Evaluation of Quechers Method for Simultaneous Determination of Multi-Pharmaceutical Residues in Plants.

Field application of biosolids to agricultural land and irrigation using reclaimed water results in the accumulation of pharmaceuticals in agricultural produce. This has raised concern on the impact to human health after a long-term consumption of pharmaceutical-contaminated vegetables. Several analytical methods have been developed to identify and quantify the pharmaceuticals accumulated in plants. In this study we compared the commonly used accelerated solvent extraction (ASE) with the quick, easy, cheap, effective, rugged, and safe QuEChERS method. The extracted pharmaceuticals were quantitated using a liquid chromatography coupled to tandem mass spectrometry. The results revealed that the pharmaceutical extraction efficiencies from celery and lettuce for both ASE and QuEChERS methods were all >70% with relative standard deviation (RSD) < 20% (n=3). The method detection limits (MDLs) of ASE ranged from 1.9 to 15.8 µg kg^-1 while the MDLs of QuEChERS method were lower and ranged from 0.7 to 8.0 µg kg^-1. The established QuEChERS method was then applied to determine pharmaceutical uptake in lettuce and celery growing hydroponically. These results provide the information needed to assess the potential risks to food safety and human health.