Switchable-hydrophilicity solvent liquid-liquid microextraction prior to magnetic nanoparticle-based dispersive solid-phase microextraction for spectrophotometric determination of erythrosine in food and other samples.

A combination of switchable-hydrophilicity liquid-liquid microextraction prior to magnetic nanoparticle-based dispersive solid-phase microextraction is proposed for the determination of erythrosine using UV/Vis spectrophotometry at 520 nm. Under optimum conditions (i.e., 1.0 mL octylamine as the extraction solvent, 1.5 mL of 10.0 M sodium hydroxide as the phase separation trigger, pH 4.0, 750 µL of acetone as the eluent, 10.0 mg of Fe3O4@XAD-16 as the adsorbent, and 15.0 mL of the sample solution), the method showed a superior analytical performance with limits of detection less than 25.9 ng mL-1, limits of quantitation less than 86.3 ng mL-1 and linear dynamic ranges ranging between 86.3 and 1000 ng mL-1. Percentage relative standard deviations were less than 4.1 and 7.2% for intra-day and inter-day, respectively. The method was successfully applied for the extraction and determination of erythrosine in food samples and other consumer products with recoveries in the range of 94.6-103.9% and within extraction time of 7.8 min per sample.

Process development for the removal and recovery of hazardous dye erythrosine from wastewater by waste materials-Bottom Ash and De-Oiled Soya as adsorbents.

Erythrosine is a water-soluble xanthene class of dye. It is widely used as colorant in foods, textiles, drugs and cosmetics. It is highly toxic, causes various types of allergies, thyroid activities, carcinogenicity, DNA damage behaviour, neurotoxicity and xenoestrogen nature in the humans and animals. The photochemical and biochemical degradation of the erythrosine is not recommended due to formation of toxic by-products. The present paper is an attempt to remove erythrosine from wastewater using adsorption over Bottom Ash-a power plant waste and De-Oiled Soya-an agricultural waste. Under the batch studies, effect of concentration of dye, temperature, pH of the solution, dosage of adsorbents, sieve size of adsorbents, etc., have been studied for the uptake of the dye over both adsorbents. The adsorption process verifies Langmuir and Freundlich adsorption isotherms in both the cases and based on the data different thermodynamic parameters have been evaluated. Batch studies also include kinetic measurements, rate constant study, mass transfer behaviour and establishment of mechanistic pathway for both the cases. For the bulk removal of the dye column operations have been carried out and breakthrough capacities of the Bottom Ash and De-Oiled Soya columns have been calculated. Attempts have also been made for the recovery of the adsorbed dye from exhausted columns by eluting dilute NaOH and more than 90% of the dye was recovered.