Studying the effect of cocaine on the structure of cosmetically treated human hair using micro-Attenuated Total Reflection spectroscopy (ATR)

Abstract

It has been demonstrated that hair can accumulate and trap drugs over time with exposure and use, thus being able to provide a useful indication of long-term exposure. Studying changes in the structural components of hair, which may occur as a result of drug binding processes, can be a useful tool in understanding the issues involving false positive results from hair drug testing. Furthermore, the effect of cosmetic treatments, such as bleaching and straightening on hair structural changes, may help to understand the effect of drugs on human hair structure with pre-treatment history. In this investigation, changes resulting from exposure of bleached, unbleached, and straightened, neat blonde Caucasian hair to external cocaine were examined. Cocaine was chosen as the test drug as it is among the most widely abused substances. The results from infrared spectra and their second derivatives with aid of multivariate statistical method, PCA analysis demonstrated that changes in the hair structure occurred as a result of these treatments.