Investigation on gabapentin residues in eggs from free-range hens exposed to saline slags from pharmaceutical industry.

A simple, sensitive and rapid liquid chromatography– tandem mass spectrometry method (LC–MS/MS) was developed and validated to monitor the presence of gabapentin as environmental contaminant in albumen and yolk of eggs from grazing flocks exposed to open air stored saline wastes from pharmaceutical industry. The method involved a simple liquid extraction followed by a gradient elution with formic acid 0.2 % and acetonitrile in reverse phase. ESI ionization was performed in positive ion mode. The tandem mass spectrometer was operated in multiple reaction monitoring mode. The calibration curves were linear in the concentration range from 5 to 400 ng/g for the two matrices with correlation coefficients that exceeded 0.990. The limits of quantitation were 12.0 and 14.8 ng/g in albumen and yolk, respectively. Results are discussed in light of the pharmacokinetics of gabapentin in experimentally exposed hens, accounting for the top soil intake in such free grazing animals.