UTILIZATION OF SOLID-PHASE EXTRACTION AND REVERSED-PHASE AND ION-PAIR CHROMATOGRAPHY IN THE ANALYSIS OF 7 AGROCHEMICALS IN WATER

Six herbicides (2, 4-D, 2, 4-DP, 2, 4-DIOE, 2, 4-DPBEE, dicamba, pendimethalin) and the insecticide chlorpyrifos were solid-phase (C8) extracted from 100 mL of water (adjusted to pH 2. 2) that was collected from turfgrass run-off test plots. 2, 4-D, 2, 4-DP, and dicamba were analyzed by ion-pair HPLC utilizing a C18 column, a mobile phase of methanol-water (0. 005 M octyltriethylammonium phosphate) (55: 45) and UV detection at 230 nm. Pendimethalin, chlorpyrifos, and the two esters 2, 4-DIOE and 2, 4-DPBEE were quantified with HPLC utilizing a C18 column, methanol-water (82: 18) mobile phase, and UV detection at 230 nm. The minimum detection limit per 25-μL injection was 4-33. 3 ng of chemical, which corresponds to a concentration of 2. 4-20. 0 ppb. Average overall recoveries: dicamba, 82. 2%; 2, 4-D, 93. 8%; 2, 4-DP, 103. 0%; chlorpyrifos, 93. 7%; 2, 4-DPBEE, 100. 0%; 2, 4-DIOE, 92. 0%; pendimethalin, 91. 5%. © 1990, American Chemical Society. All rights reserved.