3, 3′-Diaminobenzidine with dual o-phenylenediamine groups: two in one enables visual colorimetric detection of nitric oxide

摘要

titleAbstract/titlepNitric oxide (NO) plays an important role in the generation of smog and ozone. Although great efforts have been made to determine NO by using o-phenylenediamine (OPD)-based fluorescent probes, more simple and reliable colorimetric assays for detection of NO are extremely scarce because a single OPD structure cannot produce enough optical absorption for chromogenesis. In this study, we report an innovative two-in-one visual colorimetric methodology. Commercially available 3,3′-diaminobenzidine (DAB) with two OPD structures in a single molecule is selected as the colorimetric probe, and it reacts with NO via diazo-coupling reaction to generate 1H,3’H-5,5′bibenzotriazolyl because of the increase of conjugated double bonds, accompanying a distinct color change from colorless to brownish yellow. This two-in-one colorimetric assay can determine NO at a concentration as low as 3?ppm by the naked eye and 40?ppb by UV-vis spectrometry, which is the lowest limit of detection (LOD) among reported colorimetric assays for NO. Moreover, the present two-in-one visual colorimetric assay also has good selectivity toward NO over other common potential gas interferents such as COsub2/sub, NOsub2/sub, NHsub3/sub, Nsub2/sub, Osub2/sub, and SOsub2/sub. This present study provides a new insight for the design and development of assays for NO./ppfigcaptionpGraphical abstract/p/captiongraphic/graphic/fig/p