Determination of amide herbicide residues in cereals and oilseeds

Summary

Some herbicides can cause damage to the next crop during application resulting in reduced yields, so residues in agricultural fields have also attracted the attention of agricultural chemists. Source: Food Safety Monitoring Technology (Chemical Industry Press)

Operation method

GC-ECD method

Materials and Instruments

Grain Oilseeds
Acetone Hexane Ether Sodium Chloride Sodium Sulfate Anhydrous Acetonitrile
Aubergine vials Gel chromatography columns Florisil solid-phase extraction columns Centrifuge tubes Batch tubes

Move

1. Extraction Weigh about 10 g (accurate to 0.01 g) of the sample in a 50 mL centrifuge tube, add lO mL of water, soak overnight; add 20 mL of acetone, shaking for 3 min, centrifuged at 4,000 r / min for 4 min, the extraction solution was transferred to 250 mL eggplant shaped bottles, and the residue in the centrifuge tube and then extracted the residue with 2 × 30 mL of acetone, and then added to the eggplant shaped bottles, and then evaporated at 38 ℃, under reduced pressure. Removal of acetone: the residue (about 10 mL) was transferred to another 50 mL centrifuge tube. Wash the aubergine bottle with 10 mL of 10% sodium chloride solution and 15 mL of hexane, and transfer the washing solution into the centrifuge tube, shake the extraction for 3 min, centrifuge at 2500 r/min for 3 min, collect the n-hexane phase, and then extract the extract with 30 mL×2 hexane, and then combine with the n-hexane phase. 2. Liquid-liquid partition purification The hexane phase was dehydrated by adding anhydrous sodium sulfate, and the hexane was completely transferred to another 250 mL aubergine flask and evaporated to dryness under reduced pressure. The residue was dissolved with 2×5 mL of hexane and transferred to a 50 mL centrifuge tube, 3×10 mL of acetonitrile saturated with hexane was added for extraction, the acetonitrile phase was transferred to another 50 mL centrifuge tube, 10 mL of acetonitrile saturated with hexane was added for extraction, the hexane phase was discarded, the acetonitrile phase was transferred to a 100 mL aubergine flask, and evaporated to dryness under reduced pressure, and the residue was dissolved with 5 mL of hexane. 3. Purification by solid phase extraction The above hexane phase was transferred into a Florisil solid phase extraction column (125 mg, 3 mL), the flow rate of the liquid through the column was kept at 0.5 drops per second, then the aubergine bottle was washed with 15 mL of n-hexane-ether mixture (85 + 15) and transferred into the column, all the eluent was collected in a dosing tube, blown nitrogen and concentrated to near dryness, the residue was dissolved by addition of n-hexane and was concentrated to 1.0 mL, and then analyzed for GC-ECD. Analyzed by GC-ECD.

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