Development of a selective and highly sensitive optical chemical sensor for determination of sulfaguanidine based on a novel mixed isopolymolybdates

We report a novel sensitive and selective optical sensor based on [Eu (dmso)(8)] [Eu (eta(NO3)-N-2)(2)(dmso)(4)(alpha-Mo8O200.5] [Mo6O19] (1) for sulfaguanidine (Sg) determination in environmental water. The complex formation processes between Sg and 1 were studied spectrophotometrically, showing that the stoichiometric ratio was determined as 1:1. The sensing thin film was constructed by spin coating of 1 onto glass plate surface. The proposed membrane shows a significant absorbance signal change on exposure to buffer solution of pH 7 containing Sg. The optode surface topology reveals agglomerations after the Sg detection process proving Sg recognition by the thin film. It displays a calibration response for Sg over a wide concentration range of 10(-11) M to 10(-5) M with a detection limit (LOD) of 6.3 x 10(-13) M and response time of 8 min. This optode exhibits good selectivity toward sulfaguanidine (Sg) in comparison with sulfamethoxazole (SMX), Cloxacillin (Clox), L-cystine (L-cys), tryptophan (tryp), NO3-, and Cl-. The proposed absorbance sensor in this work was found to be stable, has good repeatability, reproducibility and an accepted lifetime. Finally, this optode has been applied for Sg determination in mineral and tap water sample finding encouraged results.