Determination of residues of homotriazide herbicides and substituted urea herbicides in wheat to prevent some herbicides from causing damage to the next crop during application resulting in yield reduction. Source: Food Safety Monitoring Technology (Chemical Industry Press)
Operation method
Determination of residues of homotriazinyl and substituted urea herbicides in wheat
Materials and Instruments
Wheat Move 1. Extraction 20.0 g (to 0.1 g) of finely ground wheat sample was weighed into a 250 mL centrifuge bottle and 50 mL of 5% acetone-acetonitrile solution was shaken at 20 ℃ for 30 min and centrifuged at 4000 r/min for 15 min, then filtered into a 100 mL volumetric flask, and the residue was washed with 10 mL of extraction solution. The residue was washed with 10 mL of extract solution. Continue to add 30 mL of extract solution to the centrifuge bottle, shaking for another 20 min, centrifuging at 4000 r/ min for 10 min, and then filtering. The filtrate was accepted in the same volumetric flask. The filtrate was washed with another 10 mL of extract. Finally, it was fixed with acetone to the scale. Pipette 25 mL of the sample extract was transferred to a 150 mL milled-mouth cocktail flask and concentrated to dryness on a rotary evaporator at 50 ℃. The concentrated residue was transferred to a 100 mL stoppered measuring cylinder with 3/4 mL acetonitrile in two batches and diluted to 65 mL with water. 2. Purification Insert the HLB solid phase extraction column into the vacuum solid phase extraction device, wash with 6 mL of methanol, then activate with 10 mL of ultrapure water, followed by sampling (65 mL of sample aqueous solution), and then rinsed with 10 mL of 10% methanol-water solution, and discard the effluent. Finally, 1 mL of eluent was used to elute, and the eluent was received in a 5 mL graduated centrifuge tube, and then concentrated with acetonitrile to l mL with shaking, and then passed through an O.45 um organic phase filter membrane, and then detected on the machine. For more product details, please visit Aladdin Scientific website.
Acetone-acetonitrile Acetone Methanol
Centrifugal flasks Volumetric flasks Rotary evaporators Ground-nosed chicken-center flasks Vacuum solid-phase extraction devices
Chromatographic peaks: 1-cycloheximide; 2-glufosinate; 3-pyrazoxystrobin; 4-prochloraz; 5-tricyclazole; 6-thiophene-methachlor; 7-benzthiazole; 8-benzylcarbazole.
Chromatographic column: DB-5MS, 30 m×0.25 mm, O.25 um
Carrier gas: He, 1.O mL/min, constant current
Column temperature: 6O ℃ (l min), rising to 3OO ℃ (15 min) at 10 ℃/min.
Injector temperature: 25O ℃, no shunt injection, empty after 1 min.