Micro-funnel magnetic stirring-assisted liquid–liquid microextraction technique combined with UV–Vis spectrophotometry for determination of thorium in aqueous samples with the aid of experimental design

In this study, trace amounts of thorium ions were extracted using a highly sensitive, selective, rapid and simple micro-funnel magnetic stirring-assisted liquid–liquid microextraction method, and determined by UV–Vis spectrophotometry. Tri-n-octylphosphine oxide was used as the complexing agent during the microextraction process, and Arsenazo III was applied as the chromogenic reagent through spectrophotometric determination. The effective parameters on extraction efficiency were optimized by experimental design methods. Under the optimum conditions, detection limit, relative standard deviation and the enrichment factor were 0.98 μg L −1 , 0.69% and 152, respectively. The calibration graph was linear over the range of 5–250 μg L −1 .