Analysis of Veterinary Drugs and Metabolites in Milk Using Quadrupole Time-of-Flight Liquid Chromatography−Mass Spectrometry

Abstract

A quadrupole time-of-flight (Q-TOF) liquid chromatography-mass spectrometry (LC-MS) method was developed to analyze veterinary drug residues in milk. Milk samples were extracted with acetonitrile. A molecular weight cutoff filter was the only cleanup step in the procedure. Initially, a set of target compounds (including representative sulfonamides, tetracyclines, β-lactams, and macrolides) was used for validation. Screening of residues was accomplished by collecting TOF (MS(1)) data and comparing the accurate mass and retention times of found compounds to a database containing information for veterinary drugs. The residues included in the study could be detected in samples fortified at the levels of concern with this procedure 97% of the time. Although the method was intended to be qualitative, an evaluation of the MS data indicated a linear response and acceptable recoveries for a majority of target compounds. In addition, MS/MS data were also generated for the [M + H](+) ions. Product ions for each compound were identified, and their mass accuracy was compared to theoretical values. Finally, incurred milk samples from cows dosed with veterinary drugs, including sulfamethazine, flunixin, cephapirin, or enrofloxacin, were analyzed with Q-TOF LC-MS. In addition to monitoring for the parent residues, several metabolites were detected in these samples by TOF. Proposed identification of these residues could be made by evaluating the MS and MS/MS data. For example, several plausible metabolites of enrofloxacin, some not previously observed in milk, are reported in this study.

Wide-Scope Screening Method for Multiclass Veterinary Drug Residues in Fish, Shrimp, and Eel Using Liquid Chromatography–Quadrupole High-Resolution Mass Spectrometry

“…Subsequently, a standard was purchased, and it was determined that the retention time and product ions also matched that compound. The metabolite desethylene-enrofloxacin (des-ENRO) that had been found earlier in milk samples from cows dosed with ENRO 33 was also found in the catfish dosed with this drug. Thiabendazole was also identified in one regulatory eel sample when the data were compared to the larger veterinary drug database, although the estimated levels were quite low (<1 μ g/kg when compared to a solvent standard).…”

Comparison of three different lipid removal cleanup techniques prior to the analysis of sulfonamide drug residues in porcine tissues

“…That value meets the residue limit of SNs in pork according to EU Council Regulation 470/2009/EC (Council Regulation (EEC) ()) and the U.S. Food and Drug Administration in CFR Title 21 (United States Food & Drug Administration, ). Hence, Q‐TOF/MS is capable of performing high‐throughput screening for daily monitoring of those compounds with higher residue limits (Turnipseed, Storey, Clark, & Miller, ).…”

High-throughput method for macrolides and lincosamides antibiotics residues analysis in milk and muscle using a simple liquid–liquid extraction technique and liquid chromatography–electrospray–tandem mass spectrometry analysis (LC–MS/MS)

“…The NRCP is an attribution of Ministry of Agriculture, Livestock and Food Supply (MAPA) [9,10]. Many studies have reported methodologies based on liquid chromatography couple to mass spectrometry in single or tandem mode (LC-MS and LC-MS/MS, respectively) to determine macrolides and lincosamides residues in milk [11][12][13][14] and muscle [15][16][17][18][19][20][21], and also in different matrices, such as honey [22,23], eggs [24], fish [25] and kidney [26,27]. These compounds are routinely included in multiresidue methodologies [14,16,19,[22][23][24][28][29][30][31], and there is minor publications of macrolides class only [32,33] or macrolides and lincosamides only [21].…”