University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Website: @unf

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Classification: Biological material -> hair -> human -> child

Citations 1

"Simultaneous Determination Of Copper And Zinc In The Hair Of Children By PH Gradient Construction In A Flow Injection System"
Analyst 1995 Volume 120, Issue 2 Pages 569-572
Renmin Liu, Daojie Liu, Ailing Sun and Guihua Liu

Abstract: Hair was washed with acetone and water and then dry-ashed at 450°C. The residue was dissolved in HNO3. The pH of the solution was adjusted to 5 and the solution was diluted to 50 mL with masking agent solution (prepared by dissolving 1.6 g sodium citrate, 1.5 g sodium triphosphate and 0.06 g 1,10-phenanthroline in 800 mL of water, adjusting the pH to 5 and diluting to 1 l). A portion (1.2 ml) of the resulting solution was injected into a carrier stream (1.5 ml/min) of boric acid/KCl buffer of pH 9.5 and merged with a reagent stream (0.5 ml/min) of 0.03% zincon. The mixture was passed through a reaction coil and the absorbance was measured at 606 nm. Three peaks were obtained. The first and third peaks corresponded to the sum of Cu and Zn and the second peak corresponded to Cu; Zn was found by difference. The first and second peaks were used for quantification. The calibration graphs were linear from 0.1-3 µg/ml of Cu and from 0.4-12 µg/ml of Zn. The detection limits were 0.02 µg/ml of Cu and 0.12 µg/ml of Zn. The RSD for 0.5 µg/ml of Cu and 2 µg/ml of Zn were 0.8% and 1.1%, respectively. Recoveries were 90-105% for Cu and 96-102% for Zn. The throughput was 20-30 samples/h. The results agreed with those obtained by AAS. A flow injection method is described for the simultaneous determination of copper and zinc with a single detector using the pH gradient technique. Zincon is used as the color reagent for the spectrophotometric determination. The linear range for the determination of zinc is 0.4-12 µg mL-1 and for copper is 0.1- 3.0 µg mL-1. About 20-30 samples can be determined in one hour. The proposed method has been applied to the determination of zinc and copper in childrens' hair.
Copper Zinc Spectrophotometry Simultaneous analysis Method comparison Signal processing Complexation pH gradient