Determination of chloramphenicol residues in shrimps by liquid chromatography-mass spectrometry.

A liquid chromatographic method with mass spectrometric detection and identification (LC-MS) is presented for the determination of chloramphenicol (CAP) in shrimp tissues. Homogenized shrimp samples were extracted with phosphate buffer (pH 7.0). Clean-up was carried out on a C(18) SPE cartridge. Chloramphenicol was determined by LC-MS-ESI in negative mode. The column used was a Symmetry Shield with a mixture of acetonitrile-water (25:75) as mobile phase. Shrimp samples were fortified at CAP levels between 0.2 and 50 ng g(-1) with 5D-CAP as internal standard. At these levels, accuracies lay between 101 and 110% and between-day reproducibilities were lower than 7.1%, expressed as the variation coefficient of the mean. Limit of decision (CCalpha) was 0.02 ng g(-1). Limit of quantitation (LOQ) was 0.2 ng g(-1).