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GB 23200.39-2016: Food safety national standard -- Determination of thiamethoxam and its metabolite thiamethoxam residues in food by liquid chromatography-mass spectrometry / mass spectrometry
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Food safety national standard -- Determination of thiamethoxam and its metabolite thiamethoxam residues in food by liquid chromatography-mass spectrometry / mass spectrometry
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GB 23200.39-2016
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Basic data | Standard ID | GB 23200.39-2016 (GB23200.39-2016) | | Description (Translated English) | Food safety national standard -- Determination of thiamethoxam and its metabolite thiamethoxam residues in food by liquid chromatography-mass spectrometry / mass spectrometry | | Sector / Industry | National Standard | | Classification of Chinese Standard | G25 | | Word Count Estimation | 13,148 | | Date of Issue | 2016-12-18 | | Date of Implementation | 2017-06-18 | | Older Standard (superseded by this standard) | SN/T 3139-2012 | | Regulation (derived from) | State Health Commission, Ministry of Agriculture, Food and Drug Administration Notice No. 16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 23200.39-2016: Food safety national standard -- Determination of thiamethoxam and its metabolite thiamethoxam residues in food by liquid chromatography-mass spectrometry / mass spectrometry
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Food safety national standard - Determination of thiamethoxam and its metabolite thiamethoxam residues in food by liquid chromatography-mass spectrometry/mass spectrometry
ICS
National Standards of People's Republic of China
GB
Replace SN/T 3139-2012
National standards for food safety
Thiamethoxam and its metabolites in the food
Determination
Liquid chromatography - mass spectrometry/mass spectrometry
National food safety standards-
Determination of thiamethoxam and its metabolite clothianidin residues in foods
Liquid chromatography - mass spectrometry
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/T 3139-2012 "Determination of thiamethoxam and its metabolite thiamethoxam residues in export agricultural products. Liquid Chromatography-Mass Spectrometry
/ Mass spectrometry ".
Compared with SN/T 3139-2012, the main changes are as follows.
- Standard text format is modified to national standard text format for food safety;
- the name of the "export of agricultural products" to "food";
- increase the "other food reference implementation" in the standard range.
This standard replaced the previous version of the standard release.
-SN/T 3139-2012.
National standards for food safety
Determination of thiamethoxam and its metabolite thiamethoxam residues in food
Liquid chromatography - mass spectrometry/mass spectrometry
1 Scope
This standard specifies the method of liquid chromatography-mass spectrometry/mass spectrometry for the determination of thiamethoxam and thiamethoxam residues in food.
This standard applies to rice, soybeans, chestnuts, spinach, oil, vegetables, onions, eggplant, potatoes, citrus, mushrooms, tea and other plant sources
Sexual products and chicken liver, pork, milk and other animal-derived products of thiamethoxam, thiophanate residues in the detection and confirmation, other food can refer to the Executive
Row.
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 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 thiamethoxam and thiamethoxam residues in the samples were extracted by 0.1% acetic acid-acetonitrile, and purified by matrix dispersion solid phase extraction.
Determination by liquid chromatography - mass spectrometry/mass spectrometry and external standard method.
4 reagents and materials
Unless otherwise stated, the reagents used are chromatographic grade and the water is in accordance with the primary water specified in GB/T 6682.
4.1 Reagents
4.1.1 Acetonitrile (CH3CN).
4.1.2 Ammonium acetate (CH3COONH4).
4.1.3 acetic acid (CH3COOH). analytical grade.
4.1.4 Formic acid (HCOOH).
4.1.5 Methanol (CH3OH).
4.1.6 n-hexane (C6H14).
4.1.7 anhydrous magnesium sulfate (MgSO4). analytical grade.
4.1.8 anhydrous sodium sulfate (Na2SO4). analytical grade.
4.1.9 N-propyl ethylenediamine (PSA) adsorbent. Particle size 40 μm ~ 60 μm.
4.1.10 Graphite Carbon Black Adsorbent (GCB). Particle size 120 μm ~ 400 μm.
4.1.11 Octadecylsilane (ODS) Bonded Adsorbent (C18). Particle size 40 μm to 60 μm.
4.1.12 matrix dispersion solid phase extractant.
A) for rice, eggplant, onion, potato, citrus sample. 50 mg PSA, 150 mg MgSO4;
B) for spinach, rapeseed sample. 50 mg PSA, 150 mg MgSO4, 10 mg GCB;
C) for chestnuts, mushrooms, milk samples. 50 mg PSA, 150 mg MgSO4, 50 mg C18;
D) for tea, soybean samples. 50 mg PSA, 150 mg MgSO4, 50 mg C18, 10 mg GCB;
E) for chicken liver, pork samples. 50 mg PSA, 150 mg MgSO4, 50 mg C18.
4.2 solution preparation
4.2.1 0.1% acetic acid - acetonitrile solution. take 1 mL of acetic acid, add acetonitrile fixed to 1000 mL, mix.
4.2.2 10 mmol/L ammonium acetate solution (containing 0.1% formic acid). accurately weighed 0.16 g of ammonium acetate in a.200 mL volumetric flask,
A small amount of water dissolved after adding.200 μL formic acid, and then the water volume to the scale, mixing, is now with the distribution.
4.3 standards
4.3.1 thiamethoxam. CAS No. 153719-23-4, molecular formula C8H10ClN5O3S, molecular weight 291.7, pure
Degrees ≥ 99%.
4.3.2 clothianidin. CAS No. 205510-53-8, molecular formula C6H8ClN5O2S, molecular weight 250.2, pure
Degrees ≥ 99%.
4.4 standard solution preparation
4.4.1 thiamethasone standard stock solution. accurately weighed the appropriate amount of thiamethasone standard (accurate to 0.01 mg), dissolved in acetonitrile, preparation
A standard stock solution of 1000 μg/mL was stored at -18 ° C.
4.4.2 Seamethamine standard stock solution. accurately weighed the appropriate amount of thiamethoxamine standard (accurate to 0.01 mg), dissolved in acetonitrile, preparation
A standard stock solution of 1000 μg/mL was stored at -18 ° C.
4.4.3 thiamethoxam and xylidazole mixed standard working solution. according to the need to take appropriate amount of thiamethasone standard solution and the same solution
The solution was diluted with acetonitrile to a standard working solution of 1 μg/mL and stored at -18 ° C.
4.4.4 matrix blank solution. the negative samples of different substrates were treated in accordance with the "extraction and purification" solution obtained after the solution.
4.4.5 matrix standard working fluid. according to the need to absorb the appropriate amount of mixed standard working solution, diluted with a matrix blank solution to the appropriate concentration
Of the standard working fluid, is now available with.
4.5 Materials
4.5.1 Microporous membrane. nylon, 13 mm (id), 0.2 μm.
5 instruments and equipment
5.1 Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometer with Electrospray Ion Source (ESI).
5.2 Crusher.
5.3 Tissue crusher.
5.4 Analytical balance. 0.01 mg and 0.01 g, respectively.
5.5 Ultrasonic Oscillator.
5.6 Vortex Mixer.
5.7 Centrifuge. speed not less than 4 000 r/min.
5.8 Centrifuge tube. with plug, polytetrafluoroethylene, 50 mL.
5.9 Separate funnel. 100 mL, with plug.
6 Preparation and storage of samples
During the operation of the sample preparation, the sample should be prevented from being contaminated or the pesticide residue content will change.
6.1 Preparation of the sample
6.1.1 rice, soybeans, chestnuts, tea leaves
500 g of the sample was taken and pulverized with a pulverizer. Mix, are divided into two as a sample, sub-packaging, sealed, stored at 0 ℃ ~ 4 ℃.
6.1.2 Spinach, Ophiopogon, Onion, Eggplant, Potato, Citrus, Mushroom
A sample of 1000 g was taken, and it was chopped (not washed with water), and then the sample was processed into a slurry by a mashing machine. Mix, both
Divided into two as a sample, sub-packaging, sealed, stored at 0 ℃ ~ 4 ℃.
6.1.3 Chicken liver, pork
500 g of the sample was taken and the mixture was chopped and the sample was processed into a slurry by a mashing machine, and the mixture was divided into two portions as a sample,
Separate, sealed, stored at -18 ° C.
6.1.4 milk
To replace the sample about 500 g, mix, are divided into two as a sample, sub-packaging, sealed, stored at 0 ℃ ~ 4 ℃.
Note. The above sample sampling site according to GB 2763 Appendix A implementation.
7 Analysis steps
7.1 Extraction and purification
7.1.1 rice, soybeans, chestnuts, onions, spinach, rape, eggplant, potatoes, oranges, mushrooms, tea, milk
Weigh 5 g (accurate to 0.01 g) sample in a 50 mL centrifuge tube, add 5 to 8 mL of water to a dry sample, depending on the sample
Set, soak 0.5 h. Add acetic acid - acetonitrile solution so that the total volume of acetonitrile and water 20 mL, homogeneous 0.5min, shake, below 40 ℃ ultrasound
Extraction 30 min, 4000 r/min centrifugation 10min. Take supernatant 1.0 mL, add appropriate amount of matrix dispersed solid phase extractant purification, strong shaking 1min,
4000 r/min for 10 min, the supernatant was filtered through a 0.2 μm filter and analyzed by liquid chromatography-mass spectrometry/mass spectrometry.
7.1.2 Chicken liver, pork
Weigh 5g (accurate to 0.01g) sample in 50 mL centrifuge tube, add about 3g anhydrous sodium sulfate, mix, add 10 mL of acetic acid - B
Nitrile solution, 10 mL n-hexane, homogenized 3 min, 4000 r/min centrifugal 10 min, transfer the extract to the separatory funnel, shake well after standing
The layers were collected and the acetonitrile layer was collected. Repeat the extraction again by the same operation. The n-hexane layer was washed with 10 mL of acetonitrile, and the mixture was allowed to stand and collected
Nitrile layer. The three layers of the acetonitrile layer were combined and sintered at 40 ° C to near dryness. The mixture was fixed to 20 mL with acetic acid-acetonitrile solution and 1.0 mL
The amount of matrix dispersed solid phase extraction agent purification, strong shaking 1min, 4000 r/min centrifugal 10min, take the supernatant with 0.2 μm filter,
Determination by liquid chromatography-mass spectrometry/mass spectrometry.
7.2 Determination
7.2.1 Liquid Chromatographic Reference Conditions
A) Liquid chromatography column. ACQUITY UPLC BEH C18, 50 mm × 2.1 mm (id), particle size 1.7 μm, or equivalent.
B) Column temperature. 35 ° C.
C) mobile phase gradient. see Table 1.
Table 1 Mobile phase elution gradient table
Time (min)
Flow rate
(ML/min)
10 mmol/L Ammonium acetate solution (4.10) (%) Methanol (%) Curve type
1 Initial 0.25 90.0 10.0
2 0.50 0.25 90.0 10.0 1
3 2.50 0.25 50.0 50.0 6
4 3.00 0.25 90.0 10.0 1
D) Injection volume. 2.0 μL.
E) Sample chamber temperature. 10 ° C.
7.2.2 Mass spectrometry reference conditions
See Appendix A.
7.2.3 Preparation of standard curve
A blank solution of the substrate was prepared by a pretreatment step in a blank sample of 5.0 g, the standard intermediate solution was diluted to 2.0, 5.0, 10.0,
40.0,100.0 ng/mL, but the origin to do the standard working standard matrix should be used with the current distribution.
7.2.4 Quantitative determination
The method is quantitatively determined by external standard calibration curve method. To reduce the effect of matrix on the quantitative determination, the quantitative standard curve should be used
Quality standard working solution drawn by the standard working curve, and to ensure that the measured sample of pesticide response values are within the linear range. above
The retention times of thiamethoxam and thiamethoxam were about 2.51 min and 2.92 min, respectively. The multi-reactive ion monitoring chromatogram
Record B in Figure B.1.
7.2.5 Qualitative determination
Under the above conditions, the retention time of the test substance in the test solution should be within the time window of the standard solution retention time,
The relative abundance should be consistent with the relative abundance of the standard, and the error does not exceed the range specified in Table 2. Thiamethoxam and thiamethasone standards
The ion monitoring chromatogram is shown in Appendix B, Figure B.1.
Table 2 Qualitative determination of relative ion abundance maximum allowable deviation
Relative abundance (base) 50% 20% to 50% 10% to 20% ≤10%
Allowable relative deviation ± 20% ± 25% ± 30% ± 50%
7.3 blank test
In addition to no sample, according to the above steps.
8 results are calculated and expressed
Determination of thiamethoxazole or thiophanate pesticide residues in the samples by liquid chromatography-mass spectrometry/mass spectrometry using standard curve method, standard curve method
Quantitative results calculated by formula (1).
Xi ci
(1)
Where.
Xi - Residue of thiamethoxazole or chlortetracycline pesticide in milligrams per kilogram (mg/kg);
Ci - the concentration of the solution to be measured from the standard curve, in micrograms per milliliter (μg/mL);
V - the total volume of the sample extract in milliliters (mL) (20.0 mL in this method);
M - the mass of the sample represented by the final sample solution in grams (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 reproducible conditions and their arithmetic mean (percentage) shall be in accordance with the
Record the requirements of D.
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 the
Record the requirements of E.
10% limit and recovery rate
10.1 Quantitation limits
The lower limit of determination of thiamethoxam and xylidazole was 0.010 mg/kg.
10.2 Recovery rate
The range of addition and recovery of this method is given in Appendix C.
Appendix A
(Informative)
Thiamethoxam and doxorubicin
Thiamethoxam and thiamethoxam analysis conditions.
A) Ionization mode. ESI;
B) Detection method. MRM;
C) Capillary voltage. 3.00 kV;
D) nitrogen blowing flow. 800 L/h;
E) Taper hole air flow. 50 L/h;
F) Solvent gas temperature. 350 ° C;
G) Amplifier voltage. 650 V;
H) ion source temperature. 110 ° C;
I) monitoring of ions, collision energy and cone hole voltage (see Table A.1).
Table A.1 Monitoring parameters of thiamethoxam and doxorubicin for multiple reaction ions
Component
Monitor ion pairs
(Channel Reaction) (m/z)
Dwell time
(Dwell) (s)
Cone hole voltage (Cone)
(V)
Collision energy
(Collision Energy) (V)
Thiamethoxam
* 292/211 0.050 20.0 19.0
292/181 0.050 20.0 10.0
Thiamethoxazole
* 250/169 0.050 16.0 15.0
250/131 0.050 16.0 10.0
* For quantitative ion pairs
The above listed parameters were completed at the Waters AcquityTM UPLC-Quattro Premier mass spectrometer, which lists the test instrument models only for reference,
Does not involve commercial purposes, encourage standard users to try to use different manufacturers or models of equipment.
Appendix B
(Informative)
Thiamethoxam and xylidazole standard solution
Figure B.1 Multi-reaction monitoring (MRM) chromatogram of LC-MS/MS for thiamethoxam/thiamethasone standard solution (concentration of 10 ng/mL)
Appendix C
(Informative)
Thiamethoxazole, thiophanate recovery range
Table C.1 Concentration and recovery range of thiamethoxam and xylidazole in different matrix samples (%) (n = 10)
Sample Concentration (mg/kg) Thiamethoxazole Recovery Range (%) Seamethoxide Recovery Range (%)
Rice
0.010 72.4 ~ 79.6 84.4 ~ 106.4
0.020 88.2 ~ 103.6 92.2 ~ 106.6
0.040 92.3 ~ 102.1 92.4 ~ 108.7
Soybeans
0.010 73.2 ~ 93.6 76.8 ~ 94
0.020 71.6 ~ 76.2 79.2 ~ 93.2
0.050 70 ~ 78.1 90.16 ~ 102.8
0.10 87.2 ~ 105.8 87.8 ~ 100.6
chestnut
0.010 82.0 ~ 99.2 74.0 ~ 94.4
0.020 83.2 ~ 98.2 83.2 ~ 95.8
0.040 88.5 to 95.5 85.9 to 95.1
spinach
0.010 104.4 ~ 109.2 84.4 ~ 97.2
0.020 94.4 ~ 109.6 90.4 ~ 107.2
0.040 84.7 ~ 108.7 72.6 ~ 89.3
2.0 91.4 ~ 95.5 78.2 ~ 89.7
Yogurt
0.010 74.8 ~ 101.2 73.6 ~ 99.6
0.020 78.2 ~ 99.0 75.2 ~ 100.2
0.040 86.1 to 99.1 80.6 to 104.2
eggplant
0.010 90 ~ 102.4 72.8 ~ 97.2
0.50 99.3 to 108.4 94.7 to 104.9
1.0 100.3 ~ 105 98.5 ~ 107.8
onion
0.010 96.8 ~ 109.6 82.4 ~ 100.8
0.020 98.0 ~ 110.0 86.2 ~ 103.2
0.040 101.1 ~ 109.3 84.0 ~ 91.0
potato
0.010 75.2 ~ 98.8 92.0 ~ 100.0
0.25 72.5 to 84.0 91.1 to 100.2
0.50 70.6 ~ 89.0 71.8 ~ 87.7
Sample Concentration (mg/kg) Thiamethoxazole Recovery Range (%) Seamethoxide Recovery Range (%)
mushroom
0.010 73.6 ~ 99.2 87.6 ~ 106.0
0.020 102.8 ~ 107.4 100.6 ~ 109.4
0.040 103.0 to 112.8 101.1 to 109.8
Tangerine
0.010 75.6 ~ 85.2 84.0 ~ 95.6
0.040 93.0 ~ 105.5 94.9 ~ 107.1
0.50 89.6 ~ 108.0 96.4 ~ 112.4
1.0 97.6 ~ 104.4 98.2 ~ 101.8
0.010 71.6 ~ 95.2 83.6 ~ 101.6
0.050 82.6 ~ 91.1 90.7 ~ 101.4
0.10 80.9 to 88.1 95.0 to 100.7
20 (thiamethoxam)/50 (thiamethoxamate) 79.2 ~ 97.2 80.3 ~ 95.5
Chicken liver
0.010 78.0 ~ 93.2 88.8 ~ 107.6
0.020 80.4 ~ 96.6 83.4 ~ 96.8
0.040 79.6 ~ 97.0 74.1 ~ 93.3
pork
0.010 70.8 ~ 86.4 80.8 ~ 98.4
0.020 70.2 ~ 84.6 73.4 ~ 91.8
0.040 82.1 to 92.7 80.5 to 90.4
milk
0.010 83.2 ~ 92.8 94.4 ~ 109.2
0.020 76.2 ~ 86.8 92.6 ~ 103.8
0.040 95.0 ~ 105.3 97.6 ~ 108.8
Note. Due to the high MRL values of some samples, to ensure accurate quantitative results and to avoid contamination of the instrument, a higher level of added concentration
In the machine before the following dilution.
A. add the level of.2000μg/kg, diluted 10 times after the machine test;
B. add the level of 1000μg/kg, diluted 10 times after the machine detection;
C. Add the level of 500μg/kg, diluted 5 times after the machine test;
D. add the level of 20mg/kg (thiamethoxam), 50mg/kg (thiamethoxazole), diluted.200 times after the machine test.
Appendix D
(Normative appendix)
Laboratory repeatability requirements
Table D.1 Laboratory repeatability requirements
Measured component content
Mg/kg
Precision
0.001 36
> 0.01
> 1 14
Appendix E
(Normative appendix)
Inter-laboratory reproducibility requirements
Table E.1 Inter-laboratory reproducibility requirements
Measured component content
Mg/kg
Precision
0.001 54
> 0.01
> 1 19
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