Kim Ki-Hyun
Atmospheric Environment Laboratory, Department of Earth & Environmental Sciences, Sejong University, Seoul, Korea.
Environ Monit Assess. 2006 Dec;123(1-3):259-69. doi: 10.1007/s10661-006-9195-8. Epub 2006 Jun 16.
In this work, the basic properties of the bag sampling method were examined and characterized in terms of recovery rate with respect to four reduced sulfur compounds (RSC) including H2S, CH3SH, DMS, and DMDS. For this comparative study, two types of calibration approaches were performed to evaluate the relative RSC loss due to bag sampling. As a reference calibration tool, a syringe dilution (SD) method was applied. The working standards prepared by diluting the primary standard in a gas-tight syringe (as a mixing chamber) were injected to the GC/PFPD through a loop-injection system to yield a background calibration information. In contrast, the target calibration was performed based on a bag dilution (BD) method. To this end, working standards for multiple calibration points were prepared by two different bag types (Tedlar bag (TB) and polyester bag (PB)). These standards were then drawn by the same syringe and injected into the GC/PFPD via loop. On the basis of these comparative analyses, both absolute and relative differences in RSC recovery rates (RR) were evaluated (e.g., comparison of wall-loss effect). The results indicate that TB has a mean RR of 87% for the four RSC with their values ranging from 82 (CH3SH) to 91% (DMDS). On the other hand, the results of PB generally exhibited slightly reduced RR with their mean values of 77% (range: 73% of H2S to 83% of DMS). The results of this study generally suggest that the losses of RSC samples, while inevitable with the bag sampling method, exhibit certain patterns between different RSCs and between different grab sampling materials.
在本研究中，考察并表征了气袋采样法的基本特性，具体是针对包括硫化氢（H₂S）、甲硫醇（CH₃SH）、二甲基硫醚（DMS）和二甲基二硫醚（DMDS）在内的四种还原性硫化合物（RSC）的回收率。对于这项对比研究，采用了两种校准方法来评估气袋采样导致的相对RSC损失。作为参考校准工具，应用了注射器稀释（SD）法。将通过在气密注射器（作为混合室）中稀释一级标准物质制备的工作标准液，通过定量环进样系统注入气相色谱/脉冲火焰光度检测器（GC/PFPD），以获取背景校准信息。相比之下，目标校准是基于气袋稀释（BD）法进行的。为此，使用两种不同类型的气袋（泰德拉袋（TB）和聚酯袋（PB））制备了多个校准点的工作标准液。然后用同一注射器抽取这些标准液，并通过定量环注入GC/PFPD。基于这些对比分析，评估了RSC回收率（RR）的绝对差异和相对差异（例如，壁损失效应的比较）。结果表明，对于四种RSC，TB的平均RR为87%，其值范围为82%（CH₃SH）至91%（DMDS）。另一方面，PB的结果通常显示RR略有降低，其平均值为77%（范围：H₂S为73%至DMS为83%）。本研究结果总体表明，RSC样品的损失虽然在用气袋采样法时不可避免，但在不同的RSC之间以及不同的采样材料之间呈现出一定的规律。
