Point-of-Care Testing of Benzene Metabolite S-Phenylmercapturic Acid Using Salt-Induced Phase Separation Combined with Nanoparticle-Based Surface-Enhanced Raman Spectroscopy

Benzene, a known toxic, carcinogenic, and pervasively present environmental pollutant, necessitates effective monitoring strategies to assess human exposure. S-Phenylmercapturic acid (S-PMA) is a specific biomarker for benzene exposure. This study presents a point-of-care testing (POCT) assay for the detection of S-PMA in human urine, integrating salt-induced phase separation (SIPS) with surface-enhanced Raman spectroscopy (SERS). S-PMA in human urine was first effectively separated using SIPS and then detected using a portable Raman spectrometer employing Au colloids as the SERS substrate. The POCT assay exhibited a clear correlation between the signal intensity and logarithmic concentration of S-PMA (0–5 ppm), demonstrating satisfactory recovery and reproducibility. Moreover, high-throughput fingerprint identification and quantitative analysis of S-PMA in urine were achieved within 10 min, with a detection limit as low as 1.06 ppb, by performing SIPS-SERS on 96-well plates. This POCT method holds promise for personal exposure assessment and may potentially aid in the prevention of benzene-induced diseases.