Multiresidue method for the determination of 32 human and veterinary pharmaceuticals in soil and sediment by pressurized-liquid extraction and LC-MS/MS

Abstract

An analytical chemical method has been developed for the simultaneous determination of 32 different pharmaceuticals in soils and sediments. The pharmaceuticals cover a varity of different compound groups. Soil samples were extracted with different solvents with the help of pressurized-liquid extraction (PLE) followed by clean-up using a solid-phase extraction (SPE) procedure. The purified extracts were analyzed by LC-MS/MS. The extraction method was evaluated by testing the following variables: extraction solvents, solvent pH, and temperature. Applying 20 g of soil/sediment and extracting with a mixture of methanol with aqueous ammonia solution (0.1 mol L(-1)) at 80 degrees C for 5 min in five cycles provided satisfactory recoveries between 66 and 114% with SD of between 1 and 14%. For preconcentration and purification tandem MAX-HLB cartridges were used. The volume and composition was optimized and the highest recoveries were obtained with a combination of methanol-aqueous ammonia solution. The limits of quantification (LOQs) were between 0.2 and 2 ng g(-1) and linearity higher than 0.98 for the majority of the selected pharmaceuticals. The method was successfully applied to soil samples collected from the Jerez de la Frontera agricultural region, irrigated with treated wastewater, and to sediment samples from the River Guadalete. The detection of nine pharmaceuticals including stimulants, antirheumatics, analgesics, anti-inflammatories, tranquilizers, and veterinary medicines at ng g(-1) concentration levels was achieved.