Determination of Manganese in Coffee and Wastewater Using Deep Eutectic Solvent Based Extraction and Flame Atomic Absorption Spectrometry

Abstract

Deep eutectic solvent based liquid phase microextraction was utilized for the preconcentration of manganese in a simple and effective manner. In the developed analytical method, the extraction of manganese was carried out by using 3-[[(2-hydroxyphenyl)imino]methyl]-2-naphthalenol as the ligand, a choline chloride-phenol mixture as the extraction solvent, and tetrahydrofuran as the emulsifier agent. In order to achieve high detection power, all parameters affecting the extraction output such as the buffer (pH 10, 2.0 mL), ligand solution (0.02% (w/v), 1.50 mL), deep eutectic solvent (molar ratio (1:2), 500 µL), tetrahydrofuran (1.0 mL) and instrumental parameters were optimized. Under the optimum conditions, the limit of detection, limit of quantitation, enrichment in detection power and relative standard deviation were determined to be 0.52 µg L−1, 1.72 µg L−1, 92.9-fold, and 2.7%, respectively. For the purpose of characterizing the accuracy in environmental and food samples, the method was successfully applied to wastewater and coffee samples, and the recovery results were shown to be satisfactory.