Extraction procedure Sample Clauses

Extraction procedure. Extraction was performed with the liquid-liquid extraction methodology and 100mL of the sample was measured with a graduated cylinder and extracted with 20mL of dichloromethane (DCM) in a separatory funnel. The mixture was shaken for 2 minutes and allowed to separate for 5 minutes. The bottom layer was decanted into a pre-cleaned and labeled flask and wrapped in foil. This step was repeated twice per sample (60 mL DCM total) and all samples were stored in the refrigerator until GC-FID analysis. The separatory funnels were cleaned between sample extractions with a detergent and tap water rinse followed by deionized water rinse. The funnel was then rinsed with acetone and again with dichloromethane. A clean-up step was deemed unnecessary since the samples were well and borehole water that were not notably contaminated with other particulate matter.

Extraction procedure. Fillion, et al., used an acetonitrile extraction with a first cleanup with a C18 cartridge followed by an additional cleanup with carbon SPE cartridge coupled to an aminopropyl cartridge cleanup to remove co-extractives. Determination of pesticides was by GC with mass-selective detection in the selected-ion monitoring mode and liquid chromatography with post-column reaction and fluorescence detection for N- methyl carbamates (Fillion, et al. 2000). We used a 1 g sample versus the 50 g sample used by Fillion and co-workers, thus our method required less solvent (30 mL vs. 105 mL) and a smaller sample size. We modified the QuEChERS and Fillion methods (22,