尿中氯胺酮及其代谢物盘鉴和GC/MS/SIM测定

目的 研究尿中氯胺酮(KET)及其代谢物去甲基氯胺酮(NKET)的盘鉴(Disk SPE)。方法 用含有化学键合C18和强酸型强阳离子交换(SCX)基团的萃取柱SPEC.C18 AR/MP3萃取,加入萃取柱前的尿样用0.1mol/L磷酸盐缓冲溶液(pH 6)稀释,洗脱溶剂为含2％(v/v)氨水的乙酸乙酯;以2,4,6-三硝基甲苯(TNT)为色谱内标,GC/MS/SIM检测。结果 在加标量为0.5μg/mL、2μg/mL和6μg/mL的控制尿样中,KET和NKET的平均回收率分别为91.5％和79.9％,6次测定的RSD均为8.7％;线性范围0.02-8μg/mL,线性相关系数分别为0.9819和0.9964;检出限(S/N=3)分别为6ng/mL和4ng/mL;总离子色谱图背景低,杂质少。同一根萃取柱重复使用8次以上未见性能下降;嫌疑尿样中检出KET和/或NKET,和常规的液液萃取结果相符。结论 该方法适用于尿中KET和NKET的同时测定。

Determination of ketamine and norketamine in urine samples by disk solid phase extraction and gas chromatography-mass spectrometry in selected ion monitoring

Objective Disk solid phase extraction ( SPE) was assessed for ketamine ( KET) and its major metabolite norketamine ( NKET) from urine samples. Methods The SPE was performed with SPEC. C18 AR/MP3 Disk SPE cartridge, offering hydrophobic (C18) and strong cation ionic exchange (SCX) interactions for the analytes. Sample was diluted in 0. 1mol/L phosphate buffer ( pH 6) prior to SPE, and ethyl acetate added with 2% (v/v) ammonia was used to elute analytes from the disk. Gas chromatography-mass spectrometry in selected ion monitoring (GC/MS/SIM) was performed for detection, in which 2, 4, 6-trinitrotoluene (TNT) was used as chromatographic standard. Results The average recoveries of KET and NKET in positive control samples spiked at 0. 5μg/mL, 2μg/mL and 6 μg/mL levels were 91. 5% and 79. 9% , with relative standard deviations ( RSDs, n =6) of 8. 7% . The linearity covered in range of 0. 02 - 8μg/mL, and correlation coefficients ( r ) were 0. 9964 and 0. 9819 in linear regression, and the limits of detection (LODs, S/N =3) were 6ng/mL and 4ng/mL for KET and NKET, respectively. Few impurities occurred in total ion chromatogram ( TIC ) . Performance of the same cartridge did not deteriorate in eight successive replicate tests. The results of real samples by this method were in good agreement with those of conventional liquid-liquid extraction method. Conclusion This method is suitable for simultaneous determination of KET and NKET in urine samples.