Iron oxide functionalized graphene oxide as an efficient sorbent for dispersive micro-solid phase extraction of sulfadiazine followed by spectrophotometric and mode-mismatched thermal lens spectrometric determination

•First application of graphene oxide@Fe3O4 in DMSPE of SD.•Development of a simple/sensitive spectrophotometric method for determination of SD.•Application of a novel coupling agent for formation of an azo dye with SD.•Application of homemade mode-mismatched TLS for quantification of the SD.•The method is rapid, simple, cost effective and yield very low detection limit.

A simple and rapid dispersive micro-solid phase extraction (DMSPE) combined with mode-mismatched thermal lens spectrometry as well as fiber optic linear array spectrophotometry was developed for the separation, extraction and determination of sulfadiazine. Graphene oxide was synthesized using the modified Hummers method and functionalized with iron oxide nanoparticles by means of a simple one step chemical coprecipitation method. The synthesized iron oxide functionalized graphene oxide was utilized as an efficient sorbent in DMSPE of sulfadiazine. The retained analyte was eluted by using 180 µL of a 6:4 mixture of methanol/acetic acid solution and was spectrophotometrically determined based on the formation of an azo dye through coupling with thenoyltrifluoroacetone. Under the optimized conditions, with the application of spectrophotometry technique and with a sample volume of 100 mL, the method exhibited a linear dynamic range of 3–80 µg L−1 with a detection limit of 0.82 µg L−1, an enrichment factor of 200 as well as the relative standard deviations of 2.6% and 4.3% (n=6) at 150 µg L−1 level of sulfadiazine for intra- and inter-day analyses, respectively. Whereas, through the application of the thermal lens spectrometry and a sample volume of 10 mL, the method exhibited a linear dynamic range of 1–800 µg L−1 with a detection limit of 0.34 µg L−1 and the relative standard deviations of 3.1% and 5.4% (n=6) at 150 µg L−1 level of sulfadiazine for intra- and inter-day analyses, respectively. The method was successfully applied to the determination of sulfadiazine in milk, honey and water samples.

Graphical abstractA simple, rapid and efficient dispersive micro-solid phase extraction (DMSPE) using iron oxide functionalized graphene oxide combined with mode-mismatched thermal lens spectrophotometry as well as fiber optic linear array spectrophotometry was developed for separation, extraction and determination of sulfadiazine.Figure optionsDownload full-size imageDownload as PowerPoint slide