Molecularly imprinted polymer solid-phase extraction of synthetic cathinones from urine and whole blood samples

Abstract

In forensic drug analysis, extractive pretreatment is required prior to instrumental analysis to ensure successful detection of the target compounds. However, conventional extraction methods such as hydrophilic polymer-based solid-phase extraction and liquid-liquid extraction are unsuitable for an emerging class of new psychoactive substances, namely, synthetic cathinones, because they exhibit a lack of class selectivity and increased risk of target analyte decomposition during extraction. To address these issues, we describe a highly class-selective sample clean-up method for the extraction of synthetic cathinones from urine and whole blood samples, exploiting a molecularly imprinted polymer solid-phase extraction cartridge. In terms of the influence of the synthetic cathinone molecular structure on the extraction recovery, we showed that while longer alkyl side chains slightly reduced the extraction efficiency, substituent variation on the aromatic ring exerted no effect. Molecularly imprinted polymer solid-phase extraction of 11 synthetic cathinones from urine samples yielded higher recoveries than the two conventional extraction methods, and smaller matrix effect was observed than that with hydrophilic polymer-based solid-phase extraction. Molecularly imprinted polymer solid-phase extraction from whole blood samples gave recoveries comparable to those of urine samples. Therefore, the proposed method is applicable for the extraction and quantitative determination of synthetic cathinones in biological samples.

Keywords: molecularly imprinted polymers; solid-phase extraction; synthetic cathinones; urine; whole blood.