Perkins S L, Livesey J F, Escares E A, Belcher J M, Dudley D K
Department of Laboratory Medicine, Ottawa Civic Hospital, Canada.
Clin Chem. 1991 Nov;37(11):1989-93.
Cotinine is a sensitive and specific biochemical marker of exposure to cigarette smoke. We describe a simple solid-phase extraction of cotinine from plasma before quantification by HPLC. Extraction recovery was 97.9% +/- 11.0% for plasma concentrations of 5-400 micrograms/L. Baseline separation of cotinine and caffeine was achieved within 11 min of injection onto a C18 reversed-phase column. The mobile phase was citric acid/dibasic potassium phosphate (30 mmol/L each, pH 6.0) containing 100 mL of acetonitrile per liter. Within-day and day-to-day precision (CV) were 4.7% and 8.4%, respectively. We also describe a modification of the Nicotine Metabolite RIA kit (Diagnostic Products Corp.) for quantifying cotinine in plasma. Recovery of cotinine from supplemented plasma was within 10% of the expected value with this RIA kit. Interassay precision averaged 8.1% for samples in the range 50-400 micrograms/L; intra-assay precision averaged 3.6% at 230 micrograms/L and 8.7% at 53 micrograms/L. Correlation between the two methods was RIA = 1.13 HPLC + 14.8 (n = 128, r = 0.957, P less than 0.001). Both methods are technically simple to perform.
可替宁是接触香烟烟雾的一种敏感且特异的生化标志物。我们描述了一种在通过高效液相色谱法（HPLC）定量之前从血浆中简单固相萃取可替宁的方法。对于血浆浓度为5 - 400微克/升的情况，萃取回收率为97.9%±11.0%。将样品注入C18反相柱后，11分钟内实现了可替宁和咖啡因的基线分离。流动相为柠檬酸/磷酸氢二钾（各30毫摩尔/升，pH 6.0），每升含有100毫升乙腈。日内和日间精密度（CV）分别为4.7%和8.4%。我们还描述了对尼古丁代谢物放射免疫分析试剂盒（诊断产品公司）的一种改进，用于定量血浆中的可替宁。使用该放射免疫分析试剂盒，从添加了可替宁的血浆中回收的可替宁在预期值的10%以内。对于50 - 400微克/升范围内的样品，批间精密度平均为8.1%；在230微克/升时批内精密度平均为3.6%，在53微克/升时批内精密度平均为8.7%。两种方法之间的相关性为放射免疫分析 = 1.13×高效液相色谱 + 14.8（n = 128，r = 0.957，P＜0.001）。两种方法在技术上都易于操作。
