Hooijerink H, Schilt R, Haasnoot W, Courtheijn D
State Institute for Quality Control of Agricultural Products (RIKILT), Wageningen, The Netherlands.
J Pharm Biomed Anal. 1991;9(6):485-92. doi: 10.1016/0731-7085(91)80250-d.
A method for the determination of clenbuterol in calf urine is described. After a simple two-step sample pretreatment, involving an Extrelut-3 column and a solid-phase extraction column (C2), the separation of clenbuterol from interfering compounds present in urine samples was performed with ion-pair chromatography on a LiChrospher RP-Select-B column with a mixture of acetonitrile and sodium dodecyl sulphate/acetate buffer (pH 3.5) as mobile phase. To obtain a higher specificity, two different physico-chemical detection techniques, i.e. UV-absorption (244 nm) and electrochemical detection (+1250 mV), were applied in series. The lowest limit of determination was 0.5 ng ml-1 and the mean recovery of clenbuterol spiked at 10 ng ml-1 level was 79.9% (RSD = 6.3%; n = 9). The analysis of one urine sample, including sample preparation, took less than 2 h. Results obtained with this method correlated well with GC-MS analysis. With the described method about 400 urine samples were analysed. In a pilot experiment, in which a calf received orally 4 micrograms clenbuterol.HCl per kilogram body weight twice a day (five times the therapeutic dose for oral application) for 5 days, the highest concentration of clenbuterol found in urine was 73 ng ml-1. In a second experiment, in which two calves received the therapeutic dose of clenbuterol.HCl twice a day over a period of 2 weeks, the highest concentration of clenbuterol was 75 ng ml-1 of urine. Eight days after the final application, concentrations of clenbuterol were lower than 0.5 ng ml-1. From this excretion study for clenbuterol a half-life value of approximately 1.5 days was calculated.
本文描述了一种测定小牛尿液中克伦特罗的方法。经过简单的两步样品预处理，即使用Extrelut - 3柱和固相萃取柱（C2），采用离子对色谱法在LiChrospher RP - Select - B柱上，以乙腈和十二烷基硫酸钠/乙酸盐缓冲液（pH 3.5）的混合物作为流动相，将克伦特罗与尿液样品中的干扰化合物分离。为了获得更高的特异性，串联应用了两种不同的物理化学检测技术，即紫外吸收（244 nm）和电化学检测（+1250 mV）。最低检测限为0.5 ng/ml，在10 ng/ml水平加标的克伦特罗平均回收率为79.9%（相对标准偏差 = 6.3%；n = 9）。分析一个尿液样品（包括样品制备）耗时不到2小时。该方法得到的结果与气相色谱 - 质谱分析结果相关性良好。使用所述方法分析了约400个尿液样品。在一项初步实验中，一头小牛每天口服每千克体重4微克盐酸克伦特罗两次（口服治疗剂量的5倍），持续5天，尿液中发现的克伦特罗最高浓度为73 ng/ml。在第二项实验中，两头小牛每天两次接受盐酸克伦特罗治疗剂量，持续2周，尿液中克伦特罗最高浓度为75 ng/ml。末次给药8天后，克伦特罗浓度低于0.5 ng/ml。根据该克伦特罗排泄研究计算出半衰期约为1.5天。
