Competence azo dyes sensors of new based fluorophores for spectrophotometric trace determination of cobalt in real water samples

In this work, a simple, time saving, accurate and sensitive method for the direct spectrophotometric detection of cobalt ion using two new fluorophore azo dyes, R1 and R2, were achieved. The method based on a complex formation between Co(II) and these two azo compounds-based fluorene and pyrene moieties. To attain the optimal conditions for the detection of cobalt ion, several parameters such as effect of solvents, pH, reagent concentration, sequence of addition, temperature and time were explored. The absorption maximum for Co(II)R1 and Co(II)-R1 orange color complexes was accomplished at 472 nm using pH 8.97 of universal buffer and 470 nm using pH 10.98, respectively. The calibration graphs were linear over the concentration range of 0.2-3 and 0.4-3 mu g mL-1 of Co(II) for Co(II)-R1 and Co(II)-R1, respectively with a stoichiometric ratio of (1:2) (Co2+: reagent). Various statistical analytical parameters including molar absorptivity, limit of detection, limit of quantification, precision and accuracy were estimated. In addition, the established approach was efficiently exploited for Co(II) determination in some water samples. The findings of this investigation may pave the way for advancements in sensor technologies.