Collins S, O'Keeffe M, Smyth M R
National Food Centre (Teagasc), Dunsinea, Castleknock, Dublin, Ireland.
Analyst. 1994 Dec;119(12):2671-4. doi: 10.1039/an9941902671.
A method is described for the extraction of four beta-agonists, clenbuterol, salbutamol, mabuterol and terbutaline from bovine urine and liver samples using radioimmunoassay (RIA) as the method of determination. Following enzymic digestion of the liver samples using protease enzyme, the digest is centrifuged and the harvested supernatant is saturated with sodium chloride and adjusted to pH 11.0. An ethyl acetate-propan-2-ol mixture is used to extract the beta-agonists from the liver digest. The samples of urine and liver extracts are adjusted to pH 6.0 and applied to mixed phase (XtrackT) columns. The column is washed with water and methanol and the beta-agonists are eluted with methanol containing 2% ammonia. After evaporation of the eluting solvent and reconstitution in ethanol the beta-agonist residues are determined by RIA, with standard graphs prepared in residue-free sample extract. The procedure has been validated for clenbuterol, salbutamol, mabuterol and terbutaline. The mean recovery of the beta-agonists from urine and liver is > 75% and > 85%, respectively. The detection limit is 0.13 ng ml-1 and 0.46 ng g-1 of clenbuterol in urine and liver, respectively. The high recoveries attained for both types of beta-agonists are a result of an efficient liquid-liquid extraction step coupled with a selective mixed solid-phase extraction procedure.
本文描述了一种从牛尿液和肝脏样本中提取四种β-激动剂（克伦特罗、沙丁胺醇、马布特罗和特布他林）的方法，采用放射免疫分析法（RIA）作为测定方法。使用蛋白酶对肝脏样本进行酶消化后，将消化液离心，收集的上清液用氯化钠饱和并调节至pH 11.0。用乙酸乙酯 - 异丙醇混合物从肝脏消化液中提取β-激动剂。将尿液和肝脏提取物样本调节至pH 6.0，并应用于混合相（XtrackT）柱。用蒸馏水和甲醇冲洗柱子，并用含2%氨的甲醇洗脱β-激动剂。洗脱溶剂蒸发后用乙醇复溶，通过RIA测定β-激动剂残留量，标准曲线在无残留样本提取物中制备。该方法已针对克伦特罗、沙丁胺醇、马布特罗和特布他林进行了验证。β-激动剂从尿液和肝脏中的平均回收率分别> 75%和> 85%。尿液和肝脏中克伦特罗的检测限分别为0.13 ng/ml和0.46 ng/g。两种类型的β-激动剂均获得高回收率是高效液 - 液萃取步骤与选择性混合固相萃取程序相结合的结果。
