Portable voltammetric determination of acetaminophen using DropSens-based screen-printed carbon electrodes for...

The increasing demand for portable, low-cost, and sustainable analytical methodologies has motivated the development of miniaturized electrochemical systems for pharmaceutical and clinical monitoring. In this work, an electrochemical method based on screen-printed carbon electrodes and nickel oxide-modified SPCE was optimized for the voltammetric determination of acetaminophen in pharmaceutical formulations and human urine using the DropSens configuration. Square-wave voltammetry, selected for its sensitivity and suitability for on-site analysis, enabled reliable quantification under alkaline conditions (pH 9.5). Both electrode types provided detection limits in the low-ppm range and broad linearity. Precision values varied depending on the matrix and electrode type, with RSDs generally below 20%. Accuracy ranged from 87 to 108% in drug formulations and exceeded 90% in urine samples. The DropSens platform produced analytical results comparable to those obtained with a conventional electrochemical cell while reducing sample and reagent consumption. Method validation for urine analysis was performed using in-tube solid-phase microextraction coupled to nano liquid chromatography with diode-array detection, which confirmed the reliability of the voltammetric method. Excretion profiles obtained by the proposed electrodes closely matched chromatographic data, with differences below 1% at the main excretion maxima (2 and 6 h after administration). Overall, the proposed miniaturized electrochemical approach provides a rapid, accurate, and sustainable alternative for the determination of acetaminophen in complex biological matrices, offering significant advantages in terms of portability, operational simplicity, and alignment with green analytical chemistry principles. The HEXAGON tool was used to support this last statement.