Forensic Genetics & Chemistry Division, Supreme Prosecutors' Office, Seoul 06590, Korea.
Molecules. 2019 Jul 9;24(13):2501. doi: 10.3390/molecules24132501.
Sample preparation is an important step in the isolation of target compounds from complex matrices to perform their reliable and accurate analysis. Hair samples are commonly pulverized or processed as fine cut, depending on preference, before extraction by techniques such as solid-phase extraction (SPE), liquid-liquid extraction, and other methods. In this study, a method based on hybrid solid-phase extraction (hybridSPE) and gas chromatography-mass spectrometry (GC-MS) was developed and validated for the determination of methamphetamine (MA) and amphetamine (AP) in hair. The hair samples were mechanically pulverized after washing with de-ionized water and acetone. The samples were then sonicated in methanol at 50 °C for 1 h and centrifuged at 50,000× for 3 min. The supernatants were transferred onto the hybridSPE cartridge and extracted using 1 mL of 0.05 M methanolic hydrogen chloride. The combined solutions were evaporated to dryness, derivatized using pentafluoropropionic anhydride, and analyzed by GC-MS. Excellent linearity (R > 0.9998) was achieved in the ranges of 0.05-5.0 ng/mg for AP and 0.1-10.0 ng/mg for MA. The recovery was 83.4-96.8%. The intra- and inter-day accuracies were -9.4% to 5.5% and -5.1% to 3.1%, while the intra- and inter-day precisions were within 8.3% and 6.7%, respectively. The limits of detections were 0.016 ng/mg for AP and 0.031 ng/mg for MA. The validated hybridSPE method was applied to dyed hair for MA and AP extraction and compared to a methanol extraction method currently being used in our laboratory. The results showed that an additional hybridSPE step improved the recovery by 5.7% for low-concentration quality control (QC) samples and by 24.1% for high-concentration QC samples. Additionally, the hybridSPE method was compared to polymeric reversed-phase SPE methods, and the absolute recoveries for hybridSPE were 50% and 20% greater for AP (1.5 ng/mg) and MA (3.0 ng/mg), respectively. In short, the hybridSPE technique was shown to minimize the matrix effects, improving GC-MS analysis of hair. Based on the results, the proposed method proved to be effective for the selective determination of MA and AP in hair samples.
样品制备是从复杂基质中分离目标化合物进行可靠和准确分析的重要步骤。头发样品通常在提取前根据喜好进行研磨或精细切割，提取方法包括固相萃取（SPE）、液液萃取和其他方法。在这项研究中，开发并验证了一种基于混合固相萃取（hybridSPE）和气相色谱-质谱联用（GC-MS）的方法，用于测定头发中的甲基苯丙胺（MA）和苯丙胺（AP）。头发样品在用去离子水和丙酮洗涤后进行机械研磨。然后将样品在甲醇中于 50°C 下超声处理 1 小时，并在 50,000×g 下离心 3 分钟。上清液转移到 hybridSPE 小柱上，并用 1 mL 0.05 M 甲醇盐酸进行提取。合并溶液蒸发至干，用五氟丙酰酐衍生化，并用 GC-MS 分析。AP 的线性范围为 0.05-5.0 ng/mg，MA 的线性范围为 0.1-10.0 ng/mg，线性相关系数均大于 0.9998。AP 的回收率为 83.4-96.8%，MA 的回收率为 83.4-96.8%。日内和日间准确度分别为-9.4%至 5.5%和-5.1%至 3.1%，日内和日间精密度均在 8.3%和 6.7%以内。AP 的检出限为 0.016 ng/mg，MA 的检出限为 0.031 ng/mg。验证后的 hybridSPE 方法用于 MA 和 AP 的提取，与我们实验室目前使用的甲醇提取方法进行了比较。结果表明，对于低浓度质控（QC）样品，额外的 hybridSPE 步骤可提高回收率 5.7%，对于高浓度 QC 样品，可提高回收率 24.1%。此外，将 hybridSPE 方法与聚合型反相 SPE 方法进行了比较，对于 hybridSPE，AP（1.5 ng/mg）和 MA（3.0 ng/mg）的绝对回收率分别提高了 50%和 20%。总之，hybridSPE 技术可最大程度地减少基质效应，改善头发的 GC-MS 分析。基于这些结果，该方法可有效用于头发样品中 MA 和 AP 的选择性测定。
