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Vacuum‐assisted headspace solid‐phase microextraction (Vac‐HS‐SPME) is a technique used to enhance SPME sampling of semi‐volatile organic compounds. Here, it was combined with a high‐capacity SPME Arrow, which features a larger volume of extraction phase and a more rugged configuration than traditional extraction fibers. An in‐depth assessment of the critical parameters was conducted to achieve optimal extraction of representative compounds from a model solid sample matrix (Ottawa sand). Operational fundamentals investigated included the types of seals needed to create a leak‐free environment under vacuum conditions; the magnitude of the vacuum applied and time needed to activate the Vac kinetics; order of sample vial preparation methods (VPMs); and other standard variables associated with extract analysis by gas chromatography‐mass spectrometry. When exploring the limits of sample VPMs, results indicated an ideal workflow requires the solid sample to be spiked before sealing the vial, allow the sample to rest overnight, then apply vacuum at a pressure of ‐677 mbar (out of ‐789 mbar maximum possible vacuum with pump and compressor used), exerted on the vial for 90 s. This work provides the necessary workflow for the optimization of Vac‐HS‐SPME sampling of analytes from solid matrices. [ABSTRACT FROM AUTHOR]

Despite the growing popularity of electronic cigarettes, relatively little work has been done to characterize their aerosols. In this study, we developed a quick, simple device for sampling electronic cigarette aerosol onto thermal desorption tubes. This novel sampling approach--paired with an Rtx®-VMS column and GC-MS analysis--provides detectable levels of volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs) from a single 40 mL puff., Most electronic cigarette (e-cigarette) research to date has focused on the composition of the e-cigarette liquid; however, users ultimately are exposed to the aerosol. Only a few researchers (e.g., Goniewicz [...]

Abstract: A thermal extraction-gas chromatography-mass spectrometry (TE-GC-MS) method was utilized to quantitatively examine semivolatile organic compounds (SVOCs) in fine particulate matter (PM2.5) collected from light-duty, gasoline-powered vehicle (LDGV) exhaust. Emissions were analyzed from a subset of 18 vehicles tested in the Kansas City Light-Duty Vehicle Emissions Study (KCVES). The KCVES applied the LA92 Unified Driving Cycle (UDC), consisting of “cold start”, “hot stabilized running”, and “warm start” phases. The sensitivity of the TE-GC-MS analysis provided the opportunity to examine the emission rates and proportions of SVOCs (including polycyclic aromatic hydrocarbons (PAHs), hopanes, and steranes) in PM2.5 on an individual vehicle basis for each UDC phase. Mean target SVOC emissions rates of 5.01μgkm−1, 0.28μgkm−1, and 0.63μgkm−1 were reported for the cold start, hot stabilized running, and warm start phases, respectively. Operating conditions as depicted by each UDC phase significantly affected SVOC emission rates and proportions in PM2.5. The cold start phase emission rates were significantly higher than the hot stabilized running and warm start phases for 89% of the target SVOCs. An increase in SVOC proportions in PM2.5 was observed during the warm start phase compared with the cold start and hot stabilized running phase. This observation was significant for 31% of the target compounds, including chrysene, benzo[a]anthracene, and pyrene. Vehicles tested in both summer and winter provided emissions data describing ambient temperature effects. Emission rates were significantly higher in the winter for 92% of the target SVOCs. Until now, observations of specific SVOCs in motor vehicle emissions produced under changing operating conditions were scant. Such emissions data may be useful for emissions modeling, source apportionment studies, and human exposure assessments. [Copyright &y& Elsevier]

Airborne aldehyde and ketone (carbonyl) sampling methodologies based on derivatization with 2,4-dinitrophenylhydrazine (DNPH)-coated solid sorbents could unequivocally be considered the "gold" standard. Originally developed in the late 1970s, these methods have been extensively evaluated and developed up to the present day. However, these methods have been inadequately evaluated for the long-term (i.e., 24 h or greater) sampling collection efficiency (CE) of carbonyls other than formaldehyde. The current body of literature fails to demonstrate that DNPH-coated solid sorbent sampling methods have acceptable CEs for the long-term sampling of carbonyls other than formaldehyde. Despite this, such methods are widely used to report the concentrations of multiple carbonyls from long-term sampling, assuming ~100% CEs. Laboratory experiments were conducted in this study to evaluate the long-term formaldehyde and acetaldehyde sampling CEs for several commonly used DNPH-coated solid sorbents. Results from sampling known concentrations of formaldehyde and acetaldehyde generated in a dynamic atmosphere generation system demonstrate that the 24-hour formaldehyde sampling CEs ranged from 83 to 133%, confirming the findings made in previous studies. However, the 24-hour acetaldehyde sampling CEs ranged from 1 to 62%. Attempts to increase the acetaldehyde CEs by adding acid to the samples post sampling were unsuccessful. These results indicate that assuming ~100% CEs for 24-hour acetaldehyde sampling, as commonly done with DNPH-coated solid sorbent methods, would substantially under estimate acetaldehyde concentrations. [ABSTRACT FROM AUTHOR]