Analysis and electroanalysis of perchlorate in water and food samples: a critical review

Perchlorate, ClO₄⁻, with diverse applications, has become one of the major contaminants in surface and groundwater sources. This highly soluble and stable anion poses a considerable threat to human health given that it contaminates drinking water, vegetables, milk, and other contaminated food products. ClO₄⁻ can impair the thyroid function; thus, drinking water with high levels of this anion is a severe problem worldwide. However, due to the high solubility, stability, and mobility of ClO₄⁻, its remediation and monitoring remain a major challenge. Considering the various analytical methods, including electrochemistry, each method has advantages and disadvantages in terms of detection sensitivity, selectivity, analysis time, and cost. Also, sample preconcentration and clean-up must be performed for the analysis of more complex matrices such as food and biological samples to ensure a low detection limit and selectivity. Both ion chromatography (IC) and capillary electrophoresis (CE) coupled with electrochemical detection, in addition to liquid chromatography (LC)-mass spectrometry (MS), are expected to play key roles due to their lower detection limit with excellent sensitivities and selectivity. Herein, we also discuss the perspective on various electrode materials for the detection of ClO₄⁻ regarding whether ClO₄⁻ can be measured at the lowest levels with the highest selectivity.