A Simple and Green Vortex-Assisted Switchable Solvent-Based Microextraction Method by Using Schiff Base Ligand Complexation for Iron Determination in Mineral Spring Water Samples Prior to Slotted Quartz Tube Flame Atomic Absorption Spectrophotometry

In this study, a vortex-assisted switchable solvent microextraction (VA-SSME) method was developed for the determination of iron by slotted quartz tube flame atomic absorption spectrometry (SQT-FAAS). A ligand synthesized from the reaction of ortho-phenylenediamine and 5-bromosalicylaldehyde was used to form a coordinate complex of iron. All experimental variables such as switchable solvent amount, sodium hydroxide concentration, sodium hydroxide amount, and diluent amount were optimized to increase extraction efficiency for the iron complex. Optimum conditions were applied to aqueous standard solutions in the range of 20–750 ng/mL, and the percent relative standard deviation (%RSD) was less than 2.0%. The limit of detection (LOD) and limit of quantification (LOQ) were determined as 4.8 and 16.2 ng/mL, respectively. The optimized method recorded approximately 53 times enhancement according to the conventional FAAS system. The proposed method was applied to mineral spring water samples, and satisfactory percent recovery results (100–105%) were obtained for iron, indicating good applicability in addition to high accuracy.