A novel selective and precise optical thin film sensor reliant on the incorporation of synthesized 2-(2'-hydroxynaphthylazo)-benzothiazole (HNABT) as a selective ionophore into the nonporous of a clear glass like material via the sol-gel process is examined for its ability to assess Mn(II) ions in aqueous solutions. The sensor was constructed by spin-coating prepared sol onto a glass plate and the influence of sonication time on immobilization of HNABT into silica matrix was demonstrated through calculation of leaching percentage. The results designated that a sonication time of 25 min is the optimum to accomplish more stable thin films without fluctuation in sensitivity and response time of the introduced sensor for a wide period. The offered sensor can be employed to evaluate Mn(II) ions within the range of 6.0 × 10-8 - 1.5 × 10-5 M with detection and quantification limits of 1.7 × 10-8 and 5.5 × 10-8 M, respectively. The relative standard deviation of 2.1 and 0.83% for reproducibility and repeatability, are assessed, along with a rapid response time of ≈3.0 min. The constructed optode is stable in wet circumstances and should be kept for at least four weeks without detecting any variation in its sensitivity. The recommended sensor was successfully performed to estimate Mn(II) in food, saline effluents, tea leaves, biological and water samples, and the results were established by the GFAAS method.
Keywords: Azo dyes; Environmental analysis; Manganese determination; Optical thin film sensor; Spectrophotometry.
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