Ultra-high performance liquid chromatography-tandem mass spectrometry for the analysis of phenicol drugs and florfenicol-amine in foods

Abstract

A method based on ultra-high performance liquid chromatography (UHPLC) is proposed for the determination of chloramphenicol (CAP), its related compounds, thiamphenicol (TAP) and florfenicol (FF), and the polar metabolite florfenicol-amine (FFA), in animal-derived foods (chicken and pork meat, fish, prawns and honey). For the retention of FFA and its simultaneous analysis with the parent compounds a phenyl–hexyl column is proposed. A fast separation is achieved in less than 2 minutes using a methanol : acetic acid–ammonium acetate buffer (5 mM, pH 5) and gradient elution. Under these conditions, the FFA is retained at more than twice the dead volume, as recommended by the legislation. For the coupling with mass spectrometry, heated-electrospray (H-ESI) is used as ionisation source improving vaporization efficiency. To prevent interferences using selected-reaction monitoring (SRM) both quantitation and confirmation transitions were carefully selected. Two different sample treatments based on solid-phase extraction with mixed-mode cartridges for fish and meat products and hydrophilic–lipophilic-balanced cartridges for honey are proposed, providing limits of quantitation (LOQs) below μg kg⁻¹ level.