Determination of Cadmium in Different Groundwater Samples by ComplexometricPrinciple and Atomic Absorption Spectroscopy: A ComparativeStudy

Introduction: Heavy metal contamination, particularly with cadmium (Cd²⁺), poses a serious threat to environmental and human health. Conventional methods such as atomic absorption spectroscopy (AAS) are reliable but require costly equipment and skilled personnel. To address the need for rapid, cost-effective, and portable analysis, a novel microfluidic cloth-based analytical device (μCAD) has been developed based on the simple complexometric principle, facilitating on-site detection of cadmium in water samples. Materials and Methods: The μCAD was fabricated using cotton fabric through a wax-dipping method to create hydrophobic barriers. The treated fabric was then impregnated with a mixture of EDTA, lead nitrate, citric acid, and finally xylenol orange as an indicator. The system was optimized to maintain a pH of 10 to enhance colour intensity. Upon loading aqueous samples containing cadmium, the interaction between analytes and reagents resulted in a reddish-brown colour formation. The colour intensity was directly proportional to the cadmium concentration. Image analysis was performed using ImageJ software to quantify the analyte concentration, based on pre-calibrated colour scales. Results: The μCAD demonstrated effective detection of cadmium within a working range of 20–60 ppm. The limit of detection (LoD) and limit of quantification (LoQ) were determined to be 3.84 ppm and 11.60 ppm, respectively. The method was successfully applied to the analysis of real groundwater samples from the nearby region. The results obtained were in good agreement with those measured by atomic absorption spectroscopy, confirming the device’s reliability. Discussion: The use of the complexometric principle in a μCAD platform enabled a fast, reliable, and easy-to-interpret detection method for cadmium. The reddish-brown colour intensity served as a direct visual and quantifiable indicator of Cd²⁺ concentration. Compared to traditional AAS, the μCAD provided a portable, low-cost alternative suitable for field analysis, requiring minimal technical expertise. Conclusion: A novel μCAD-based method was developed and validated for the detection of cadmium in water samples. The device demonstrated good sensitivity, reproducibility, and agreement with standard AAS results. Its simplicity, portability, and rapid response make it a promising tool for environmental monitoring of cadmium-contaminated water sources.