Perchlorate sensing—Can electrochemistry meet the sensitivity of standard methods?

• Perchlorates in environment rise concerns, sensitive determination techniques needed. • Analysis and critical evaluation of published electrochemical perchlorate sensors. • Voltammetric methods superior over „classical" potentiometric ISE. • Electrochemical impedance and capacitance sensors - the lowest detection limit. • Capability of electrochemical sensors to replace ion/mass chromatography shown. Growing concerns about adverse effects of perchlorate (ClO 4 −) together with its relatively frequent occurrence in the environment demand sensitive analytical methods. It is also anticipated that ClO 4 − sensors will find their application in future extra-terrestrial missions. Ion chromatography (IC) and mass spectroscopy (MS) provide sufficiently low detection limit (LOD) but lack transportability and field analysis possibility that are provided by most electrochemical analytical methods. On the other side, commercially available potentiometric ion-selective electrodes (ISEs) cannot compete with IC or MS in terms of sensitivity. To answer the question whether (and how) such drawback can be overcome, in this paper electrochemical methods of ClO 4 − determination are introduced and evaluated. Starting with potentiometric ISEs which can theoretically reach LOD suitable for assessment of WHO-set limits of ClO 4 −, it is further shown that ISEs operating in voltammetric mode are superior in terms of sensitivity. Next section covers impedimetric and capacitance ClO 4 − sensors, concluding that they can reach detection limits of IC or MS while retaining their advantages. In further sections related issues are discussed including biosensing or direct electrochemical reduction of perchlorate as well as diversity of (nano)materials applicable for perchlorate sensors preparation. This critical review thus shows that electrochemical ClO 4 − sensors can reach sensitivity of standard methods while retaining their portability and ease of operation. [ABSTRACT FROM AUTHOR]