“…Even consolidated methods like Spectrometric (CV‐AAS, AEF, and CV‐AFS), chromatographic and potentiometric technologies, with low detection limits (LoD) of about 1 μgL −1 or 1 part per billion (ppb), and a wide linear range for arsenic detection, present some drawbacks in terms of test time, expensive reagents, the need for sample pre‐concentration, lab constraints related to bulky instrumentation, and the need for highly trained personnel (Bose et al, 2011; United States Environmental Protection Agency Office of Water, 1999; Yu & Wang, 2013). Utrasensitive method (LoD of 0.14 ppb) by colorimetric and surface‐enhanced Raman (SERS) using glutathione functionalized Au‐nanoparticles (Li et al, 2020) and rapid colorimetric assay on paper‐based microfluidic device have been described (Martinez et al, 2010; Morita & Kaneko, 2006).…”