New turn on fluorimetric sensor for direct detection of ultra-trace ferric ions in industrial wastewater and its application by test strips

[Display omitted] •Develop fast and reliable sensing probe to monitor Fe3+ ions in waste water.•Validation of new method was achieved through comparison with established method.•Influence of some other cations has no significant effect on Fe3+ ions detection.•The sensor was displayed high sensitivity with low limit of detection.•Test strips have been successfully fabricated for fast and convenient sensing of Fe3+. New 5-(4-(dimethylamino)phenyl)-4-(2-(4-methoxy-3-methylphenyl)-2-oxoethyl)-1H-pyrazol-3(2 H)-one (AAP) sensor was synthesized and well characterized. AAP sensor was developed for direct detection of ultra-traces of Fe3+ ions in industrial wastewater and the obtained results were validated through comparison with flame atomic spectroscopy. The turn on fluorescent AAP sensor worked excellently at pH 4.0 and the detection limit was 1.59 nmol L−1 through ESIPT inhibition mechanism. In addition, AAP exhibited high selectivity, sensitivity, fast, direct and efficient response towards Fe3+ ions. The effect of interfering cations commonly present in water was also examined. Furthermore, AAP sensor was successfully integrated in test strips for fluorescent detection of Fe3+ ions with no signal is recorded against interfering cations.