Deep eutectic solvent-based ligandless ultrasound-assisted liquid-phase microextraction for extraction of cobalt ions from food samples prior to spectrophotometric determination

An innovative environmentally friendly deep eutectic solvent-based ligandless ultrasound-assisted liquid-phase microextraction was introduced for spectrophotometric determination of trace amount of cobalt.n-phenyliminodiacetic acid: choline chloride (2:1 mol ratio) as a novel DES was prepared for extraction of cobalt ions which is both as chelating agent and extraction solvent. The pivotal factors affecting the proposed method including pH, time, temperature, extraction solvent volume, ionic strength, and sample volume were investigated. At optimum conditions, limit of detection and limit of quantification of 5.23 mu g L(-1)and 17.67 mu g L(-1)were achieved respectively. The linear range of 20-200 mu g L(-1)and precision (relative standard deviation %) of 3.4 for 100 mu g L(-1)Co(+2)solution were gained. The proposed method was successfully applied in water samples, tomato sauce, black and green tea, and dark chocolate with high recovery values (%) of 94-105.

Automated summary

An innovative environmentally friendly deep eutectic solvent-based ligandless ultrasound-assisted liquid-phase microextraction method was introduced for the spectrophotometric determination of trace amounts of cobalt. The method showed satisfactory detection limit, quantification limit, linear range, and precision under optimum conditions. It was successfully applied in various samples with high recovery values.