Schaffer Michael I, Wang Wen-Ling, Irving John
Psychemedics Corporation, Culver City, California 90230, USA.
J Anal Toxicol. 2002 Oct;26(7):485-8. doi: 10.1093/jat/26.7.485.
In order to evaluate the effectiveness of a wash procedure using isopropanol followed by multiple extended phosphate buffer washes as compared with a methanol wash procedure previously reported, a contamination experiment was designed involving the soaking of human head hair in cocaine-contaminated aqueous solutions. Fourteen negative human head hair samples were soaked in a solution of cocaine HCl (1000 ng/mL) at room temperature for 1 h, then rinsed with distilled water and dried at room temperature. Using the extensive wash procedures (15-min isopropanol wash, followed by three 30-min phosphate buffer washes and then two 60-min washes), in no case would any of the samples be reported out as positive at a cut-off of 5 ng cocaine/ 10 mg hair. With the methanol procedure, 8 of the 14 methanol-washed samples exceeded a cut-off of 5 ng/10 mg hair. Extensive washing was shown to be far more effective for removal of external contamination than the methanol wash procedure reported. In all cases, the extensive aqueous wash protocol would allow the differentiation of ingestion versus external contamination, as defined by this soaking experiment. All samples underwent solid-phase extraction and derivatization followed by liquid chromatographic-tandem mass spectrometric analysis. Analysis was performed on a triple quadrupole API 2000 PerkinElmer Sciex mass spectrometer (MS) equipped with an atmospheric pressure ionization source via an ion spray interface. The MS operated in the positive Cl multiple reaction mode.
为了评估使用异丙醇清洗程序并随后进行多次延长的磷酸盐缓冲液清洗与先前报道的甲醇清洗程序相比的有效性，设计了一项污染实验，该实验涉及将人类头发浸泡在受可卡因污染的水溶液中。将14个阴性人类头发样本在室温下浸泡在盐酸可卡因溶液（1000 ng/mL）中1小时，然后用蒸馏水冲洗并在室温下干燥。使用广泛的清洗程序（15分钟异丙醇清洗，然后三次30分钟磷酸盐缓冲液清洗，再进行两次60分钟清洗），在任何情况下，均不会有任何样本在可卡因截止值为5 ng/10 mg头发时被报告为阳性。采用甲醇清洗程序时，14个经甲醇清洗的样本中有8个超过了5 ng/10 mg头发的截止值。结果表明，广泛清洗在去除外部污染方面比所报道的甲醇清洗程序有效得多。在所有情况下，如本浸泡实验所定义，广泛的水洗方案将能够区分摄入与外部污染。所有样本均经过固相萃取和衍生化，然后进行液相色谱-串联质谱分析。分析在配备大气压电离源并通过离子喷雾接口的三重四极杆API 2000珀金埃尔默Sciex质谱仪（MS）上进行。MS以正离子模式的多反应监测模式运行。
