Analyte Recovery of Volatile Organic Compounds: A Passive Sampling Analysis via Photothermal Desorption Compatible...

Area of Science:

• Industrial Hygiene
• Analytical Chemistry
• Materials Science

Background:

• Occupational exposure to volatile organic compounds (VOCs) is prevalent across industries, necessitating effective compliance sampling methods.
• Existing VOC exposure assessment methods face limitations in analytical sensitivity and time-to-knowledge.
• Photothermal desorption (PTD) is a novel pre-analytical technique developed to enhance VOC analysis by using light pulses to desorb analytes from carbonaceous sorbents.

Purpose of the Study:

• To determine the percent mass recovery of specific VOCs (toluene, n-hexane, isopropyl alcohol, trichloroethylene) using the PTD technique.
• To quantify the analyte adsorption capacities of buckypaper (BP) sorbents for these target VOCs.
• To characterize the performance of a prototype PTD-compatible diffusive sampler for potential in-field deployment.

Main Methods:

• Developed a first-generation PTD-compatible diffusive sampler prototype.
• Collected samples of toluene, n-hexane, isopropyl alcohol, and trichloroethylene.
• Quantified percent mass recovery per PTD pulse and determined analyte adsorption capacities of buckypaper sorbents.

Main Results:

• Percent mass recovery per PTD pulse varied among VOCs: toluene (0.60 ± 0.09%), n-hexane (1.2 ± 0.09%), trichloroethylene (1.1 ± 0.1%), and isopropyl alcohol (14.0 ± 1.0%).
• Analyte adsorption capacities for BP sorbents were determined: toluene (152 ± 5 mg/g), n-hexane (75 ± 42 mg/g), trichloroethylene (104 ± 37 mg/g), and isopropyl alcohol (105 ± 19 mg/g).
• Observed differences in desorption are attributed to intermolecular forces, while variations in adsorption capacity may stem from sorbent nonuniformity.

Conclusions:

• The PTD technique, when used with passive air samplers, demonstrates significant potential for improving VOC exposure assessment.
• Initial characterization data provides a foundation for further development of PTD and associated sampling devices.
• Further research is needed to refine the prototype sampler for reliable in-field industrial hygiene applications.