液相色谱法快速测定鸡肉中氧氟沙星手性对映体残留量

建立了鸡肉样品中氧氟沙星对映体液相色谱荧光检测(liquid chromatography fluorescence detector,LC-FLD)残留量快速分析方法。鸡肉样品经磷酸盐缓冲液提取后,用C18固相萃取小柱净化,洗脱液吹干后用流动相复溶即可进行液相色谱分析。分析时采用LeapsilTM C18色谱柱,以水相(含2 mmol/L硫酸铜和2.5 mmol/L异亮氨酸,pH3.5)和甲醇作为流动相进行梯度分析,荧光检测器检测,其中激发波长为297 nm,发射波长为487 nm,外标法定量。本方法在5.0、50、100μg/kg和150μg/kg 4个添加水平下,左氧氟沙星对映体平均添加回收率在75.5%～86.1%之间,批内变异系数在1.97%～4.42%之间,批间变异系数在3.02%～6.02%之间;右氧氟沙星对映体平均添加回收率在77.3%～84.9%之间,批内变异系数在2.15%～4.21%之间,批间变异系数在3.87%～5.84%之间。方法对两种对映体的检测限均为1.5μg/kg,定量限均为5.0μg/kg。

Determination of Residual Ofloxacin Enantiomers in Chicken Muscle by Liquid Chromatography

A method was developed for determining residual ofloxacin enantiomers in chicken muscle by liquid chromatography with fluorescence detection. Samples were extracted with phosphate buffer solution. The extract was purified by solid phase extraction （SPE） using a C18 cartridge and the eluent was then dried by nitrogen blowing and dissolved in mobile phase. The analytes were separated on a LeapsilTM C18 column using a mobile phase composed of a mixture of methanol and aqueous solution of （pH 3.5） 2 mmol/L copper sulfate and 2.5 mmol/L isoleucine. Excitation wavelength was 297 nm and emission wavelength was 487 nm. Quantitation was performed by using the external standard calibration method. The average recoveries for the two enantiomers in spiked chicken muscle were 75.5%-86.1%at four fortiifed levels ranging from 5 to 150μg/kg, and the intra-and inter-batch coefifcients of variation （CVs） were 2.15%-4.21%and 3.87%-5.84%, respectively. The limits of detection （LOD） and quantitation （LOQ） were 1.5 and 5.0μg/kg for the two enantiomers of olfoxacin, respectively.