Matrix Solid-Phase Dispersion Extraction and Capillary Electrophoresis Determination of Tetracycline Residues in Milk

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Matrix Solid-Phase Dispersion Extraction and Capillary Electrophoresis Determination of Tetracycline Residues in Milk Guangfen Mu & Huitao Liu & Lina Xu & Lihua Tian & Feng Luan

Received: 1 December 2010 / Accepted: 2 March 2011 / Published online: 1 April 2011 # Springer Science+Business Media, LLC 2011

Abstract A capillary zone electrophoresis method was proposed for simultaneous detection and quantification of three tetracycline antibiotics in commercial milk samples, i.e., tetracycline, oxytetracycline, and doxycycline. The influences of the electrolyte composition, pH, as well as temperature and applied voltage on separation were investigated. The optimal running buffer was 30 mM Na2HPO4 and 1 mM EDTA at pH 11.5, with 3 s hydrodynamic injection, 25 kV applied voltage, and UV detection at 268 nm. Matrix solid-phase dispersion procedure was used for sample pretreatment. Several solid support materials were investigated, and silica with bonded C18 chains (C18) was used as sorbent. Electrophoretic analysis was completed in less than 6 min, with LODs ranging from 0.0745 μg/mL for oxytetracycline to 0.0808 μg/mL for doxycycline. The recoveries obtained were between 93.4% and 102%. Keywords Capillary zone electrophoresis . Tetracycline antibiotic . Milk . Matrix solid-phase dispersion

Introduction The tetracycline antibiotic (TC) is a kind of broad-spectrum antibiotic produced by the Actinomycetes. TCs are divided into two types: natural products (tetracycline (TC), chlortetracycline, oxytetracycline (OTC), and demeclocycline) and semi-synthetics products (doxycycline (DC), methacycline, G. Mu : H. Liu (*) : L. Xu : L. Tian : F. Luan Department of Applied Chemistry, Yantai University, Yantai 264005, People’s Republic of China e-mail: [email protected]

minocycline, and meclocycline, etc.). TCs are commonly applied to food-producing animals as veterinary medicines because of the broad-spectrum activity against pathogenic microorganisms, relatively low degree of toxicity, and low cost. TCs have played an important role in the breeding industry, which are widely used to suppress bacterial infection and in the prevention and control of animal diseases (Meng et al. 2007). The TC antibiotics are licensed for use in a variety of food-producing animals, including cattle, pig, poultry, and fish (Pastor-Navarro et al. 2009). However, the presence of TC antibiotic residues in food has harmful effects on consumers’ health, such as allergic reactions, liver damage, yellowing of teeth, and gastrointestinal disturbance (Czeizel et al. 1998), so many countries have set maximum residue limits (MRLs). In the USA, the MRLs of TC for all food-producing species are 2 mg/kg in muscle, 6 mg/kg in liver, and 12 mg/kg in kidney (US Food and Drug Administration 2003). EU clearly stipulates that the total content of TCs shall not exceed 100 μg/kg for milk and 200 μg/kg for eggs (European Commission 1999???). Food safety problems caused by antibiotic residues in animalorigin foods have drawn more and more attention, and the testing and analysi