Investigation by gas chromatography-mass spectrometry of potential contamination incurred by the use of crimp-cap vial closures

Abstract

Nine types of crimp-cap vial closures were examined to determine the propensity of their septa to discharge contaminants into sample vials under a range of conditions designed to simulate those that could occur in use. Gas chromatography-mass spectrometry was used to identify the solvent-extractable components. The presence of an unpierced polytetrafluoroethylene facing reduced the degree and rate of sample contamination. Sixty components identified at significant concentrations in the solvent extracts of the vial closures were characterised. Gas chromatographic retention times, quantitative and mass spectral data are presented. Of potential importance in the field of pesticide residue analysis was the identification of ethylenethiourea and diphenylamine as possible contaminants associated with certain vial closures.