Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
Talanta. 2012 Apr 15;92:38-44. doi: 10.1016/j.talanta.2012.01.020. Epub 2012 Jan 25.
An ion-paired extraction (IPE) has been developed for the analysis of penicillin antibiotics (penicillin G, oxacillin and cloxacillin) in beef and milk samples using tetrabutylammonium bromide (TBABr) as ion-pairing agent and binary water-acetonitrile as extractant. The factors affecting the IPE efficiency were optimized including solution pH, volume of acetonitrile (ACN), concentration of TBABr and electrolyte salt (NH(4))(2)SO(4). The optimum IPE conditions were 10 mmol L(-1) phosphate buffer pH 8, 2 mL of ACN, 6 mmol L(-1) of TBABr and 2.5 mL of saturated ammonium sulfate. Under the HPLC condition: an Xbridge™ C18 reversed-phase column, isocratic elution of 5 mmol L(-1) phosphate buffer (pH 6.6) and acetonitrile (75:25, v/v) and a flow rate of 1 mL min(-1), with UV detection at 215 nm, the separation of three penicillins was achieved within 10 min. Under the selected optimum conditions, the enhancement of 21-53 folds compared to that without preconcentration and limits of detection (LODs) of 1-2 ng mL(-1) were obtained. Good reproducibility was achieved with RSD<2% for retention time and <5% for slope of calibration curves. The average recoveries higher than 85% were obtained. The proposed IPE-HPLC method has shown to be high efficient preconcentration and analysis method for penicillin residues in beef and milk with LOD lower than the maximum residue limits.
离子对萃取（IPE）已被开发用于使用四丁基溴化铵（TBABr）作为离子对试剂和水-乙腈作为萃取剂分析牛肉和牛奶样品中的青霉素抗生素（青霉素 G、苯唑西林和氯唑西林）。优化了影响 IPE 效率的因素，包括溶液 pH 值、乙腈（ACN）体积、TBABr 浓度和电解质盐（NH4）2SO4。最佳 IPE 条件为 10 mmol L-1 磷酸盐缓冲液 pH 8、2 mL ACN、6 mmol L-1 TBABr 和 2.5 mL 饱和硫酸铵。在 HPLC 条件下：Xbridge™ C18 反相柱，5 mmol L-1 磷酸盐缓冲液（pH 6.6）和乙腈（75:25，v/v）的等度洗脱，流速为 1 mL min-1，UV 检测波长为 215 nm，三种青霉素可在 10 min 内分离。在选定的最佳条件下，与未经预浓缩相比，增强倍数为 21-53 倍，检测限（LOD）为 1-2 ng mL-1。保留时间的 RSD<2%，校准曲线斜率的 RSD<5%，重现性良好。平均回收率高于 85%。该方法已被证明是一种高效的浓缩和分析方法，用于牛肉和牛奶中的青霉素残留，LOD 低于最大残留限量。
