Counterterrorism and Forensic Science Research Unit, FBI Academy, Building 12, Quantico, Virginia 22135, USA.
Anal Chem. 2009 Nov 1;81(21):8724-33. doi: 10.1021/ac900565s.
A high-surface area solid phase microextraction (HSA-SPME) sampler is described for dynamic sampling at high air velocities (up to several hundred centimeters per second). The sampling device consists of a thin wire coated with carboxen/polydimethylsiloxane (carboxen/PDMS) material, wound in the annular space between two concentric glass tubes, providing a large trapping surface from which analytes may then be thermally desorbed with little power consumption upon resistive heating of the wire. Desorbed analytes are focused and reconcentrated on a microtrap that is subsequently resistively heated to introduce analytes for GC or GC/MS analysis. Benzene, toluene, ethylbenzene, and xylenes (BTEX) included in a 39-component toxic organics (TO-14) gas mixture were used to evaluate the efficiency of the HSA-SPME sampler. Quantitation of trace-level BTEX compounds present during weapons cleaning was completed using stepwise calibration. Detection limits of 0.2-6.9 pptr(v) were observed for these analytes using single ion monitoring GC/MS analysis, and an improvement in sensitivity of several orders of magnitude was achieved when compared to standard dynamic flow SPME with a commercially available 10 mm carboxen/PDMS fiber. The potential for rapid analyte uptake and improved sensitivity using the HSA-SPME design will make it possible to rapidly collect and analyze VOC samples in field settings using a portable hand-held pump and a small, low power GC/MS instrument. This system will be especially useful for situations involving forensics, public safety, and military defensive or intelligence needs where rapid, sensitive detection of airborne analytes is required.
一种高表面积固相微萃取（HSA-SPME）采样器，用于在高空气速度（高达每秒数百厘米）下进行动态采样。采样装置由涂有羧基/聚二甲基硅氧烷（carboxen/PDMS）材料的细金属丝组成，缠绕在两个同心玻璃管之间的环形空间中，提供了一个大的捕获表面，从中可以通过对金属丝进行电阻加热来进行热解吸，而消耗的功率很小。解吸的分析物被聚焦并重新浓缩到微阱上，然后通过对微阱进行电阻加热将分析物引入 GC 或 GC/MS 分析中。苯、甲苯、乙苯和二甲苯（BTEX）包含在 39 种有毒有机物（TO-14）混合气体中，用于评估 HSA-SPME 采样器的效率。使用逐步校准完成了武器清洁过程中痕量 BTEX 化合物的定量。使用单离子监测 GC/MS 分析观察到这些分析物的检测限为 0.2-6.9 pptv，与使用商业上可用的 10mm 羧基/PDMS 纤维的标准动态流量 SPME 相比，灵敏度提高了几个数量级。使用 HSA-SPME 设计快速吸收分析物和提高灵敏度的潜力将使使用便携式手持泵和小型低功率 GC/MS 仪器在现场环境中快速收集和分析 VOC 样品成为可能。该系统在涉及法医、公共安全以及军事防御或情报需求的情况下特别有用，在这些情况下需要快速、灵敏地检测空气中的分析物。
