PLOT-cryoadsorption concentrates headspace vapors by sweeping them through porous layer open tubular (PLOT) capillaries chilled to 0 °C to promote adsorption onto an alumina layer. Compared to passive headspace concentration employing activated charcoal strips (ACSs) as adsorbents, PLOT-cryoadsorption has several potential advantages for extracting ignitable liquid (IL) residue from fire debris evidence. Capillary vapor traps can be monitored for breakthrough to avoid problematic displacement that occurs when an adsorbent becomes saturated. Capillaries can also be eluted with acetone to avoid highly toxic carbon disulfide. Future adoption of PLOT-cryoadsorption for fire debris analysis requires investigation of sampling parameters including collection volume, flow rate, and temperature. Here we employ a simple five-component surrogate for diesel fuel (that is, a simulated or artificial diesel fuel) to study the effect of flow rate and sample temperature on the composition and spatial distribution of the collected headspace. Flow rates at or below 1.5 scc (standard cubic centimeters)/min yielded the most repeatable results. Across the range 60 °C to 120 °C, we found that high sample temperatures allowed for the collection of more total sample and shifted its composition towards lower-volatility components. Consistent with chromatographic theory, higher-volatility components traveled furthest along the length of the capillary and were more prone to breakthrough. We conclude that the surrogate mixture allowed for effective, quantitative comparisons between sampling conditions that could be translated to real diesel fuel.

PLOT低温吸附通过将顶空蒸气扫过冷至0°C的多孔层开放式管状（PLOT）毛细管来浓缩顶空蒸气，从而促进吸附到氧化铝层上。与使用活性炭条（ACS）作为吸附剂的被动顶空浓缩相比，PLOT低温吸附具有从火屑证据中提取可燃液体（IL）残留物的几个潜在优势。可以监测毛细管疏水器的穿透情况，以避免吸附剂饱和时发生有问题的置换。毛细管也可以用丙酮洗脱，以避免剧毒的二硫化碳。未来采用PLOT低温吸附进行火屑分析需要调查采样参数，包括收集量，流量和温度。在这里，我们采用一种简单的五组分替代柴油燃料（即模拟或人造柴油燃料）来研究流速和样品温度对所收集顶空的组成和空间分布的影响。1.5 scc（标准立方厘米）/分钟或以下的流速产生了最可重复的结果。在60°C至120°C的温度范围内，我们发现较高的样品温度可收集更多的总样品，并将其组成移向挥发性较低的组分。与色谱理论一致，较高挥发性的组分沿毛细管的长度移动最远，更易于突破。我们得出的结论是，替代混合物可以在可以转换为实际柴油的采样条件之间进行有效的定量比较。模拟或人工柴油燃料）以研究流速和样品温度对所收集顶空的组成和空间分布的影响。1.5 scc（标准立方厘米）/分钟或以下的流速产生了最可重复的结果。在60°C至120°C的温度范围内，我们发现较高的样品温度可收集更多的总样品，并将其组成移向挥发性较低的组分。与色谱理论一致，较高挥发性的组分沿毛细管的长度移动最远，更易于突破。我们得出的结论是，替代混合物可以在可以转换为实际柴油的采样条件之间进行有效的定量比较。模拟或人工柴油燃料）以研究流速和样品温度对所收集顶空的组成和空间分布的影响。1.5 scc（标准立方厘米）/分钟或以下的流速产生了最可重复的结果。在60°C至120°C的温度范围内，我们发现较高的样品温度可收集更多的总样品，并将其组成移向挥发性较低的组分。与色谱理论一致，较高挥发性的组分沿毛细管的长度移动最远，更易于突破。我们得出的结论是，替代混合物可以在可以转化为实际柴油的采样条件之间进行有效的定量比较。