Fluthiacet-methyl

Fluthiacet-methyl is a selective contact herbicide for the post-emergence control of broad-leaved weeds in corn and soybeans. 

The residue definition is for the parent, fluthiacet-methyl, only. 

Fluthiacet-methyl analytical standard material (K-I Chemical Research Institute Co., Ltd)... 

Transfer the concentrate from Section 6.1.1 into a 200-niL separatory funnel with a small amount of water and add 10 mL of saturated sodium chloride solution. Extract three times with 50 mL of n-hexane (a free form of fluthiacet-methyl is present in the aqueous layer see Section 8). Dry the n-hexane extract through 80 g of anhydrous sodium sulfate on a glass funnel and transfer the dried extract into a 300-mL separatory funnel. Extract twice with 70 mL of acetonitrile, collect the extract in a 300-mL round-bottom flask, and evaporate the solvent under reduced pressure. Dissolve the residue in 10 mL of n-hexane-ethyl acetate (4 1, v/v), transfer the solution to a Bond Elut LRC SI column and discard the first eluate. Connect a Sep-Pak Plus NH2 cartridge to the outlet of a Bond Elut LRC SI cartridge and elute fluthiacet-methyl with 15 mL of n-hexane-ethyl acetate (2 3, v/v). Collect the eluate in a 50-mL pear-shaped flask, evaporate the solvent under reduced pressure and dissolve the residue in an appropriate volume of acetone for analysis. 

Dry the dichloromethane extract from Section 6.1.3 with anhydrous sodium sulfate and collect the solution in a 1-L round-bottom flask. Evaporate the solvent at 37 °C under reduced pressure. Dissolve the residue in 4 mL of acetone-n-hexane (1 9, v/v) and adsorb on the top of a silica gel column bed. Rinse the flask three times with 1 mL of the solvent mixture and transfer the rinsings to the column. Elute interfering substances with 85 mL of the solvent mixture and discard the eluate. Then elute fluthiacet-methyl with 140 mL of the solvent mixture. Collect the eluate in a 300-mL... 

The recoveries from untreated control samples fortified with fluthiacet-methyl at 0.2mgkg were 96% [relative standard deviation (RSD) 3.1%] for corn and 74% (RSD 8.0%) for green corn. The limit of detection was 0.01 mg kg 7 The recoveries from untreated control soils fortified with fluthiacet-methyl at 0.1 and 0.2mgkg were 85-103% and 87-103%, respectively. The limit of detection was 0.01 mgkg 7... 

The recovery from water samples fortified with fluthiacet-methyl at 2.0 M-gkg was 92%. The limit of detection was 0.05 ugkg 7... 

The residue R, expressed in milligrams per kilogram of fluthiacet-methyl, is calculated with the following equation ... 

Vi = portion of volume of VEnd injected into the GC or HPLC system ( uL) Wa = amount of fluthiacet-methyl for Vi read from calibration curve (ng)... 

After recovering fluthiacet-methyl from the crop extract with n-hexane, acidify the residual aqueous layer and extract the free form of fluthiacet-methyl with n-hexane-ethyl acetate (2 1, v/v). After evaporating the solvent, clean up the residue with an Ci8 Empore Disk Cartridge. After methylation of the free form with trimethylsilyl-diazomethane, clean up the ester with a Bond Elut LRC SI and a Sep-Pak Plus NH2 cartridge, and quantify as fluthiacet-methyl by GC/FTD. 

After extracting fluthiacet-methyl from the soil extract with n-hexane, pass the residual aqueous layer through a dual cartridge of Sep-Pak Plus NH2 and Sep-Pak Plus C18 to adsorb the free form of fluthiacet-methyl on Sep-Pak Plus Gig. Remove the Sep-Pak Plus C18, wash it with 0.5% acetic acid and acetonitrile-water-acetic acid (20 80 0.5, v/v/v), elute with acetonitrile-water-acetic acid (50 50 0.5, v/v/v) and quantify the free form by HPLC. The operating conditions for HPLC are the same as those for fluthiacet-methyl, except that the mobile phase is acetonitrile-water-acetic acid (50 50 0.5, v/v/v) (retention time 8.8 min). 

Thiadiazole herbicides, e.g., the post-emergence maize-selective herbicide fluthiacet-methyl (119 1999, Action ,... 

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