Organic Ion-Associate Phase Microextraction/Back-Microextraction for Preconcentration: Determination of Nickel in Environmental Water Using 2-Thenoyltrifluoroacetone via GF-AAS

An ion-associate phase (IAP) microextraction/ back-microextraction system was applied for the enrichment, separation, and detection of trace amounts nickel from environmental water samples. Thenoyltrifluoroacetone (HTTA) acted not only as a chelating reagent nickel, but also component extraction phase, i.e., IAP. Nickel in 40 mL sample solution pH-adjusted with phenolsulfonate (PS−) tetramethylammonium hydroxide converted by chelation reaction presence thenoyltrifluoroacetonate (TTA−). When benzyldodecyldimethylammonium ion (C12BzDMA+) added, suspension IAP formed solution. The consisted TTA−, reagent, PS−, pH buffer, C12BzDMA+, which helps extract complex. centrifuged, separated nickel-TTA chelate extracted into bottom centrifuge tube. After aqueous taken away, 100 µL nitric acid (2 M) containing phosphate used to back-microextract measured via graphite-furnace atomic-absorption spectrometry (GF-AAS). proposed method facilitated 400-fold enrichment. limit 0.02 µg L−1. determination river seawater