Development of on-line single-drop micro-extraction sequential injection system for electrothermal atomic absorption spectrometric determination of trace metals

• Published in: Analytica chimica acta Vol. 632; no. 2; pp. 216 - 220
• Main Authors: Anthemidis, Aristidis N., Adam, Ibrahim S.I.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 26.01.2009; Elsevier
• Subjects: Analytical chemistry; Atomic spectrometry; Chemistry; Exact sciences and technology; Metal determination; Sequential injection; Single-drop micro-extraction; Spectrometric and optical methods; Sequential injection; Atomic spectrometry; Single-drop micro-extraction; Metal determination; Trace analysis; Water; Cadmium; High performance; Ammonium; Performance characteristic; Sequential extraction; Enhancement factor; Droplet; Ketone; Certified reference material; Chemical enrichment; Sample preparation; Sample cell; Sequential method; Detection limit; Thermoelectric atomization; Sampling; Flow injection; Atomic absorption spectrometry
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2008.10.078

A novel automatic sequential injection (SI) single-drop micro-extraction (SDME) system is proposed as versatile approach for on-line metal preconcentration and/or separation. Coupled to electrothermal atomic absorption spectrometry (ETAAS) the potentials of this SI scheme are demonstrated for trace cadmium determination in water samples. A non-charged complex of cadmium with ammonium diethyldithiophosphate (DDPA) was produced and extracted on-line into a 60 μL micro-drop of di-isobutyl ketone (DIBK). The extraction procedure was performed into a newly designed flow-through extraction cell coupled on a sequential injection manifold. As the complex Cd(II)-DDPA flowed continuously around the micro-droplet, the analyte was extracting into the solvent micro-drop. All the critical parameters were optimized and offered good performance characteristics and high preconcentration ratios. For 600 s micro-extraction time, the enhancement factor was 10 and the sampling frequency was 6 h −1. The detection limit was 0.01 μg L −1 and the precision (RSD at 0.1 μg L −1 of cadmium) was 3.9%. The proposed method was evaluated by analyzing certified reference material.