Liquid Chromatography–Mass Spectrometry Method for the Quantitative Determination of Residues of Selected Veterinary Hormones in Powdered Ingredients Derived from Bovine Milk

Abstract

A rugged, quantitative liquid chromatography-tandem mass spectrometry method with modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample preparation for 17 selected veterinary hormones in six different powdered ingredients derived from bovine milk was developed and comprehensively validated. A universal post-extraction spiked matrix-matching approach based on whole milk powder has been successfully implemented. Three validation runs based on four levels of pre-extraction spiked quality control (QC) samples have been conducted. Overall accuracy (86-117%), overall precision (<20% RSD), selectivity, absolute extraction recovery (62-82%), matrix effect (<15% for most compounds), limits of detection (0.1-0.8 μg/kg, except for diethylstilbestrol at 3.8 μg/kg), limits of quantitation (0.2-2.0 μg/kg, except for diethylstilbestrol at 10.0 μg/kg), and extract stability (48 h) have been determined. The method is proposed for the routine analysis of hormones potentially present in powdered ingredients derived from bovine milk.