Differentiation of Cotton Fabrics Using Stable Isotope Ratio Mass Spectrometry

White cotton fibers are of special importance in forensics due to bleached cotton's ubiquity in the clothing industry. While these fibers are often difficult to distinguish using conventional chemical techniques, stable isotope ratio mass spectrometry has proven a useful tool for their analysis. Our goal was to investigate the potential for applying this technique to the differentiation of t-shirts and other cotton products. Analysis was performed using an elemental analyzer, a high-temperature conversion/elemental analyzer, and a continuous flow isotope ratio mass spectrometer. Cotton samples of various manufacturing origins were analyzed to investigate the homogeneity and differentiability of the samples. Additionally, fibers of samples originating from the same source were studied. Differences between sewing thread and cloth in clothing samples were also analyzed. Differentiability was determined using ANOVA tests, and visualization was achieved using three-dimensional trivariate plot analysis. Each individual cotton sample was found to be largely homogeneous, but samples from different sources were distinguishable. Sewing thread and cloth fibers were also found to be differentiable. Based on this pilot study, stable isotope ratio mass spectrometry shows promise as a tool for the analysis of cotton fibers, especially when multiple isotopes are used to discriminate between samples.