A silver enhanced and sensitive strip sensor for Cadmium detection

In this study, an enhanced test strip, based on a monoclonal antibody for the cadmium-ethylenediaminetetraacetic acid (EDTA) complex, but not metal-free EDTA, has been developed. This colorimetric sensor was sensitive and specific for the detection of cadmium in aqueous samples containing excess EDTA. Through a process of silver enhancement, the visual detection limit for Cd(II) was 5 µg/L under optimised conditions and the limit of detection for semi-quantitative detection could be as low as 0.35 µg/L by using a scanning reader. The calibration curve showed that the colour intensity decreased as the Cd(II) concentration increased in the range of 0.5–5 µg/L. The other metal ions did not interfere with the determination of Cd(II). The recoveries of drinking water samples were from 98 to 108%. Consequently, the assay could be employed as a potential on-site screening tool for the detection of Cd(II) in water samples.