This paper describes the development and evaluation of a nontargeted electrochemical surface-enhanced Raman spectroscopy (EC-SERS) screening method applied to forensic seized drug casework samples.
This study discusses the development and evaluation of electrochemical surface-enhanced Raman spectroscopy (EC-SERS) screening applied to forensic seized drug casework samples, a novel workflow that can be applied both in the laboratory and on-site as a fast, inexpensive, and selective approach to seized drug screening. EC-SERS provided an accurate screening result of 86 % using the 1st derivative correlation. Applying knowledge of both the local drug landscape and the prevalence of specific adulterants, this value improved to a positive screening of 93 % for the authentic samples. Using cyclic voltammetry and a 785 nm Raman spectrometer, a nontargeted screen was developed using silver screen-printed electrodes and tested on a panel of common drugs of abuse and adulterants. Following characterization of the analyte panel, in-house binary and tertiary mixtures were assessed and the effectiveness of the developed EC-SERS method was tested using common score-based algorithms including correlation, hit-quality-index, spectral angle mapper, and correlation of the 1st derivative. For in-house blind samples, this approach allowed for positive identification of at least one compound in 100 % of samples.