Related Experiment Video
Updated: Jul 24, 2026

Compact Quantum Dots for Single-molecule Imaging
Published on: October 9, 2012
Selective flotation-separation and spectrophotometric determination of cadmium using phenanthraquinone
M A Akl1, M E Khalifa, S E Ghazy
1Chemistry Department, Faculty of Science, Mansoura University 35516, PO. Box 70, Mansoura, Egypt. sinfac@mum.mans.eun.eg
Abstract:
A simple, selective and sensitive procedure is described for the preconcentration by flotation followed by spectrophotometric determination of trace amounts of Cd(II). Cadmium forms an intense red 1:2 complex with phenanthraquinone monophenylthiosemicarbazone (PPT) at pH > or = 6. The colored Cd-PPT complex was floated quantitatively with oleic acid (HOL) surfactant at pH 6.5, exhibiting maximum absorbance at 520 nm and having a molar absorptivity of 2.4 x 10(5) L mol(-1) cm(-1). The stability constant of the formed complex is 1.5 x 10(12); log K = 12.2. Beer's law was obeyed over the concentration range 0.01-0.34 mg/L. The Sandell sensitivity and relative standard deviation are 0.4 ng/cm2 and 2.6%, respectively. The results obtained spectrophotometrically were compared to those obtained by AAS analysis. The analytical parameters affecting flotation and hence determination have been thoroughly investigated. The proposed procedure was successfully applied to the determination of Cd(II) traces in certified and real human hair samples as well as in natural waters. The structure of the complex formed and the mechanism of flotation were proposed.
More Related Videos
Related Concept Videos
Qualitative Analysis
For instance, group IV...
Effects of EDTA on End-Point Detection Methods
In the visual method, metal-ion indicators (metallochromic dyes), which have distinct colors in their free and complex forms, are added to the mixture to signal the titration's end point. They form stable complexes with metal ions, but these complexes are weaker than the corresponding metal–EDTA complexes. As a result, EDTA...
Precipitation Titration: Endpoint Detection Methods
In the Volhard method, a standard excess of AgNO3 is first added to the...
Precipitation and Co-precipitation
Extraction: Advanced Methods
Gas Chromatography: Types of Detectors-II

