Rapid and reliable electrochemical detection of bisphenol S in thermal paper

Bisphenol S (BPS) is a common, persistent, and mobile chemical found in everyday products such as thermal paper. BPS can easily enter the body by migrating from the paper to the fingers, disrupting the endocrine system by mimicking the oestrogen hormone, thus negatively influencing human health. Assessing BPS levels in daily life is of great importance. This study introduces a rapid and reliable approach for detecting BPS in thermal paper and tap water by developing an electrochemical analytical method. This method allows for in-situ, real-time measurements. We present a simple, low-cost electrochemical sensor for detecting BPS using screen-printed electrodes based on carbon (SPEC) and single-wall carbon-nanotube (SPE-SWCNT) working electrodes. BPS was detected over a wide linear range from 1 to 400 μM. The detection limits were 0.73 μM and 0.87 μM for the SPE-C and SPE-SWCNT electrodes, respectively. Good repeatability was observed for both sensors when using one electrode 16 times, which demonstrates its potential for real-time environmental monitoring. Additionally, traditional chromatographic methods, high-performance liquid chromatography with a diode-array detector (HPLC-DAD), and liquid chromatography-mass spectrometry triple quadrupole (LCMS), were incorporated to enhance analytical capabilities. HPLC-DAD achieved a detection limit of 3 nM after solid-phase extraction preconcentration, while LCMS triple quadrupole demonstrated a detection limit of 10 pM without preconcentration. Electrochemical screen-printed electrodes can be employed for on-site analysis and health-risk assessments in everyday settings, such as shops. However, for detecting very low concentrations where time is not a constraint, LCMS quadrupole remains the preferred technique.