Effects of polar and non-polar gun-cleaning solvent components on permeation characteristics of two major organic gunshot residues through disposable nitrile gloves.

Abstract

While the hazards posed by lead in gunshot residues (GSRs) are recognized, little is known about the glove permeation of the organic components. The permeation behavior of the major organic GSRs methyl centralite and ethyl centralite through disposable nitrile glove material was investigated. The compounds were contained in three solvents: Hoppe's no. 9 gun cleaning solvent (GCS), n-decane, and a GCS surrogate, n-decane/ethanol 7:3 (w/w) mixture. The aim was to identify whether ethanol was the key driver of a previously reported carrier effect. A modified ASTM F739-20 method was used for permeation testing at 35.0 ± 0.5 °C with closed-loop n-decane collection solvent without recirculation. Gas chromatography-mass spectrometry analysis facilitated GSR quantification. Significant differences occurred in intrarun but not interrun glove physical characteristics and in analyte permeation for the GCS and its surrogate. The GCS caused a substantial increase in permeation rate before a lower steady state permeation rate (SSPR). In contrast, n-decane/ethanol produced its SSPRs as the maximum permeation rate, but with decreased permeation rates and total permeated analyte mass. n-Decane solvent caused none of the GSR to enter the steady state and exhibited much longer breakthrough times. This study underscores the importance of considering the complete chemical composition of mixtures in assessing their interactions with glove personal protective equipment (PPE) and highlights the need for comprehensive testing protocols in PPE selection. Limitations included the lack of previous research on organic GSR glove permeation and challenges in comparing study results with manufacturer-reported glove resistance data. Adjusted concentrations for analytes and stepwise reconstitution of GCS components are recommended for future investigations. The present research provided insight into the glove permeation behavior of complex chemical mixtures for better glove PPE selection and testing practices.