The present paper outlines novel, simple and sensitive method for the determination of copper using spectrophotometry after separation and preconcentration by cloud point extraction. The cloud point methodology was successfully applied for copper determination after complexation with aluminon (triammonium salt of aurintricarboxylic acid), at pH 3.5. Copper(II) ions was quantitatively recovered in Triton X-114 after centrifugation. Acetonitrile (0.2 ml) was added to the surfactant-rich phase prior to its analysis at λ max 538 nm. The influence of analytical factors including complexing agent, buffer solutions, Triton X-114, temperature, heating time, centrifuge rate and time were examined and optimized. The analytical characteristics of the method (e.g. linear range, Ringbom concentration ranges, molar absorptivity, Sandell sensitivity, optimum limits of detection and quantification, enrichment factor, and improvement factors) were evaluated. Linearity was obeyed in the range of 7.5-220 ng/ml of Cu 2+ ion. The detection and quantification limits of the procedure were 2.2 and 7.4 ng/ml of Cu 2+ ion. The tolerance limits of some anions and cations were also examined. The procedure was applied to detect copper in environmental, water and biological samples.

A highly rapid, sensitive, and selective method for the determination of zinc based on the reaction of zinc(II) with 5-amino-2-(phenyldiazenyl)phenol (ACDP) and/or 5-amino-2-(ptolyldiazenyl)phenol (ATDP) and the solid phase extraction of the Zn(II)-ACDP and/or ATDP complex with Amberlite XAD-2000 was developed, in the presence of pH = 5.6 and 6.2 using ACDP and ATDP, respectively, and Triton X-114 medium. ACDP and/or ATDP reacts with zinc to form a violet complex with a molar ratio of 2:1 (ACDP and/or ATDP to zinc). This complex was enriched by the solid phase extraction with Amberlite XAD-2000. An enrichment factor of 500 was obtained by elution of the complex from the resin with a minimal amount of isopentyl alcohol (0.2 ml). In isopentyl alcohol medium, the molar absorptivity of the complex is 1.13 × 10 6 and 1.37 × 10 6 L/mol cm at 647 and 662 nm using ACDP and ATDP, respectively, against a reagent blank prepared in a similar way without zinc. Beer's law is obeyed in the range of 5.0-160 ng/ml in the measured solution. The relative standard deviation for 10 replicate samples of 50 ng/ml level is 1.26 and 1.47%, respectively. The detection and quantification limits reaches 1.5 and 4.7 ng/ml in the original samples. The presented procedure was successfully applied for determination of zinc content in real samples such as waters, food, milk, and biological samples with satisfactory results.

A highly rapid, sensitive, and selective method for the determination of zinc based on the reaction of zinc(II) with 5-amino-2-(phenyldiazenyl)phenol (ACDP) and/or 5-amino-2-(ptolyldiazenyl)phenol (ATDP) and the solid phase extraction of the Zn(II)-ACDP and/or ATDP complex with Amberlite XAD-2000 was developed, in the presence of pH = 5.6 and 6.2 using ACDP and ATDP, respectively, and Triton X-114 medium. ACDP and/or ATDP reacts with zinc to form a violet complex with a molar ratio of 2:1 (ACDP and/or ATDP to zinc). This complex was enriched by the solid phase extraction with Amberlite XAD-2000. An enrichment factor of 500 was obtained by elution of the complex from the resin with a minimal amount of isopentyl alcohol (0.2 ml). In isopentyl alcohol medium, the molar absorptivity of the complex is 1.13 × 10 6 and 1.37 × 10 6 L/mol cm at 647 and 662 nm using ACDP and ATDP, respectively, against a reagent blank prepared in a similar way without zinc. Beer's law is obeyed in the range of 5.0-160 ng/ml in the measured solution. The relative standard deviation for 10 replicate samples of 50 ng/ml level is 1.26 and 1.47%, respectively. The detection and quantification limits reaches 1.5 and 4.7 ng/ml in the original samples. The presented procedure was successfully applied for determination of zinc content in real samples such as waters, food, milk, and biological samples with satisfactory results.