Detection of common drug metabolites in urine using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR)

Abstract

This study seeks to establish a rapid, non-invasive methodology for the detection of drug abuse through the identification of common urinary drug metabolites utilizing attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). ATR-FTIR spectroscopy was employed to detect and differentiate metabolites of heroin (6-AM), ecstasy (MDA), and cocaine (BE) in urine samples across a range of concentrations. Advanced chemometric approaches, encompassing principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), and orthogonal partial least squares discriminant analysis (OPLS-DA), were applied to construct robust discriminative models. Spectral data from both the fingerprint region and the full spectral range were analyzed to maximize analytical precision. The proposed ATR-FTIR method demonstrated remarkable sensitivity, achieving detection of drug metabolites in urine at concentrations as low as 0.02 mg/mL without necessitating sample separation or extraction steps. The OPLS-DA model exhibited superior discriminative performance, effectively distinguishing all three metabolites in both calibration and validation sets. These findings underscore the potential of integrating ATR-FTIR with chemometrics for the development of a rapid and reliable drug screening tool. This pilot investigation demonstrates that the integration of ATR-FTIR spectroscopy with chemometric analysis represents a highly promising strategy for the detection of urinary drug metabolites, circumventing the need for complex sample pretreatment procedures. This approach offers a novel, efficient, and non-invasive solution for the rapid identification of drug abuse, with substantial implications for forensic medicine and public health surveillance.