Abstract:
Disposable gloves available for sale on the New Zealand market were analysed to establish whether or not they could be differentiated. Four polymer types of disposable gloves were analysed: latex, nitrile, polyvinyl chloride (PVC) and polychloroprene. These gloves were visually compared and analysed by pyrolysis gas chromatography – mass spectrometry (Py-GCMS) and attenuated total reflection - Fourier transform infrared spectroscopy (ATR-FTIR).
Three discriminatory methods were applied to the results: comparison of physical traits, visual comparison of analytical data (chromatograms and spectra) and statistical interpretation of analytical data by principal component analysis (PCA) and sparse partial least squared linear discriminant analysis (sPLS-LDA).
Comparison of physical traits, visual comparison of analytical data and PCA individually did not achieve high levels of discrimination. However, when these methods were combined, high levels of discrimination were achieved for three polymer types. Calculated discrimination powers were 99.3% (1 d.p.) for latex gloves, 98.7% (1 d.p.) for nitrile gloves and 98.3% (1 d.p.) for PVC gloves. Polychloroprene gloves were not subjected to differentiation as only one brand was used in this study and the PCA bi-plots confirmed that there was no clustering amongst the polychloroprene analytical data. sPLS-DA was able to differentiate samples from all brands correctly, excluding polychloroprene samples.
This project has demonstrated that differentiation between different brands of disposable gloves is possible which is useful information to assist in the interpretation of forensic casework involving the comparison of disposable gloves.