fluorescence sensor for guaifenesin detection in blood serum and pharmaceutical samples based on poly vinyl alcohol-borax hydrogel film modified by manganese doped zinc sulfide quantum dots

Guaifenesin is a commonly used expectorant medicine to treat the symptoms of coughs caused by cold and mild upper respiratory tract infections such as pharyngitis, sinusitis and bronchitis. in veterinary medicine, guaifenesin is given intravenously to induce muscle relaxation when administering anesthesia. guaifenesin relaxes both laryngeal and pharyngeal muscles, allowing easier intubation. guaifenesin (3-(2-methoxyphenoxy)-1,2-propanediol), or glyceryl guaiacolate ether (gge), was originally derived from the guaiac tree [1,2]. in this work, a new turn-on fluorescence probe tin film sensor has been designed for guaifenesin monitoring based on embedding of l-cysteine capped manganese-doped zinc sulfide quantum dot into polyvinyl alcohol and borax hydrogel (pbh). the synthesized quantum dots are dissolved in a polyvinyl alcohol solution by dropwise adding the amounts of borax solution in the mixture. quantum dots are trapped into the hydrogel frame simultaneously with the formation of a three dimensional network of pbh. the characterization and morphology of the new hydrogel nanocomposite tin film was investigated by energy dispersive x-ray microanalysis, tem and average particle size analyzer. it was also observed that the fluorescence intensity of pbh functionalized by l-cysteine capped manganese-doped zinc sulfide quantum dot was enhanced by spraying guaifenesin on the film. this probe shows a linear calibration curve in the range of 0.5–10 µg ml−1 with a detection limit of 0.15 µg ml−1. moreover, relative standard deviation of the sensing platform was 1.15 and 1.07 % (n = 10) for two concentrations of 5 and 7 µg ml−1 respectively. the present sensing system was utilized for guaifenesin assay in human blood serums and regular guaifenesin with satisfactory results.