Integrated Aerosol Collection and Thermal-Desorption Chemical Ionization TOFMS for Rapid Particulate-Composition Analysis.

Organic molecules within particulate matter (PM) undergo oxidation by atmospheric free radicals, leading to persistent temporal fluctuations in particulate chemical composition that impose significant repercussions on human health and atmospheric visibility. Nevertheless, effective online monitoring approaches remain extremely limited. This work presents a novel integrated aerosol collection and thermal-desorption chemical ionization time-of-flight mass spectrometry (AeroCT-TOFMS) for rapid quantitative analysis of particulate alkyl organophosphate esters (alkyl-OPEs) released from packaging materials at express delivery stations (EDS). A bidirectional motion platform serves as the integrated carrier for both the aerosol collection system and the thermal-desorption system. Upon completion of sampling, the motion platform automatically transferred the membrane-loaded tray to the thermal-desorption module. The desorption of PM was accomplished via a combined heating strategy: thermal radiation from a convex copper component at 350 °C and preheated air at 110 °C. This heating protocol enabled the complete vaporization of intermediate/semivolatile organic compounds within 50 s. The system facilitated quantitative analysis of alkyl-OPEs with a linear response range of 0.1-20 ng and a limit of detection as 0.016 ng (3-fold signal-to-noise ratio). Compared to the Filter Inlet for Gases and AEROsols (FIGAERO), AeroCT achieved a 22.2 ± 2.1% increase in collection rate and up to a 204.8 ± 5.9% enhancement in triethyl phosphate (TEP) characteristic peak signals. With a single collection time of 60 min by AeroCT-TOFMS, the particle samples from EDS showed TEP concentrations of 0.43-1.61 ng/m3 and tributyl phosphate concentrations of 1.28-1.81 ng/m3, demonstrating broad application prospects for rapid quantitative particulate sample analysis.