Direct Analysis in Real Time Ionization Source coupled with Mass Spectrometry (TD-DART-MS) has been used to identify the polymeric backbone structures of different textile materials such as cotton, nylon, polyester, cellulose triacetate, poly(propylene) and poly(acrylonitrile) in our lab. This analysis is very important to forensic trace analysis as examiners should perform a combination of methods to characterize fiber evidence, along with providing a complete and specific description of an item, rigorously assessing its uniqueness, and value as evidence. While methods such as Liquid chromatography-mass spectrometry (LC-MS) are currently applied, it can be laborious and time-consuming (e.g., about 1 hour). This study will propose and evaluate the unique TD-DART-MS method for the analysis of specifically dyes on differing fibers, which differs from past studies on fibers using TD-DART-MS. There are thousands of textile dyes which are often classified into different categories according to their application method and their chemical composition. This study will focus on the blue dyes from four categories including acid, basic, reactive, and vat blues which are commonly used in manufactured textiles and are more likely to have forensic value. Dye standards will be analyzed through TD-DART-MS and the characteristic ions will be identified. Fabric sheets, each dyed with an individual blue dye, will also be analyzed and compared to the standard and the method will be compared and validated by a standard Raman microscopic method. The expected results will show characteristic ions in the dyed fiber spectra that are consistent with the dye standards. The information collected will be useful to the study of fiber evidence in forensic science as the TD-DART-MS is not only a faster method, but can be a stand-alone method to provide a multidimensional chemical profile of textile fiber evidence.
