Visiting Scientist Program, Oak Ridge Institute for Science and Education, Counterterrorism and Forensic Science Research Unit, Federal Bureau of Investigation Laboratory , Quantico, Virginia 22135, United States.
Anal Chem. 2013 Sep 17;85(18):8626-33. doi: 10.1021/ac401033a. Epub 2013 Aug 29.
This work examines a recently improved, dynamic air sampling technique, high surface area solid-phase microextraction (HSA-SPME), developed for time-critical, high-volume sampling and analysis scenarios. The previously reported HSA-SPME sampling device, which provides 10-fold greater surface area compared to commercially available SPME fibers, allowed for an increased analyte uptake per unit time relative to exhaustive sampling through a standard sorbent tube. This sampling device has been improved with the addition of a type-K thermocouple and a custom heater control circuit for direct heating, providing precise (relative standard deviation ∼1%) temperature control of the desorption process for trapped analytes. Power requirements for the HSA-SPME desorption process were 30-fold lower than those for conventional sorbent-bed-based desorption devices, an important quality for a device that could be used for field analysis. Comparisons of the HSA-SPME device when using fixed sampling times for the chemical warfare agent (CWA) surrogate compound, diisopropyl methylphosphonate (DIMP), demonstrated that the HSA-SPME device yielded a greater chromatographic response (up to 50%) relative to a sorbent-bed method. Another HSA-SPME air sampling approach, in which two devices are joined in tandem, was also evaluated for very rapid, low-level, and representative analysis when using discrete sampling times for the compounds of interest. The results indicated that subparts per billion by volume concentration levels of DIMP were detectable with short sampling times (∼15 s). Finally, the tandem HSA-SPME device was employed for the headspace sampling of a CWA degradation compound, 2-(diisopropylaminoethyl) ethyl sulfide, present on cloth material, which demonstrated the capability to detect trace amounts of a CWA degradation product that is estimated to be less volatile than sarin. The rapid and highly sensitive detection features of this device may be beneficial in decision making for law enforcement, military, and civilian emergency organizations and responders, providing critical information in a contaminated environment scenario when time is of the essence.
这项工作考察了一种最近改进的、动态的空气采样技术，即高表面积固相微萃取（HSA-SPME），该技术专为时间关键、大容量采样和分析场景而开发。与商业可用的 SPME 纤维相比，之前报道的 HSA-SPME 采样装置提供了 10 倍的更大表面积，使得在单位时间内相对于通过标准吸附管进行的彻底采样，能够增加分析物的摄取量。该采样装置通过添加 K 型热电偶和定制的加热器控制电路进行直接加热得到了改进，为被捕获的分析物的解吸过程提供了精确（相对标准偏差约为 1%）的温度控制。HSA-SPME 解吸过程的功率要求比传统的基于吸附剂床的解吸装置低 30 倍，这对于可用于现场分析的装置来说是一个重要的质量指标。当使用固定的采样时间比较化学战剂（CWA）代用化合物二异丙基甲基膦酸酯（DIMP）时，HSA-SPME 装置的比较表明，与吸附剂床方法相比，HSA-SPME 装置产生了更大的色谱响应（高达 50%）。还评估了另一种 HSA-SPME 空气采样方法，其中两个装置串联使用，当使用离散的采样时间用于感兴趣的化合物时，该方法也用于非常快速、低水平和代表性的分析。结果表明，使用短的采样时间（约 15 s）可以检测到 DIMP 的亚 ppmv 浓度水平。最后，串联的 HSA-SPME 装置用于布质材料上存在的 CWA 降解化合物 2-（二异丙基氨基乙基）乙硫醚的顶空采样，证明了检测痕量 CWA 降解产物的能力，据估计，该产物的挥发性比沙林低。该装置的快速和高灵敏度检测功能可能有助于执法、军事和民用应急组织和响应者做出决策，在时间至关重要的污染环境场景中提供关键信息。
