Determination of trace manganese in soil samples by using eco-friendly switchable solvent based liquid phase microextraction-3 holes cut slotted quartz tube-flame atomic absorption spectrometry

This study presents a novel preconcentration and separation method for manganese determination using a green switchable solvent-based liquid-phase microextraction and slotted quartz tube-flame atomic absorption spectrometry (SS-LPME-SQT-FAAS). The switchable solvent was prepared from the mixture of N,N dimethylamine and ultrapure water, using dry carbon dioxide for protonation. A coordinate complex of manganese was formed with ((E)-2,4-dibromo-6-(((3-hydroxyphenyl)imino)methyl)phenol ligand synthesized in the lab. Parameters including pH, buffer volume, ligand concentration/volume, switchable solvent volume and sodium hydroxide concentration/volume were optimized to enhance complex formation and extraction efficiency. The limit of detection (LOD), limit of quantification (LOD) and enrichment factor were determined as 0.71 µg L−1, 2.4 µg L−1 and 101 folds, respectively. The applicability of the developed method was tested in soil samples using the matrix matching calibration method. The percent recovery results obtained (98–105%) established the method’s accuracy and applicability to real samples.