic data processor or according to formula (1)
1000ρ
VmA
VVA
.. (1)
Where.
The residual amount of ethephon in the sample, in milligrams per kilogram (mg/kg);
A chromatographic area of dimethylacetylene in sample solution;
The peak area of dimethyl vinyl chloride in As - standard solution;
The mass concentration of ethephon in the standard solution, in micrograms per milliliter (μg/mL);
V-extraction solvent volume, in milliliters (mL);
V1 - fractional volume in milliliters (mL);
V2 - on the machine volume volume, in milliliters (mL);
M-Weigh the quality of the sample in grams.
The calculated results shall be deducted from the blank values and the calculated results shall be the arithmetic mean of the two independent determinations obtained under reproducible conditions
Show that two valid digits are reserved.
8 precision
The ratio of the absolute difference between the two independent determinations obtained under reproducibility and its arithmetic mean (percentage) shall be in accordance with the
Record B requirements.
The ratio of the absolute difference between the two independent determinations obtained under reproducibility and its arithmetic mean (percentage) shall be in accordance with the
Record C requirements.
9 limit of quantification
The limit of quantification for this standard method is 0.03 mg/kg.
10 Chromatogram Reference
The chromatogram of ethephon at a concentration of 0.05 mg/L is shown in Fig.
Appendix A
(Normative appendix)
Diazomethane
Preparation of A1 2 - nitroso - 2 - methylurea
In a 250 mL flask, add 13.5 g of methylamine hydrochloride, add 67 g of water, add 40.2 g of urine, slowly reflux for 2 h 45 min
After vigorous reflux for 15 min, cooled to room temperature, 20.2 g of sodium nitrite was added and the solution was cooled to 0 ° C. 80 g of ice was added to a 1 L beaker,
And cooled in an ice-salt bath, then 13.3 g of sulfuric acid was added and the methylurea-nitrite was just added with stirring so that the temperature did not exceed
0 ° C, about 1 h plus finished. Nitrosomethylurea into a crystalline foam floating on top, immediately by suction filtration and well dry, and then
A small amount of ice water washing, the resulting crystal into a vacuum dryer drying, the temperature does not exceed 4 ℃.
Preparation of A2 Diazomethane
In a 500 mL round bottom flask, 60 mL of 50% sodium hydroxide solution and.200 mL of ether were placed and the mixture was cooled to 0 ° C and then shaken
And 20.6 g of 2-nitrous acid-2-methylurea was added thereto, and the flask was charged with a condenser tube for distillation. The lower end of the condenser pipe is connected with a receiving pipe,
Through a double-hole rubber stopper immersed in a 250 mL Erlenmeyer flask in 40 mL of ether, the conical flask was placed in an ice-salt bath to cool and release
The resulting gas was passed through a second 40 mL of diethyl ether, which was similarly cooled to below 0 ° C, and the reaction flask was placed on a water bath at 50 ° C
The boiling point of the ether, and shake from time to time, the distilled ether until the distillate color becomes colorless, usually 2/3 of the ether after distilling off
Becomes colorless. The ether can not be evaporated in any case and the ether solution in the receiver is combined with 5.3 g to 5.9 g of diazomethane.
Appendix B
(Normative appendix)
Laboratory repeatability requirements
Table B.1 Laboratory repeatability requirements
Measured component content
Mg/kg
Precision
0.001 36
> 0.01
> 1 14
Appendix C
(Normative appendix)
Inter-laboratory reproducibility requirements
Table C.1 Inter-laboratory reproducibility requirements
Measured component content
Mg/kg
Precision
0.001 54
> 0.01
> 1 19
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