毛细管电色谱-激发诱导荧光检测动物性食品中多肽类抗生素

以4-氟-7-硝基-2，1，3-苯并呋咱（NBD-F）为荧光试剂，建立了毛细管电色谱-激光诱导荧光（CEC-LIF）检测动物性食品中痕量杆菌肽、多粘菌素B和粘杆菌素等环状多肽抗生素的分析方法。在50 mmol/L的硼酸缓冲液（pH 7.5）中，多肽类抗生素经60℃衍生反应45 min。所得衍生产物采用苯基毛细管色谱填充柱进行分离，流动相为乙腈-磷酸盐缓冲液（pH 5.0，10 mmol/L）（55∶45，v/v），辅助压力为3.8 MPa，分离电压为-10 kV，流速为0.02 mL/min。结果表明，多肽类抗生素的检出限（S/N=3）为5.0~10.0 ng/mL，满足目标物最大残留限量的检测要求。方法应用于饲料和牛奶样品的分析，平均回收率为72.9%~112.4%。该方法预处理操作简单、灵敏，为动物性食品中兽药残留分离分析提供了新手段。

Determination of peptide antibiotics in animal food by capillary electrochromatography coupled with laser induced fluorescence

A rapid and sensitive method was established for the analysis of peptide antibiotics (bacitracin, polymyxin B and colistin) in animal food by capillary electrochromatography (CEC) coupled with laser induced fluorescence (LIF) using 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) as fluorogenic reagent. Peptide antibiotics were derivatized by NBD-F in 50 mmol/L borate buffer (pH 7.5) for 45 min at 60℃. The fluorescence derivatives of peptide antibiotics were separated on a packed phenyl capillary column with a mobile phase consisting of acetonitrile-potassium phosphate (pH 5.0, 10 mmol/L) (55:45, v/v) at the flow rate of 0.02 mL/min. A supplementary pressure of 3.8 MPa and a separation voltage of -10 kV were applied. The limits of detection (LODs, S/N=3) were 5.0-10.0 ng/mL, which fulfilled the requirement of maximum residue limits for examined peptide antibiotics. The method was applied to detect peptide antibiotics in milk and feed stuffs. The spiked recoveries of the three peptide antibiotics were 72.9%-112.4%. The method shows some advantages on the simpler pretreatment and higher sensitivity, which can be of great benefit to the residual analysis of the veterinary drugs.