Chou Su-Lien, Yang Mo-Hsiung, Ling Yong-Chien, Giang Yun-Seng
Department of Nuclear Science, National Tsing Hua University, Hsinchu 30043, Taiwan, ROC.
J Chromatogr B Analyt Technol Biomed Life Sci. 2004 Jan 5;799(1):37-50. doi: 10.1016/j.jchromb.2003.10.009.
An analytical scheme using gas chromatography (GC)-isotope dilution mass spectrometry (MS) assisted by precedent liquid-liquid extraction (LLE) and chemical derivatization (ChD) is described for the simultaneous determination of ketamine (KT) and its major metabolite, norketamine (NK), in urine. The simultaneous ChD of the two analytes, one primary amine and one secondary amine, with pentafluorobenzoyl chloride (PFBC) has not only enhanced their instrumental responses and mass-spectrum uniqueness but also afforded more proper yet easier selection of qualifier and quantifier ions and hence achieved more evidential identification and quantitation. Thus, the regression calibration curves for KT and NK in urine are linear within 100-5000 ng/ml, with correlation coefficients typically exceeding 0.99 and NK curves exclusively showing larger slopes than KT curves. The method limits of detection (LODs) determined by two definitions for KT and NK range from 3 to 75 ng/ml, and limits of quantitation (LOQs) from 9 to 100 ng/ml. The mean recoveries (N = 3) calculated for the LLE/ChD of KT and NK from 50 and 100 microl, respectively, of a 100 microg/ml urinary spike vary from 71.0 to 97.8%, with NK consistently giving better recoveries than KT. The precisions (N = 3) calculated for the total analyses of four real-case samples are typically below 12.3%. GC-MS operated in the positive ion chemical ionization (PCI) mode can offer both qualitative and quantitative information complementary to those given by the EI mode. The proposed scheme is simple, effective, reliable, and robust. It may serve as a confirmatory protocol for forensic urine drug testing.
本文描述了一种分析方案，该方案采用气相色谱（GC）-同位素稀释质谱（MS），并辅以液-液萃取（LLE）和化学衍生化（ChD），用于同时测定尿液中的氯胺酮（KT）及其主要代谢物去甲氯胺酮（NK）。两种分析物（一种伯胺和一种仲胺）与五氟苯甲酰氯（PFBC）同时进行化学衍生化，不仅增强了它们的仪器响应和质谱独特性，还能更合理且更容易地选择定性和定量离子，从而实现更可靠的鉴定和定量。因此，尿液中KT和NK的回归校准曲线在100 - 5000 ng/ml范围内呈线性，相关系数通常超过0.99，且NK曲线的斜率始终大于KT曲线。通过两种定义确定的KT和NK的方法检测限（LOD）范围为3至75 ng/ml，定量限（LOQ）范围为9至100 ng/ml。分别从100 μg/ml尿液加标样中取50 μl和100 μl进行LLE/ChD后计算得到的KT和NK的平均回收率（N = 3）在71.0%至97.8%之间，NK的回收率始终高于KT。对四个实际案例样本进行总分析计算得到的精密度（N = 3）通常低于12.3%。以正离子化学电离（PCI）模式运行的GC-MS可提供与EI模式互补的定性和定量信息。所提出的方案简单、有效、可靠且稳健。它可作为法医尿液药物检测的确认方案。
