GB 23200.83-2016Food safety national standard -- Detection Method of Net Residue of Different Rice Blast in Food (English PDF)

4.1 Reagents

4.1.1 N-Hexane (C6H14). Distillation.

4.1.2 Acetone (CH3COCH3). Distillation.

4.1.3 Sodium chloride (NaCl).

4.1.4 anhydrous sodium sulfate (Na2SO4). 650 ° C burning 4 h, set the dryer in the spare.

4.2 Solution preparation

4.2.1 Acetone + n-Hexane (1 2) Solution. Take 100 mL of acetone, add.200 mL of n-hexane and shake well.

4.2.2 acetone + n-hexane (1 1) solution. take 100 mL of acetone, add 100 mL of n-hexane, shake back.

4.3 Standards

4.3.1 Substituted rice blast standard substance (Iprobenfos, C13H21O3PS, CAS. 26087-47-8). purity > 99%.

4.4 Standard solution preparation

4.4.1 standard reserve solution. accurately weighed the appropriate amount of different rice blast net standard material, with acetone will be formulated into 1000 µg/mL standard reserve Liquid, and then according to the test requirements with n-hexane diluted to the corresponding standard working solution. The standard solution is protected from light at 4°C.

4.5 Materials

4.5.1 Graphitized carbon black solid phase extraction column. 3 mL, 125 mg, or equivalent.

4.5.2 Neutral Alumina Solid Phase Extraction Column. 3 mL, 125 mg, or equivalent.

6.1 Preparation of the sample

6.1.1 Fruits or vegetables

Take a representative sample 500 g, chopped water can not be washed, with a crusher to sample processed into a slurry. Mix well and put it clean of the container, sealed and marked.

6.1.2 Tea and grain

Take a representative sample of 500 g, crushed with a pulverizer and passed through a 2.0 mm round hole sieve. Mix well, into a clean sample container, Sealed and marked.

6.1.3 Meat and meat products

Take a representative sample of 500 g, cut it, and use a crusher to process the sample into a slurry, mix it, and mix it into a clean sample Inside, sealed and marked.

Note. The above sample sampling site according to GB 2763 Appendix A implementation.

6.2 Sample storage

Tea, bee products, condiments and cereals and other samples stored at 0 4 ° C; fruits and vegetables and meat and meat products such as samples in -Frozen below 18°C.

During the operation of the sample preparation, the sample should be protected from contamination or changes in the content of the residue.

7.1 Extraction

For tea, chestnut, honey, rice samples, weighed 1 g homogeneous sample (accurate to 0.001 g), for spinach, buckwheat head, Apple, vinegar, chicken, beef, fish samples, weighed 2 g homogeneous sample (accurate to 0.001 g). Place the weighed sample at 15 mL Centrifuge tube, add 1 g of sodium chloride, add 2 mL of distilled water, mix on the mixer for 30 s, placed 15 min. Add 3 mL to C Ketone + n-hexane mixture, and mixed on a mixer for 2 min. 2500 r/min centrifugation 1 min, drawing the upper n-hexane extract in another A test tube. And then add 3 mL of acetone + n-hexane mixture to extract twice, the combined extract.

7.2 Purification

7.2.1 Tea, spinach, buckwheat head, apple, chestnut, honey sample

A graphitized carbon black solid phase extraction column (1 cm high anhydrous sodium sulfate layer in the column) was installed in a solid phase extraction vacuum suction apparatus , First with 1 mL³3 acetone pre-elution extraction column, and then 1 mL³³ n-hexane pre-elution extraction column, discard all pre-eluent. will the n-hexane extract was added to the graphitized carbon black solid phase extraction column and the extract was completely eluted and then mixed with 3 mL of acetone + n-hexane the column was eluted and the flow rate was maintained at 1.5 mL/min. The whole effluent was collected and the nitrogen stream was blown to near dry at 45 ° C. Finally with positive Hexane volume to 0.5 mL for GC-MS analysis.

7.2.2 Vinegar, rice, chicken, beef, fish samples

A neutral alumina solid phase extraction column (1 cm high anhydrous sodium sulfate layer in the column) was installed in a solid phase extraction vacuum suction apparatus on the first, with 3 mL of acetone pre-elution extraction column, and then 3 mL n-hexane pre-elution extraction column, discard all pre-leaching solution. A mixture of n-hexane the extract was added to a neutral alumina solid phase extraction column, and the extract was completely eluted and then eluted with 3 mL of an acetone + n-hexane mixture the column was collected and the flow rate was maintained at 1.5 mL/min. The whole effluent was collected and the nitrogen stream was blown to near dry at 45 ° C. Finally, with n-hexane capacity to 0.5 mL for GC-MS analysis.

7.3 Determination

7.3.1 Gas Chromatography - Mass Spectrometry Reference Conditions

A) Column. HP-5MS quartz capillary column, 30 mx 0.25 mm (id), film thickness 0.25 m, or equivalent;

B) Column temperature. Initial temperature 80 °C, rise to 205 °C at 7 °C/min and up to 280 °C at 25 °C/min 5 min;

C) Inlet temperature. 280 °C;

D) Chromatography-Mass Spectrometer Interface Temperature. 270 °C;

E) Carrier gas. helium, purity greater than or equal to 99.995%, 0.8 mL/min;

F) Injection volume. 1 µL;

G) Injection method. no split injection, 1 min after the valve;

H) ionization mode. EI;

I) ionization energy. 70 eV;

J) Detection method. Select the ion monitoring mode (SIM);

K) monitoring ions (m/z). 203, 204, 246, 288; quantitative ions. 204;

L) solvent delay. 10 min.

7.3.2 Determination and confirmation of chromatography

According to the content of different rice blast in the sample solution, the standard working solution with similar peak area is selected, and the standard working fluid and sample solution the response value of the rice in the standard working solution and the sample solution should be within the linear range of the instrument detection.

Under the same experimental conditions, the mass retention time of the material to be tested in the sample was the same as that of the standard working solution, After the sample quality chromatography, the selected ions are present, after comparing the abundance of the selected ions with the standard corresponding to the abundance of ions, its value within the allowable range (allowable range in Table 1) can determine the existence of the corresponding sample in the sample. In the "7.3.1" provisions of this method Under the condition of chromatography, the reference retention time of the rice blast is 17.70 min, and the monitoring ion (m/z) abundance ratio is 203.204.246.288 = 17. 100. 15. 19. See Appendix A for chromatograms and spectra.

Table 1 Maximum qualitative error of relative ion abundance when qualitative gas chromatography-mass spectrometry

Relative abundance (base) 50% 20% to 50% 10% to 20% <=10% Allowable relative deviation ± 20% ± 25% ± 30% ± 50%

7.4 Blank experiment

In addition to the sample, according to the above determination steps.

10.1 Quantitation limits

The limit of the net limit of rice blast is 0.005 mg/kg.

10.2 Recovery rate

When the levels were 0.005 mg/kg, 0.01 mg/kg, 0.02 mg/kg, the added recoveries of the different rice blast were given in Appendix B.

Appendix A

(Informative)

Total Ion Flow Chromatogram and Mass Spectrometry of Purified Raw Material of 1 0. 01 01 .0 01 2 .0 01 3 .0 01 4 .0 01 5 .0 01 6 .0 01 7 .0 01 8 .0 01 9 .0 02 .0 02 1 .0 02 2. 0 02 3 .0 02 4 .0 0 T ime - - > A bundance (2 0 3 .7 0 to 2 0 4 .7 0). STD 0 9 0 5 D .D 1 7 .7 0

Figure A.1 Total ion chromatogram of the target substance of different rice blast

6 0 8 0 1 0 01 2 01 4 01 6 01 8 02 0 02 2 02 4 02 6 02 8 0 M/z - - > A bundance 0.20 97.5 119.0 tea 0.005 74.9 93.3 0.01 90.8 107.9 0.02 83.5 108.1 spinach 0.005 86.8110.1 0.01 91.9 110.5 0.02 107.1 118.9 apple 0.005 75.386.5 0.01 92.8 119.9 0.02 95.6 113.1 honey 0.005 96.8 114.4 0.01 97.7 115.5 0.02 91.2 112.8 Chestnut 0.005 109.9 120.9 0.01 90.2 108.8 0.02 88.8 119.5 Vinegar 0.005 93.4 104.2 0.01 89.9 100.6 0.02 95.2 107.2 Buckwheat head 0.005 87.698.5 0.01 93.7 100.6 0.02 82.1 94.3 Fish 0.005 81.8104.9 0.01 80.9 94.0 0.02 90.0 106.8 beef 0.005 86.499.4 0.01 92.4 111.0 0.02 94.2 111.9 chicken 0.005 70.9103.0 0.01 70.2 93.1 0.02 73.392.7 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 Second, gas chromatography

14.1 Reagent

14.1.1 n-hexane (C6H14). re-distillation.

14.1.2 Acetone (CH3COCH3). Distillation.

14.1.3 anhydrous sodium sulfate (Na2SO4). 650 ° C burning 4 h, set the dryer in the spare.

14.2 Solution preparation

14.2.1 acetone n-hexane (1 2) solution. take 100 mL of acetone, add.200 mL of n-hexane, shake back.

14.2.2 standard reserve solution. accurately weighed the appropriate amount of different rice blast net standard material, with acetone will be formulated into 1000 µg/mL standard reserve Liquid, and then according to the test requirements with n-hexane diluted to the corresponding standard working solution. The standard solution is protected from light at 4 °C.

14.3 Standards

14.3.1 Substituted rice blast standard substance (Iprobenfos, C13H21O3PS, CAS. 26087-47-8). purity > 99%.

14.4 Materials

14.4.1 Graphitized Carbon Black Solid Phase Extraction Column. 3 mL, 125 mg, or equivalent.

14.4.2 Neutral Alumina Solid Phase Extraction Column. 3 mL, 125 mg, or equivalent.

16.1 Sample preparation

16.1.1 Fruits or vegetables

Take a representative sample 500 g, chopped water can not be washed, with a crusher to sample processed into a slurry. Mix well and put it clean of the container, sealed and marked.

16.1.2 Tea and Grains

Take a representative sample of 500 g, crushed with a pulverizer and passed through a 2.0 mm round hole sieve. Mix well, into a clean sample container, Sealed and marked.

16.1.3 Meat and meat products

After picking 500 g of the sample, it was chopped and the sample was processed into a slurry by a crusher and mixed into a clean sample container Inside, sealed and marked.

Note. The above sample sampling site according to GB 2763 Appendix A implementation.

16.2 Sample storage

Tea, bee products, condiments and cereals and other samples stored at 0 4 °C; fruits and vegetables and meat and meat products such as samples in -Frozen below 18°C.

During the operation of the sample preparation, the sample should be protected from contamination or changes in the content of the residue.

17.1 Extraction and purification

17.1.1 For rice, chestnut, honey samples Weigh 2 g (accurate to 0.001 g) homogeneous sample in a 10 mL centrifuge tube, add 2 mL of water, add anhydrous sodium sulfate of the saturated, add 2 mL of acetone + n-hexane mixture to extract twice, each 2 min, and then centrifuged 3 min (centrifugal speed 2 000 r/min), the upper layer of the extract was taken on the graduated centrifuge tube; the residue was extracted twice with 2 mL of n-hexane and the combined extracts were Centrifuge tube, in a multi-functional micro-sample processor or other equivalent equipment, at 40 °C with nitrogen flow to 1.0 mL, for Injection analysis.

17.1.2 For spinach, apples, vinegar samples Weigh 2 g (accurate to 0.001 g) homogeneous sample in a 10 mL centrifuge tube. For tea samples, weigh 0.5 g (exact to 0.001 g) homogeneous sample in a 10 mL centrifuge tube, add 2 mL of water, add anhydrous sodium sulfate to make it saturated with 2 mL of acetone + the mixture was extracted twice for 2 min each time and then centrifuged for 3 min (centrifugation at 2 000 r/min).

Take the solution in another centrifuge tube. Residue and then 2 mL of n-hexane extraction twice, combined with the upper extract, to be purified. In graphitized carbon black the solid phase extraction column was charged with 1 cm high anhydrous sodium sulfate at the top of the solid phase extraction column. The solid phase extraction column was pre-eluted with 4 mL of acetone + n-hexane mixture to the whole pre-eluent, and then the above extract into the solid phase extraction column, all the extract to the solid phase extraction column, and then 4 mL Acetone + n-hexane mixture to collect all the effluent in a graduated centrifuge tube, and finally in the multi-functional micro-sample processor or its He was on a comparable instrument and was blown to 1.0 mL at 40 ° C with a nitrogen stream for sample analysis.

17.1.3 For beef, chicken, fish samples Weigh 2 g (accurate to 0.001 g) homogeneous sample in 10 mL centrifuge tube, add anhydrous sodium sulfate to make it saturated, with 6 mL Acetone + n-hexane mixture was extracted once for 2 min, then centrifuged for 3 min (centrifugation speed of 2 000 r/min) Set the upper extract in another tube. Residue and then 2 mL of n-hexane extraction twice, combined with the upper extract, to be purified. In neutral oxygen the solid phase extraction column was packed with 1 cm high anhydrous sodium sulfate at the top of the aluminum solid phase extraction column. The solid phase extraction column was pre-leached with 4 mL of acetone + n-Discard all the pre-leaching solution, and then the extract into the solid phase extraction column, all the extract to the solid phase extraction column, and then 4 mL of acetone + n-hexane mixture to collect all the effluent in the graduated centrifuge tube, and finally in the multi-functional micro-sample processor or other equivalent instruments, at 40 ° C with a nitrogen stream to 1.0 mL for sample analysis.

17.2 Determination

17.2.1 Chromatographic reference conditions

A) Column. EQUITYTM ~ 1701 capillary column, 30 m³0.32 mm (Id) ³1.0 µm or equivalent;

B) Heating procedure. Initial temperature 100 °C, rise to 220 °C at 10 °C/min for 10 min;

C) Inlet temperature. 250 ° C;

D) Detector temperature. 250 ° C;

E) Carrier gas. nitrogen, purity greater than or equal to 99.99%, flow rate 5.0 mL/min;

F) Hydrogen. 75 mL/min;

G) air. 100 mL/min;

H) tail gas. 20 mL/min;

I) Injection method. no split injection, 1.0 min after opening the valve;

J) Injection volume. 2 µL.

17.2.2 Chromatographic determination

According to the sample of different rice blast net content, selected with the sample concentration similar to the standard working solution. The standard working solution of different rice blast and the net value of different rice blast in the sample solution should be within the linear range of the instrument. Standard working solution and sample solution and other volume interspersed injection determination, with the retention time qualitative, the measured peak area is quantified with the standard working fluid. Under the above chromatographic conditions, the difference is the net standard substance the chromatogram is shown in Appendix B, Figure B.1.

17.3 Blank test

In addition to the sample, according to the above determination steps.

Calculation and presentation of results Use the chromatographic data processor or calculate the residual amount of isoflavones in the sample according to the following formula (1). The calculation result is deducted from the blank value.

A³C³V

AS³m

Where.

X - sample of different rice blast net content, mg per kilogram, mg/kg;

A - the peak area of the different rice blast in the sample solution;

AS - standard peak area of isoflavones in standard working solution;

C - standard working solution in different concentrations of rice blast, micrograms per milliliter, µg/mL;

V - sample solution final volume, ml, mL;

M - the quality of the sample to be weighed, g, 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.

20.1 Quantification limit

The limit of quantification in rice, spinach, apple, beef, chicken, fish, honey and chestnut is 0.005 mg/kg.

The limit of quantification in tea is 0.01 mg/kg.

20.2 Recovery

When the levels were 0.005 mg/kg, 0.01 mg/kg, 0.2 mg/kg, the added recoveries of the different rice blast were given in Appendix F.

Appendix E

(Informative)

Chromatogram of net standard substance of different rice blast

Figure E.1 Chromatogram of net standard substance of rice blast

Appendix F

(Informative)

Sample concentration and recovery of the experimental data

Table F.1 Experimental data on the concentration and recovery of the sample

Sample name Add concentration (mg/kg) Recovery rate range (%) Rice 0.005 75.094.0 0.01 81.0 106 0.2 88.092.5 spinach 0.005 92.2 102 0.01 82.3 108 0.02 82.098.5 apple 0.005 74.8 91.2 0.01 78.5 98.1 0.02 80.5 105 beef 0.005 93.8 106 0.01 86.5 104 0.02 87.5112 chicken 0.005 84.0101 0.01 85.0 102 0.02 81.0103 Fish 0.005 94.6 100 0.01 86.0117 0.02 86.0108 honey 0.005 82.6 91.6 0.01 86.6 105 0.02 77.0 92.0 Chestnut 0.005 72.6 88.8 0.01 72.5 88.8 0.02 78.5 85.5 tea 0.005 80.2107 0.01 84.0 106 0.02 86.8 107 Vinegar 0.005 93.6 100 0.01 89.5 105 0.02 94.5 102 Appendix G (Normative appendix) Laboratory repeatability requirements

Table G.1 Laboratory reproducibility requirements

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

Table H.1 Inter-laboratory reproducibility requirements

Measured component content Mg/kg RSD <=0.001 54 > 0.01