Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
Talanta. 2010 Apr 15;81(1-2):486-92. doi: 10.1016/j.talanta.2009.12.029. Epub 2009 Dec 28.
A mixed micelle-cloud point extraction (MM-CPE) has been developed for the analysis of penicillin antibiotics (ampicillin, penicillin G, oxacillin, and cloxacillin) in milk samples using Triton X-114 (TX-114) and cethyl trimethylammonium bromide (CTAB) as the mixed micellar extractant. The parameters affecting the MM-CPE that were investigated including solution pH, CTAB concentration, TX-114 concentration, electrolyte salt, equilibration temperature and incubation time. The optimum MM-CPE conditions were: 10 mmol L(-1) phosphate buffer pH 8, 0.06% (w/v) CTAB, 1.5% (w/v) TX-114, and 7% (w/v) Na(2)SO(4), and 5 min equilibration at 40 degrees C. The separation of penicillins was achieved within 8 min under the HPLC conditions: a Vydac C(18) column, isocratic elution of 5 mmol L(-1) phosphate buffer (pH 6.6) and methanol (55:45, v/v), and a flow rate of 1 mL min(-1), with photodiode array detection at 215 and 244 nm. Under the selected condition, the proposed method gave linear calibrations in the range 0.002-10 microg mL(-1) with correlation coefficients greater than 0.999. Limits of detection (LOD) were 2-3 ng mL(-1), and 15-40-fold enhancement compared to that without preconcentration. Good reproducibility was achieved with relative standard deviation <5% for peak area and <3% for retention time. High accuracy, with recoveries higher than 80%, was obtained. The proposed mixed micelle-CPE-HPLC method has shown to be of high potential for the analysis of penicillin residues in milk with LOD comparable to the established maximum residue limits (4-30 ng mL(-1)).
建立了一种浊点萃取-混合胶束萃取（MM-CPE）方法，用于牛奶样品中青霉素类抗生素（氨苄西林、青霉素 G、苯唑西林和氯唑西林）的分析。该方法以 Triton X-114（TX-114）和十六烷基三甲基溴化铵（CTAB）为混合胶束萃取剂。考察了影响 MM-CPE 的参数，包括溶液 pH 值、CTAB 浓度、TX-114 浓度、电解质盐、平衡温度和孵育时间。最佳 MM-CPE 条件为：10mmol·L-1 磷酸盐缓冲液 pH8、0.06%（w/v）CTAB、1.5%（w/v）TX-114 和 7%（w/v）Na2SO4，40℃平衡 5min。在 HPLC 条件下，青霉素可在 8min 内分离：Vydac C18 柱，5mmol·L-1 磷酸盐缓冲液（pH6.6）和甲醇（55:45，v/v）等度洗脱，流速 1mL·min-1，在 215nm 和 244nm 处进行光电二极管阵列检测。在选定的条件下，该方法在 0.002-10μg·mL-1 范围内呈良好的线性，相关系数大于 0.999。检出限（LOD）为 2-3ng·mL-1，与未经预浓缩相比，灵敏度提高了 15-40 倍。峰面积和保留时间的相对标准偏差（RSD）均小于 5%，具有良好的重现性。回收率高于 80%，表明方法具有较高的准确性。该方法具有较高的灵敏度，与已建立的最大残留限量（4-30ng·mL-1）相当，可用于牛奶中青霉素残留的分析。
