Electrochemical spectral methods for trace detection of heavy metals: A review

The contamination containing trace heavy metal ions (HMIs) has received great attentions, as it poses serious threats to ecological system and human health. Hence, the developments of a rapid technology for the real-time and on-line detection of HMIs are of significance. Considering the drawbacks of singular spectral method and electrochemical method, electrochemical spectral method has been proposed as a powerful analytical technology for the detection of trace HMIs because of its great sensitivity, anti-interference ability and super low limit of detection (LOD). As such, in this review, we primarily described the recent advances of representative electrochemical spectral methods and their applications, including electrochemical atomic absorption spectrometry (EC-AAS), electrochemical total reflection X-ray fluorescence and X-ray fluorescence (EC-TXRF/XRF), and electrochemical laser-induced breakdown spectroscopy (EC-LIBS). Additionally, we basically introduced the electrochemical preconcentration methods generally used prior to spectral methods, including electrodeposition and electroadsorption. Based on the overview of these methods, we also addressed up-to-date challenges of in-situ electrochemical spectral methods, for which additional researches are needed to carry out.