A novel portable colorimetric probe for fast and selective detection of hypochlorite and its applications

Abstract A novel portable colorimetric probe TNB ( N ‐(5‐( tert ‐butyl)‐1 H ‐pyrazol‐3‐yl)‐7‐nitrobenzo[c][1,2,5]oxadiazol‐4‐amine) was developed to detect hypochlorite (ClO − ) quickly and simply. Noticeable colour changing from orange to colourless was evident in 1 s, upon the addition of ClO − into TNB. The detection limit of TNB for ClO − was 7.00 μM. TNB could reliably quantify ClO − in real water samples and a commercial bleach. The portable colorimetric probe TNB could obviously discern ClO − in varied media using paper kits. Practically, chemosensor TNB was able to quantify the amounts of ClO − with a smartphone application in environmental samples. The detection mechanism of ClO − was proposed to be hydrolytic cleavage reaction through electrospray ionisation‐mass spectrometry (ESI‐MS), proton nuclear magnetic resonance ( 1 H‐NMR) analysis, and density functional theory (DFT) calculations.