Publication: Voltammetric detection and quantification of lead and cadmium in traditional herbal medicines using screen-printed electrodes
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Date
2026-02
Authors
Thangapandian, Mivilaays
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Abstract
Traditional herbal medicines (THMs) are widely used as complementary healthcare products because of their natural origin and easy accessibility, yet serious safety concerns remain due to possible contamination with toxic heavy metals such as lead (Pb) and cadmium (Cd). In this study, a simple, low-cost, and portable electrochemical method for the simultaneous detection and quantification of Pb and Cd in traditional herbal medicines was developed using differential pulse anodic stripping voltammetry (DPASV) with bare screen-printed carbon electrodes (SPEs). Herbal samples were subjected to microwave-assisted acid digestion, followed by electrochemical analysis in acetate buffer (pH 4.5) using a portable potentiostat. A screening method using cyclic voltammetry was first used to identify the potential range of Pb and Cd; method validation was then performed in accordance with AOAC guidelines by evaluating linearity, limits of detection, repeatability, and reproducibility. The method demonstrated good linearity for Pb (1–10 mg/L, R² = 0.9938) and Cd (5–30 mg/L, R² = 0.992), with limits of detection of 0.94 mg/L and 3.75 mg/L, respectively. Precision studies showed acceptable repeatability and reproducibility. Analysis of ten commercially available herbal medicine samples revealed that nine samples contained no detectable Pb or Cd within the method’s detection limits. One sample, Tongkat Ali (Eurycoma longifolia), exhibited detectable Cd at 2.47 mg/L, while Pb was not detected in any sample. In conclusion, the developed DPASV using SPEs provides a reliable and practical approach for screening heavy metal contamination in traditional herbal medicines.
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