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-MS/MS method
Materials and Instruments
Plant Products Soybean Rapeseed Move 1. Extraction Accurately weigh 10.0 g of ground homogeneous sample in a 150 mL plastic centrifuge bottle, add 30 mL of phosphate buffer solution, mix well, adjust the pH to 2 with concentrated hydrochloric acid, add 10 mL of acetone, shake for 20 min, then add 40 mL of anhydrous ether, shake for 20 min, centrifuged at 3500 r/min for 5 min. the upper layer of the solution was transferred to 500 mL split funnel containing 200 mL of distilled water. Transfer the upper solution to a 500 mL separatory funnel containing 200 mL of distilled water, the residue was extracted twice with 10 mL of acetone and 40 mL of anhydrous ether, the upper solution was combined in the separatory funnel, shaken gently for 1 min, and then the ether layer was collected, the aqueous layer was extracted with 25 mL of anhydrous ether, and then the ether layer was combined, and the solution was concentrated under reduced pressure at 30 ℃ under a water bath to about 10 mL. 2. Purification Transfer the sample solution into a 50 mL centrifuge tube, add 15 mL of alkaline aqueous solution, mix thoroughly for 2 min, centrifuged at 1500 r/ min for 10 min, remove the aqueous phase, the ether phase and then 15 mL of alkaline aqueous solution to repeat the extraction of two, combined with the aqueous phase, if the sample contains a high amount of oil and grease (such as soybeans, canola, etc.), add 10 mL of anhydrous ethyl ether in the aqueous phase, mix fully for 2 minutes, at 1500 r/ min centrifuge 10 minutes, the aqueous phase, and the aqueous phase is concentrated to about 10 mL at 30 ℃ under reduced pressure. If the sample contains high oil content (e.g. soybean, rapeseed, etc.), add 10 mL of anhydrous ether to the aqueous phase, mix thoroughly for 2 min, centrifuge at 1500 r/min for 10 min, and discard the ether layer. The aqueous phase was transferred to a 125 mL separatory funnel, carefully adjusted pH<2 with aqueous sulfuric acid, cooled, added 40 mL of anhydrous ether, shaken for 2 min, static layering, collection of ether layer. The aqueous layer was extracted twice with 20 mL of anhydrous ether, and the ether layers were combined. After acidified anhydrous sodium sulfate drying column dehydration, collected in a conical flask containing 108 acidified anhydrous sodium sulfate, shaking from time to time, 2 h after pouring out the ether phase in a water bath at 30 ℃ concentrated under reduced pressure until nearly dry. 3. Derivatization Dissolve the residue with anhydrous ether and transfer to a 4 mL derivatization flask, blow dry under a gentle nitrogen flow at 30 ℃ water bath, add 200 uL of isooctane, 200 uL of methanol, 400 uL of tricresidine diazomethine solution, vortex mixing, and keep it at 70 ℃ for 10 min. cool to room temperature, blow dry under a gentle nitrogen flow, and then condense it with n-hexane to 1 mL, and then pass through a 0.45 pm micropore filter membrane. The filtrate was used for GC-MS determination. The standard working solution was synchronized for derivatization determination. 4. MS parameters: ion trap temperature: 150 ℃; transmission line temperature: 200 ℃; filament current: 80uA; solvent delay: 14.20 min. For more product details, please visit Aladdin Scientific website.
Concentrated hydrochloric acid Phosphate buffer solution Acetone Anhydrous ether Alkaline water Sulfuric acid Nitrogen Methanol Isooctane
Plastic centrifuge bottles Centrifuge tubes Dispensing funnels Conical flasks Derivative flasks