Determination of Trace Platinum in Water Samples by Ionic Liquid-Dispersive Liquid–Liquid Microextraction Combined with Graphite Furnace Atomic Absorption Spectrometry

A new method has been established for determining trace amounts of platinum in water using ion liquid (IL)-dispersive liquid–liquid microextraction (DLLME) combined with graphite furnace atomic absorption spectroscopy (GFAAS). The method is based on the use of a self-prepared reagent, 5-(5-cyano-2-pyridineazo)-2,4-diaminotoluene (5-CN-PADAT), as a chelating agent, which reacts with Pt(IV) to form a hydrophobic chelate. The extraction solvent is 1-octyl-3-methylimidazolium hexafluorophosphate ([C8mim][PF6]), and ethyl acetate is used as the dispersive solvent. After the extraction is completed, the extraction phase formed by [C8mim][PF6] and ethyl acetate has a relatively low viscosity and can be directly used for the determination of GFAAS. A single-factor rotational method was employed to optimize conditions affecting DLLME extraction efficiency. The interactions among the factors affecting DLLME were analyzed using response surface optimization (RSM). Under optimal conditions, platinum concentrations exhibited good linearity within the range of 40–280 ng/mL, with a detection limit of 0.3 ng/mL. AGREEprep was used to discuss the ecological friendliness of the method, demonstrating its low cost, ease of operation, simple equipment requirements, and environmental friendliness. When applied to determining trace amounts of platinum in water samples, the results were satisfactory.