Kandhro et al.: Journal of aoaC InternatIonal Vol. 97, no. 1, 2014 205 Enrichment of Copper as 1-(2-Pyridylazo)-2-Naphthol Complex by the Combination of Dispersive Liquid–Liquid Microextraction/Flame Atomic Absorption Spectrometry Ghulam a. Kandhro Erciyes University, Fen Faculty, Department of Chemistry, 38039, Kayseri, Turkey; University of Sindh, National Centre of Excellence in Analytical Chemistry, Jamshoro, 76080, Pakistan; Dawood University of Engineering and Technology, Department of Basic Sciences, Mathematics and Humanities, Karachi, 74800, Pakistan mustafa soylaK Erciyes University, Fen Faculty, Department of Chemistry, 38039, Kayseri, Turkey tasneem Gul Kazi University of Sindh, National Centre of Excellence in Analytical Chemistry, Jamshoro, 76080, Pakistan erKan yilmaz Erciyes University, Fen Faculty, Department of Chemistry, 38039, Kayseri, Turkey Received March 15, 2012. Accepted by AK February 6, 2013. Corresponding author’s e-mail: gakandhro@yahoo.com DOI: 10.5740/jaoacint.12-114 RESIDUES AND TRACE ELEMENTS A rapid, simple, selective, economical, and sensitive dispersive liquid-liquid microextraction methodology has been established for the preconcentration of copper (Cu) at trace levels. The Cu(II) was complexed with 1-(2-pyridylazo)-2-naphthol; ethanol and carbon tetrachloride were used as disperser and extraction solvents, respectively. To obtain quantitative recovery of Cu(II), the effects of parameters infuencing its extraction effciency and subsequent determinations, i.e., pH, amount of complexing reagent, extraction time, and type and volume of disperser and extraction solvents, were examined. LOD and LOQ were 0.06 and 0.20 µg/L, respectively. The enrichment factor of the proposed method was 60, and the RSD <5%. TMDA 51.3 and TMDA 70 fortifed water certifed reference materials were analyzed for validation of the procedure. The developed microextraction procedure has been used for the preconcentration of Cu(II) in water samples with acceptable results. C opper (Cu) is an important trace element that plays important roles in various biochemical reactions of human organisms; it also takes part in the metabolism of carbohydrates, lipids, and proteins and in the synthesis and degradation of nucleic acids (1–3). Although Cu(II) is essential for humans and animals, a high concentration of Cu(II) can be harmful, causing nausea, diarrhea, vomiting, irritation of the throat and nose, and toxic free hydroxyl radicals that produce cancer by destroying DNA (4–6). Humans are generally at risk due to exposure to Cu(II) from food, air, drinking water, skin contact, and Cu(II)-containing compounds. Drinking water is an important source of Cu(II) intake. Consequently, trace Cu(II) determination from biological matrixes and water has been a main purpose of research because it is important for toxicological and environmental monitoring (7–9). Many analytical techniques have been used to analyze Cu(II) at low concentration, e.g., electrothermal atomic absorption spectrometry (AAS; 10–12), inductively coupled plasma (ICP)/MS (13, 14), and ICP-optical emission spectrometry (15, 16). These techniques have limited application because they are tedious, have high cost, require complex instrumentation, and are time-consuming. Spectrometric methods are used extensively for quantifcation of metals at trace levels in foodstuff, soil, sediment, and water samples. Flame AAS (FAAS) is an important instrumental technique in these felds, due to its good selectivity, simplicity, and low cost. Although determination of trace metals from environmental samples by FAAS suffers from poor sensitivity (17–22), this disadvantage can be overcome by the combination of appropriate enrichment and separation methods prior to FAAS determination. The analysis of trace levels of Cu(II) in environmental samples commonly includes enrichment and separation steps due to matrix interference or inadequate sensitivity. A variety of methods have been developed for the enrichment of Cu(II) involving different analytical techniques, i.e., coprecipitation, adsorption, classical solvent extraction, cloud point extraction, and membrane fltration (23–25). But there are many drawbacks of these techniques that limit their applications, such as unacceptable enhancement factors (EFs), long analysis times, and high amounts of solvent waste. Dispersive liquid–liquid microextraction (DLLME) was developed by Assadi and co-workers in 2006 (26). The main advantages of the DLLME method are speed, ease of operation, low cost, environmental safety, high EF, high recovery, and no need for particular technical skills apart from conventional extraction methods (26–28). The applications of DLLME are the extraction and separation of metal ligands prior to quantifcation for the analysis of analytes using many analytical methods, among which FAAS is the most extensively used. 1-(2-Pyridylazo)-2-naphthol (PAN) is a sensitive organic reagent used for the determination of metal ions by spectrometric techniques (29–33); therefore, it was chosen as the complexing agent in this study. DLLME was based on a ternary constituent solvent system in which Cu(II) was complexed with PAN, while extraction and disperser solvents were quickly injected into the solution, followed by FAAS determination. The parameters Downloaded from https://academic.oup.com/jaoac/article/97/1/205/5654662 by guest on 31 January 2023