Pesticide Analytical Manual Vol. I SECTION 401 C1 LIQUID-LIQUID PARTITIONING AND CHARCOAL/CELITE COLUMN CLEANUP Reference Krause, RT(1980)/. Assoc Of. Anal. Chem. 63, 1114-1124 Principles Residues in aqueous extract are transferred to acetonitrile by liquid-liquid partition- ing in the presence of sodium chloride. Co-extractives are removed from the acetonitrile solution by partitioning them into petroleum ether, which is discarded Residues are partitioned from acetonitrile into methylene chloride. Methylene chloride solution is cleaned up on a charcoal/Celite column, and residues are eluted with toluene/acetonitrile Apparatus chromatographic column, 22 mm id x 300 mm, Teflon stopcock,coarse porosity fritted dise chromatographic column, 25 mm id, plain evaporator, vacuum rotary, as described in E-1 flasks, round-bottom(r-b), 250 and 500 mL, 1 L, T24/40 magnetic stirrer, star, 10 mm diameter x 8 mm height separatory funnel (separator), 250 and 500 mL vacuum adapter, side arm, with 324/40 joints agent acetonitrile, distilled from all-glass apparatus; see Section 204 for distillation Celite 545 harcoal(Nuchar S-N), produced by Westvaco Corp. and available from Eastman Kodak. Cat. No. 118 0454 1+4(w/w) charcoal/Celite, combined after each is prepared as directed below; mix thoroughly and store in sealed container dichlorodimethylsilane hydrochloric acid, concentrated, reagent grade isopropanol, distilled from all-glass apparatus methanol, distilled from all-glass apparatus methyl red thylene chloride, distilled from all-glass apparatus petroleum ether, distilled from all-glass apparatus sodium chloride, reagent grade :%(w/v)sodium chloride/water 20%(w/v) sodium chloride/waterTransmittal No. 94-1 (1/94) Form FDA 2905a (6/92) 401–5 Pesticide Analytical Manual Vol. I SECTION 401 C1 LIQUID-LIQUID PARTITIONING AND CHARCOAL/CELITE COLUMN CLEANUP Reference Krause, R.T. (1980) J. Assoc. Off. Anal. Chem. 63, 1114-1124 Principles Residues in aqueous extract are transferred to acetonitrile by liquid-liquid partition￾ing in the presence of sodium chloride. Co-extractives are removed from the acetonitrile solution by partitioning them into petroleum ether, which is discarded. Residues are partitioned from acetonitrile into methylene chloride. Methylene chloride solution is cleaned up on a charcoal/Celite column, and residues are eluted with toluene/acetonitrile. Apparatus chromatographic column, 22 mm id × 300 mm, Teflon stopcock, coarse porosity fritted disc chromatographic column, 25 mm id, plain evaporator, vacuum rotary, as described in E-1 flasks, round-bottom (r-b), 250 and 500 mL, 1 L, Ts 24/40 magnetic stirrer, star, 10 mm diameter × 8 mm height separatory funnel (separator), 250 and 500 mL vacuum adapter, side arm, with Ts 24/40 joints Reagents acetonitrile, distilled from all-glass apparatus; see Section 204 for distillation directions Celite 545 charcoal (Nuchar S-N), produced by Westvaco Corp. and available from Eastman Kodak, Cat. No. 118 0454 1+4 (w/w) charcoal/Celite, combined after each is prepared as directed below; mix thoroughly and store in sealed container dichlorodimethylsilane glass wool, Pyrex hydrochloric acid, concentrated, reagent grade isopropanol, distilled from all-glass apparatus methanol, distilled from all-glass apparatus methyl red methylene chloride, distilled from all-glass apparatus petroleum ether, distilled from all-glass apparatus sodium chloride, reagent grade 2% (w/v) sodium chloride/water 20% (w/v) sodium chloride/water