Solid‐phase extraction of carbaryl and malathion from pond and well water

An analytical method was developed using C 8 solid‐phase extraction columns to extract carbaryl and malathion from well and pond water. Mean percent recovery over a concentration range of 1 μg/L to 10,000 μg/L was consistently between 80 and 100. Well‐water samples fortified with carbaryl and malathion were solid‐phase extracted, and analytes were stored on solid‐phase extraction columns at —4°C for 30 d without significant decomposition. The method was field‐tested by collecting pond water before and after an application of malathion. It provided significantly higher recovery of malathion than a liquid‐liquid extraction procedure.