Solid phase extraction of 2,4-D from human urine

A method for determining urinary concentrations of 2,4-D in samples collected from non-occupationally, environmentally exposed individuals was developed. The 2,4-D was extracted from fortified human urine samples using octadecylsilane solid phase extraction cartridges. The average percent recovery for urine samples spiked at 2 and 20 nglmL was 100% and 93%, respectively. The method detection limit was estimated to be 0.75 ng of 2,4-D per mL of urine based on a 10 mL sample size. The potential use of 2,4-dichlorophenylacetic acid as a surrogate standard was also investigated.