Thermal desorption gas chromatography-mass spectrometric analysis of polycyclic aromatic hydrocarbons in atmospheric fine particulate matter

Thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) is used to analyze polycyclic aromatic hydrocarbons (PAHs) in atmospheric fine particulate matter. However, despite the high sensitivity of TD-GC-MS, the recovery rate of PAHs is greatly influenced by active sites in the equipment. PAHs are decomposed or adsorbed at active sites, decreasing quantitative accuracy. Also, the thermal extraction of PAHs is easily affected by the matrix in PM2.5 samples, decreasing the thermal extraction efficiency. Herein, the analytical sensitivities of PAHs were improved by adding analyte protectant (AP) and thermal desorption aid (TDA) as an auxiliary agent. The combination of 2 mu 1. of 0.5 w/v% D-sorbitol (as AP) and 2 mu 1. of 10 w/v% Tween (R) 20 (as TDA) was found to be most effective in improving the analytical sensitivity of PAHs. The sensitivities of 5-6-ring PAHs with high boiling points increased most when analyzing blank filter papers added with PAHs standard sample or real samples of PM2.5 compared with the samples without the auxiliary agent. When analyzing real samples of PM2.5, the peak areas of 5-ring and 6-ring PAHs in the PM2.5 sample added with the optimized auxiliary agent were 1.40 and 1.96 times that without the auxiliary agent. It is considered that AP in the auxiliary agent covered active sites and protected PAHs undergoing decomposition or adsorption. TDA improved the thermal extraction rate of high boiling point PAHs. When using alternative heat sampling equipment to analyze low concentrations of high boiling point components, the auxiliary agent proposed herein can increase the analytical sensitivity toward the target compounds. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study enhanced the analytical sensitivities of PAHs by adding analyte protectant and thermal desorption aid as auxiliary agents, which covered active sites and improved the thermal extraction rate. When analyzing real PM2.5 samples, the peak areas of 5-ring and 6-ring PAHs with the optimized auxiliary agent were 1.40 and 1.96 times higher than those without the auxiliary agent.