Pesticide residue solid phase extraction method in cereals, beans, nuts and seeds

Pesticide residue solid phase extraction method in cereals, beans, nuts and seeds
Sample preparation
a. Weigh 10g sample, add 20mL water, and place for 1 min;
b. Add 50mL acetonitrile, homogenize, suction filtration, rinse the residue on the filter paper with 20mL acetonitrile, combine the filtrate, and dilute to 100mL with acetonitrile;
c. Measure 20 mL of the filtrate, add 10 g of NaCl and 20 mL of 0.5 mol/L phosphate buffer (pH 7.0), shake well for 10 min, let stand for stratification, and discard the aqueous layer;
2. C18 SPE purification
a. Activation: Bond Elut C18 (1 g) column, rinsed with 10 mL of acetonitrile for activation;
b. Load: Add 20 mL of extract. Collecting the effluent solution;
c. Elution: elute with 2 mL of acetonitrile, receive the eluent, and combine all the effluent solutions;
d. Dehydration: The collected solution is passed through a funnel containing anhydrous sodium sulfate, and the funnel is rinsed with an appropriate amount of acetonitrile to collect the entire filtrate;
e. Concentration: At a temperature below 40 ° C, concentrate near-dry and re-dissolve with 2 mL of acetonitrile / toluene (3:1) for further purification.
3. Carbon/NH2 SPE purification
a. Activation: Bond Elut Carbon/NH2 (500 mg/500 mg) column, rinsed with 10 mL acetonitrile/toluene (3:1) for activation;
b. Loading: 2 mL of the preliminary purified sample solution in the previous step is added to the Carbon/NH2 SPE column;
c. Elution: Rinse the SPE column with 20 mL of acetonitrile/toluene (3:1) and collect all the loading effluent and eluent;
d. Concentration: below 40 ° C, concentrated near dry, then add 5mL of acetone to redissolve and concentrate near dry, dissolved in acetone / n-hexane (1:1), to a volume of 1mL.
4. GC-MS or GC-MS/MS detection
5. The sample contains hundreds of insecticides, fungicides, herbicides, feed additives, veterinary drugs, etc.
SPE column used in this method:
Bond Elut C18 (1g, 6mL, PN.12256001)
Bond Elut Carbon/NH2 (500 mg/500 mg, 6 mL, PN. 12252202).
The method satisfies the simultaneous detection requirements of residual pollutants in hundreds of foods such as insecticides, fungicides, herbicides, feed additives and veterinary drugs in the Japanese Pesticide Residue Regulations.

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