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GB 23200.18-2016Food safety national standard -- Determination of 15 Substituted Urea Herbicide Residues in Vegetables by Non -- Grass Long and Liquid Chromatography (English PDF)

蔬菜中非草隆等15种取代脲类除草剂残留量的测定液相色谱法

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Issued by

National Health and Family Planning Commission of the People 's Republic of China

Level / Type

National · Mandatory

Issue date

December 18, 2016

Implementation date

June 18, 2017

Scope

GB 23200.18-2016 is the English-translated version of 蔬菜中非草隆等15种取代脲类除草剂残留量的测定液相色谱法.

GB 23200.18-2016 — This standard stipulates that vegetables are not grass-long, Ding thylonon, methomyl dragon, metaprolone, chlorotoluron, fluroxides, isoproturon, diuron, green valley Determination of 15 kinds of substituted ureas herbicides in liquid, such as Long, Bromoglossone, Acetylmethrin, Cyclosulfuron, Liguron, Chlorpromethyl, Method.

This standard applies to the determination of the above 15 kinds of substituted ureas herbicides in vegetables.

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Document preview — GB 23200.18-2016

National Standard of the People's Republic of China

Classification: G 25
Replacing: NY/T 1726-2009

Issued by: National Health and Family Planning Commission of the People 's Republic of China

Foreword
1 Scope
2 Normative reference documents
3 Principle
4 Reagents and materials
4.1 Reagents
4.2 Solution preparation
4.3 Standards
4.4 Standard solution preparation
4.5 Materials
5 Instruments
6 Analysis steps
6.1 Preparation of the sample
6.2 Extraction
6.3 Purification
6.4 Chromatographic reference conditions
6.5 Determination
7 Results calculated
8 Precision
9 Limit of quantification
10 Chromatograms
11 Kerosulfuron buturon 23.474 0.50 0.03
15 Grass less long neburon 29.446 0.50 0.015

Foreword

This standard replaces NY/T 1726-2009 "Determination of 15 kinds of substituted ureas herbicides in vegetables such as non-grassland and other liquid chromatography." this standard is compared with NY/T 1726-2009 as follows.

- the standard name has been modified to increase the national standard for food safety;

- modified in accordance with the format of the food safety standard.

- 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 15 Substituted Urea Herbicide Residues in Vegetables by Non - Grass Long and Liquid Chromatography

1 Scope

This standard stipulates that vegetables are not grass-long, Ding thylonon, methomyl dragon, metaprolone, chlorotoluron, fluroxides, isoproturon, diuron, green valley Determination of 15 kinds of substituted ureas herbicides in liquid, such as Long, Bromoglossone, Acetylmethrin, Cyclosulfuron, Liguron, Chlorpromethyl, Method.

This standard applies to the determination of the above 15 kinds of substituted ureas herbicides in 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 article Pieces. 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 samples were extracted by acetonitrile, and the extracts were salted out and purified by florisil silica solid phase extraction. After the samples were concentrated, After separation by C18, the sample was decomposed into primary amine by photolysis reactor and reacted with OPA to form a fluorescent substance. After the excitation wavelength was 350 nm, the emission wavelength was measured at 450 nm, and quantified according to the retention time.

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 Acetonitrile (CH3CN).

4.1.2 Methanol (CH3OH).

4.1.3 Acetone (C2H6CO).

4.1.4 n-hexane (C6H14).

4.1.5 isopropanol (C3H8OH).

4.1.6 sodium chloride (NaCl, analytical grade). 140 °C baking 4 h, in the dryer to cool to room temperature, stored in the dryer in reserve.

4.2 Solution preparation

4.2.1 Sodium tetraborate solution (4.0 g/L). Weigh 7.5 g of sodium tetraborate [Na2B4O7 · 10H2O], dissolve in water and dilute to 1 000 mL.

4.2.2 Methanol solution of o-phthalaldehyde (10 g/L). 1.0 g of o-phthalaldehyde [C8H6O2] was weighed and dissolved in methanol and diluted to 100 mL.

4.2.3 mercaptoethanol solution (200 g/L). Weigh 20.0 g of mercaptoethanol [(CH3) 2N (CH2) 2SH · HCl], diluted with sodium tetraborate solution to 100 mL.

4.2.4 Post-column derivatization reagents. Take 5mL of o-phthalaldehyde solution and 5 mL of mercaptoethanol solution, add 500 mL of sodium tetraborate solution in.

4.3 Standards

15 kinds of pesticide standards, purity >= 95%.

4.4 Standard solution preparation

4.4.1 single pesticide standard solution. respectively, accurately weighed pesticide standards, diluted with isopropyl alcohol, one by one dubbed 1 000mg/L single A pesticide standard stock solution, stored below -18 ° C. When used according to the response value of each pesticide, absorb the right amount of standard stock solution, with acetonitrile dilute Release the required standard working solution.

4.4.2 mixed pesticide standard solution. according to the response value of each pesticide, one by one to absorb a certain volume of the pesticide standard stock solution were injected into the same Volumetric flask, diluted with acetonitrile to the scale, prepared into a standard mixed pesticide reserve solution. Diluted with acetonitrile before use to the required standard working solution.

Mix the standard working solution mass concentration see Appendix A.

4.5 Materials

Fryborough Silica Solid Phase Extraction Column. Filler 1000 mg, volume 6 mL.

5 Instruments

5.1 Liquid Chromatography. with fluorescence detector.

5.2 Post-column derivatization with UV photolysis, UV lamp, wavelength 254 nm, 4W; photolysis tube, length 3 m, tube diameter 0.5 mm.

See Appendix B for the connection diagram.

5.3 high speed homogenizer, speed greater than 10 000 r/min.

5.4 nitrogen blowing instrument.

6 Analysis steps

6.1 Preparation of the sample

Sampling samples of vegetable samples according to GB 2763-2014 Appendix A sampling, for the smaller individual samples, after sampling all the treatment;

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. The homogenate was placed in a polyethylene bottle under the conditions of -16 ° C to -20 ° C Save

6.2 Extraction

Weigh 25 g of sample (accurate to 0.01 g) in a 150 mL Erlenmeyer flask, add 50.0 mL of acetonitrile, use a high speed homogenizer 10 000 r/min Homogenized for 2 min and filtered through filter paper. The filtrate was collected in a 100 mL stopper with 5 g to 7 g of sodium chloride. The filtrate was collected from 30 mL to 40 ML, cover the lid, violent shock 1 min, standing for 20 min, so that acetonitrile phase and water phase layer.

6.3 Purification

Absorb the above 10 mL of the upper extract in 20 mL centrifuge tube, slowly blown dry with nitrogen at 50 ° C, add 2.0 mL of n-hexane Solution residue. The Florisil column was pre-eluted with 5 mL of acetone-n-hexane solution (46) and 5 mL of n-hexane, and the solvent the sample solution was immediately added to the surface of the column adsorption layer, the eluate was collected with 15 mL of centrifuge tube, washed with 5 mL of acetone-n-hexane solution (46) Wash the tube with a 20 mL centrifuge tube and repeat it. 15mL centrifuge tube placed in 50 °C water bath, slowly dry with nitrogen, Add 2.5 mL of acetonitrile to dissolve the residue, then add 2.5 mL of water, shaking, over 0.22 µm filter, to be tested.

6.4 Chromatographic reference conditions

Column. C18 column, 5.0 µm, 250 mm ± 4.6 mm, or equivalent.

Column temperature. 25 ° C.

Fluorescence detector. lambdaex350 nm, lambdaem450 nm.

Injection volume. 20 µL.

Flow rate. 0.75 mL/min.

Flow phase gradient. see Table 1.

Post - column derivatization reagent at a flow rate of 0.2 mL/min.

Photolysis temperature. room temperature.

Derived temperature. room temperature.

Table 1 Mobile phase gradient

time

Min

Acetonitrile

0.00 30 70

15.00 50 50

30.00 90 10

32.00 90 10

32.50 30 70

42.00 30 70

6.5 Determination

According to the instrument conditions, the standard working solution and sample solution and other volume of alternate injection, according to the retention time qualitative, external standard method quantitative. Simultaneously Do reagent blank.

7 Results calculated

The amount of pesticide residues measured in the sample is expressed in milligrams per kilogram (mg/kg) in terms of mass fraction, calculated according to the following formula (1).

VAm

VVAc

xxx

Where.

C - the mass concentration of each pesticide in the standard solution, in milligrams per liter (mg/L);

A1 - peak area of each pesticide in the sample;

A2 - peak area of each pesticide in standard solution;

V - sample volume, in milliliters (mL);

V1 - the volume of the sample extract in milliliters (mL);

V2 - the volume of acetonitrile extract in milliliters (mL);

M - sample quality, in grams (g);

The calculated results shall be deducted from the blank values and the calculated results shall be expressed as the arithmetic mean of the two independent determinations obtained under reproducible conditions.

Leaving two effective figures, the content of super 1 mg/kg when the three effective figures.

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 C requirements.

9 Limit of quantification

The limits of this standard method are given in Appendix A.

10 Chromatograms

15 kinds of substituted ureas herbicides standard substance chromatogram shown in Figure 1.

Min7.5 10 12.5 15 17.5 20 22.5 25 27.5 LU 12 ' 1-non-grass; 6-fluorouraone;

2-butyl thiophene; 7-isopropylalon; 12,12'-cyclopyron;

3-methoxone; 8-diuron; 13-4-herbicillin; 9-green valleys; 14-chloropuron;

5-chlorotoluron; 10-bromocuron;

Figure 15 Chromatogram of 15 Substituted Urea Herbicides

Appendix A

(Informative)

15 Chinese and English names of 15 substituted urea herbicides, retention time, detection limit and mixed standard solution concentration

Table A.1 shows the English and Chinese names, retention times, detection limits and mixed standards for 15 substituted urea herbicides analyzed by liquid chromatography

Quasi-solution concentration and other information.

Table A.1 15 Chinese and English names of 15 substituted urea herbicides Pesticides, retention time, mixed standard solution concentration, method limit

Chinese name English name keep time Min Standard solution mass concentration Mg/L Method limit Mg/kg 1 non-grass long fenuron 8.992 0.50 0.03 2 butyl thiophene tebuthiuron 11.093 2.00 0.15

3 Methoxy Long metoxuron 12.429 0.50 0.015 4 mothuron monuron 14.118 0.25 0.015 5 lumplings chlortoluron 17.832 0.50 0.015 6 fluoxeton fluometuron 18.568 0.50 0.015 7 isoproton isoproturon 19.278 0.25 0.015 8 diuron 19.842 0.50 0.015

9 Green Valley Long monolinuron 20.335 0.50 0.03

10 Bromoguron metobromuron 21.678 0.50 0.06

11 Kerosulfuron buturon 23.474 0.50 0.03

Cyclobalanopsis I siduron I 24.022 1.00 0.06 Cyclofton II siduron II 24.581

13 Lee Valley Long linuron 25.319 0.50 0.03

14 Chlorobromonate Chlorobromon 26.038 1.00 0.06

15 Grass less long neburon 29.446 0.50 0.015

NY/T ×× -20 ××

Appendix B

(Informative)

A schematic diagram of the determination of 15 substituted urea herbicides

Figure B.1 Schematic diagram of the determination of 15 substituted urea herbicides

Appendix C

(Normative appendix) Laboratory repeatability requirements

Table C.1 Laboratory repeatability requirements

Measured component content Mg/kg Precision <=0.001 36 > 0.01 > 1 14 Appendix D (Normative appendix) Inter-laboratory reproducibility requirements

Table D.1 Inter-laboratory reproducibility requirements

Measured component content Mg/kg Precision <=0.001 54 > 0.01 > 1 19

......
This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 9 pages — is available in the English PDF.

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