Multiresidue Method for the Determination of Quinolone Antibiotics in Bovine Raw Milk by Capillary Electrophoresis−Tandem Mass Spectrometry

Abstract

A new analytical method based on capillary zone electrophoresis-tandem mass spectrometry (CZE-MS/MS) is proposed and validated for the identification and simultaneous quantification of eight quinolones for veterinary use in bovine raw milk. The studied quinolones include danofloxacin, sarafloxacin, ciprofloxacin, marbofloxacin, enrofloxacin, difloxacin, oxolinic acid, and flumequine, whose contents are regulated by the EU Council Regulation no. 2377/90 in animal edible tissues. Different parameters (i.e., separation buffer composition and electrospray conditions) were optimized in order to obtain both an adequate CE separation and a high sensitivity, using experimental design methodology to consider the interactions among the studied variables. MS/MS experiments using an ion trap as analyzer operating in the multiple reaction monitoring mode were carried out to achieve the minimum number of identification points according to the 2002/657/EC European Decision. For the quantification in bovine raw milk samples, a two-step solid-phase extraction procedure was developed using Oasis MAX and HLB cartridges without protein precipitation. Satisfactory results were obtained in terms of linearity (r2 between 0.989 and 0.992) and precision (RSD below 18%). The limits of detection and quantification (below 6 and 24 ppb, respectively) were in all cases lower than the maximum residues limits tolerated for these compounds in milk, the recoveries ranging from 81 to 110%, indicating the potential of the CZE-MS/MS for the analysis of regulated quinolone antibiotics in the food quality and safety control areas.

Effective Separation and Simultaneous Determination of Four Fluoroquinolones in Milk by CE with SPE

“…, respectively, for the same fluoroquinolones. The detection limits of the proposed method were lower than those for LC [9] and CE [15,16,18,19], and higher or close to those for LC-MS-MS [12] or SPE-LC-MS-MS [20]. The obtained detection limits of the fluoroquinolones studied permit the detection in milk samples at the targeted MLRs.…”

“…Dichloromethane has been used to extract ciprofloxacin and enrofloxacin from chicken muscle tissue samples with reported recoveries of 74 and 54% for enrofloxacin and ciprofloxacin, respectively [23]. A two-step solid-phase extraction procedure was developed by Lara et al [20] using Oasis MAX and HLB cartridges without protein precipitation. In our previous work, acetonitrile was used for protein precipitation and extraction of seven quinolones in porcine tissue [19].…”

“…To increase the selectivity and sensitivity of CE, solid phase extraction (SPE) has been combined with CE for the determination of fluoroquinolones in plasma samples with detection limits of 2.2 mg L -1 for ciprofloxacin and 1.6 mg L -1 for flumequine [15], ciprofloxacin and its impurities with the detection limit of 1 mg L -1 [16], flumequine and oxolinic acid in chicken tissues with detection and quantification limits of 10 and 30 lg kg -1 for flumequine [17], ciprofloxacin, enrofloxacin and flumequine in pig plasma samples with the detection limits of 70, 85 and 50 lg L -1 , respectively [18], and quinolones residues in porcine tissue with the detection limit of 40 lg kg -1 for ciprofloxacin and 35 lg kg -1 for enrofloxacin [19]. However there are only few reports of SPE-CE for the detection of quinolone residues in milk samples [20]. A novel analytical method based on capillary zone electrophoresis-MS-MS was proposed for the identification and simultaneous quantification of eight quinolones in bovine raw milk with limits of detection and quantification below 6 and 24 lg L -1 , respectively [20].…”

“…However there are only few reports of SPE-CE for the detection of quinolone residues in milk samples [20]. A novel analytical method based on capillary zone electrophoresis-MS-MS was proposed for the identification and simultaneous quantification of eight quinolones in bovine raw milk with limits of detection and quantification below 6 and 24 lg L -1 , respectively [20]. This method has low detection limits, but requires an expensive instrument.…”

Highly sensitive detection of five typical fluoroquinolones in low‐fat milk by field‐enhanced sample injection‐based CE in bubble cell capillary

“…It is necessary to develop analytical methods that are sensitive enough to monitor and determine these antibiotics at such a low level in bovine milk. Different strategies have been carried out to monitor residual levels of FQs in bovine milk including immunoassays [8][9][10], HPLC with optical [11][12][13] or MS [3,14] detection, and CE with electrochemical [15], UV [16,17], or MS [18,19] detection. Owing to its limitation in sensitivity, CE is not so commonly used as HPLC in the field of multiresidue separation and detection.…”