Determination of Sudan dyes in environmental water by magnetic mesoporous microsphere-based solid phase extraction ultra fast liquid chromatography

The magnetic mesoporous microsphere-based extraction method coupled with ultra fast liquid chromatography (UFLC) was applied for the extraction and determination of Sudan dyes in environmental water samples. Fe3O4@SiO2 microspheres consisting of a Fe3O4 particle core and an ordered mesoporous silica shell were used. The Fe3O4 particles were prepared simply by a solvothermal reduction method. The mesoporous silica was prepared and coated on the Fe3O4 particles via a surfactant-templating approach by stirring at room temperature. The obtained Fe3O4@SiO2 microspheres possess superparamagnetism and a good mesoporous structure. The experimental parameters, including the amount of Fe3O4@SiO2 microspheres, the pH value of sample solution, extraction time, separation time, elution solvent, volume of elution solvent and elution time, were optimized. Under the optimized conditions, Fe3O4@SiO2 microspheres were successfully used to extract Sudan dyes in the environmental water samples and the enrichment factor is 500-fold. The result showed that the method had good linearity (r = 0.990-0.997), and the limits of detection (LODs) were from 0.082 to 0.12 ng ml(-1). Recoveries obtained by analyzing the five spiked water samples were in the range of 87.10-111.4% and the intra-day and inter-day relative standard deviations (RSDs) were between 0.590 and 7.94%. The results indicated that the novel method could be applied successfully for the determination of Sudan dyes in environmental water samples.