Ready-to-deploy electrochemical sensor for enhanced detection sensitivity of water-insoluble Compounds: Application...

The detection of water-insoluble compounds is crucial across scientific, pharmaceutical, and environmental fields. Due to their poor aqueous solubility, water-insoluble compounds pose analytical challenges, necessitating specialized detection methods. Gel electrolytes have emerged as promising platforms for portable electrochemical detection by reducing solvent usage, minimizing sample consumption, and simplifying handling procedures. However, their limited swelling in organic solvents significantly hinders their effectiveness in detecting these poorly soluble targets. Addressing this limitation by enhancing the compatibility of gel electrolytes with non-aqueous environments not only broadens their usability but also enables substantial improvement in detection sensitivity, particularly for lipophilic pharmaceutical compounds. (98).

We present a novel ready-to-deploy electrochemical sensor for the sensitive detection of water-insoluble compounds, utilizing a gelatin-based gel electrolyte integrated with a MoS₂-modified screen-printed carbon electrode (MoS₂-SPCE). The gelatin gel, cross-linked with boric acid and plasticized with lactic acid, facilitates efficient electron transfer and enhances sensitivity. Analytical performance was demonstrated via the detection of retinoic acid (RA), a hydrophobic pharmaceutical compound, using differential pulse voltammetry (DPV). The sensor demonstrated a wide linear range (50.0 μM-1.00 mM) with a LoD of 9.77 μM, excellent reproducibility (RSD = 3.66 %), and stable performance over seven weeks. Remarkably, compared to a conventional liquid electrolyte, the proposed platform achieved a 4.25-fold enhancement in detection sensitivity. Furthermore, successful application to commercial pharmaceutical formulations yielded acceptable recovery, consistent with labeled content. These results highlight the potential of the ready-to-deploy sensor as a practical, field-deployable electrochemical sensing platform for the enhanced detection of hydrophobic analytes. (149).

This study represents the first instance of employing a ready-to-deploy gel electrolyte system that significantly enhances sensitivity toward water-insoluble analytes. It addresses a critical challenge in current sensor technologies by enabling significantly enhanced sensitivity, simplified operation, and elimination of solvent leakage. The proposed ready-to-deploy sensor establishes a new benchmark for portable electrochemical systems, which not only fills a critical gap in sensor technology but also opens new avenues for field-deployable, high-performance detection of hydrophobic analytes in pharmaceutical, environmental, and biomedical applications. (81).