Dispersive Liquid–Liquid Microextraction of Nickel Prior to Its Determination by Microsample Injection System-Flame Atomic Absorption Spectrometry

Abstract

A sensitive and simple method for the determination of trace nickel was developed by the combination of dispersive liquid–liquid microextraction (DLLME) and microsample injection system–flame atomic absorption spectrometry (MIS–FAAS). Trace nickel was preconcentrated as the 8-hydroxyquinoline chelate by DLLME, and the conditions were optimized by a Plackett-Burman design. Quantitative recovery of nickel (98 ± 1%) was obtained by a sample volume of 7.5 mL at a pH of 6.0. The enrichment factor was 52.5, and the limits of detection and quantitation were 0.1 µ g L⁻¹ and 3.0 µ g L⁻¹, respectively. The method was validated by the analysis of a wastewater standard reference material, water samples, and a wire sample. The reported method has superior analytical figures of merit compared with similar methods reported in the literature.

Keywords:

• 8-hydroxyquinoline
• Dispersive liquid–liquid microextraction
• DLLME
• Factorial design
• Microinjection system–flame atomic absorption
• MIS-FAAS
• Nickel

Notes

Notes: Factors are defined in Table 1.

^a 0: center point; n.s.p.: no sediment phase; n.d.: not detected.

^a Mean ± standard deviation based on four replicate measurements.

^a Mean ± standard deviation based on four replicate measurements.

^a IL/MBVE: Ionic Liquid/Microvolume Back Extraction; DLLME–SFO: Dispersive Liquid–Liquid Microextraction Based on Solidification of Floating Organic Drop; CPE: Cloud Point Extraction; HF-LPME: Hollow Fiber Based Liquid-Phase Microextraction; SPE: Solid Phase Microextraction; RTIL-DLLME: Room Temperature Ionic Liquid Dispersive Liquid–Liquid Microextraction; FI-FAAS: Flow Injection-Flame Atomic Absorption Spectrometry; ETAAS: Electrothermal Atomic Absorption Spectrometry; MIS-FAAS: Micro Injection System-Flame Atomic Absorption Spectrometry.