A microextraction by packed sorbent (MEPS) procedure for rapid concentration of methadone and its primary metabolite (EDDP) in hair samples was developed. The miniaturized approach coupled to gas chromatography with tandem mass spectrometry (GC–MS-MS) was successfully validated. Hair samples (50 mg) were incubated with 1 mL of 1 M sodium hydroxide for 45 min at 50°C, time after which the extract was neutralized by adding 100 μL of 20% formic acid. Subsequently, MEPS was applied using a M1 sorbent (4 mg; 80% C8 and 20% strong cation-exchange (SCX)), first conditioned with three 250-μL cycles of methanol and three 250-μL cycles of 2% formic acid. The extract load occurred with nine 150-μL cycles followed by a washing step involving three 50-μL cycles with 3.36% formic acid. For the elution of the analytes, six 100-μL cycles of 2.36% ammonium hydroxide in methanol were applied. The method was linear from 0.01 to 5 ng/mg, for both compounds, presenting determination coefficients greater than 0.99. Precision and accuracy were in accordance with the statements of international guidelines for method validation. This new miniaturized approach allowed obtaining recoveries ranging from 73 to 109% for methadone and 84 to 110% for EDDP, proving to be an excellent alternative to classic approaches, as well as other miniaturized procedures.

中文翻译：

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填充吸附剂的微萃取是一种测定头发中美沙酮和乙二醛的新方法。

开发了一种通过填充吸附剂（MEPS）进行微萃取的方法，用于在头发样品中快速浓缩美沙酮及其主要代谢物（EDDP）。与气相色谱串联质谱联用（GC-MS-MS）的小型化方法已成功验证。将毛发样品（50 mg）与1 mL 1M氢氧化钠在50°C下孵育45分钟，然后通过添加100μL20％甲酸中和提取物。随后，使用M1吸附剂（4 mg； 80％C8和20％强阳离子交换（SCX））施加MEPS，首先用三个250μL甲醇循环和三个250μL2％甲酸循环进行调节。萃取物负载以9个150μL循环进行，随后是洗涤步骤，其中包含3个50μL循环和3.36％甲酸。为了洗脱分析物，六个100-μL循环为2。施加36％的氢氧化铵的甲醇溶液。对于两种化合物，该方法的线性范围为0.01至5 ng / mg，测定系数大于0.99。准确性和准确性符合国际方法验证指南的要求。这种新的小型化方法可使美沙酮的回收率达到73％至109％，EDDP的回收率达到84％至110％，事实证明，它是经典方法以及其他小型化方法的极佳替代方案。