fe3o4 magnetic nanoparticles modified with sodium dodecyl sulfate for removal of basic orange 21 and basic orange 22 from complex food samples with high-performance liquid chromatographic analysis

A new method based on sodium dodecyl sulfonate (sds)-coated fe3o4 magnetic nanoparticles (mnps) as an efficient solid-phase adsorbent was developed for the extraction and determination of basic orange 21 and basic orange 22 by using solid-phase extraction coupled with an hplc technique. mnps were prepared via the solvothermal method, and characterized by an infrared spectrometry and a transmission electron microscope. the adsorption capacity was evaluated as 76.8 and 93.5 mg/g for basic orange 21 and basic orange 22, respectively, through langmuir adsorption isotherm model. the experimental conditions were optimized, including the amounts of fe3o4 nps (10 mg) and sds (1.0 ml 2.0 mg/ml), ph value of media (4.5), elution solvent and volume (1.0 ml methanol), and the rate of organic solvent and water of sample solution (methanol/water = 5%, v/v). under optimal experimental conditions, the two dyes showed good linearities in the range of 0.02–5.0 μg/ml (r = 0.9999) with the lods of 0.88 and 0.53 μg/kg for basic orange 21 and basic orange 22, respectively. the presented method was applied successfully to determine basic orange 21 and basic orange 22 in various food samples including dried beancurd stick, yellow fish, drinks, and wine. the recoveries were 72.1–98.3% with rsd of 2.1–9.4%, respectively. and the extraction procedure only needed no more than 13 min. notably, mnps show a good adsorption performance for the two target dyes within a wide ph range and excellent reusability during at least eight times of extraction procedures.