الفهرس 
Physical and Chemical PropertiesOnly 14 pages are availabe for public view
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Abstract
In this work, an analytical technique has been developed using derivative spectrophotometry for the determination of gallium in geological materials.
The following method for the determination of trace quantities of gallium in rocks and minerals is based on the formation of a triple complex between gallium, hydrochloric acid and rhodamine B dye at pH 5 using acetate buffer solution. The complex formation was studied in more details. The complex showed maximum absorption at 578 nm. Beer’s law was obeyed in the concentration range 0.2 – 8 ppm at 574 nm (1st order derivative).
The difficulties arising from the presence of the interfering elements can be overcome in a simple way by isolating gallium and aluminium by precipitation. The interference of aluminium can be overcome by adding sodium fluoride and measuring the absorbance in the 1st order derivative spectrophotometry.
This method was applied on 10 granitic rock samples (5 samples of fresh granites and 5 samples of mineralized granites) which are collected from Gattar area, Eastern Desert, Egypt. An acid digestion procedure was applied for the complete dissolution of the samples. Also, it was applied on two reference samples and 16 samples of separated minerals.
from the statistical calculations, the standard error was 0.2 – 0.8, maximum error % was 2.9 and accuracy was 0.2 – 0.4. This means that, the method is sensitive; accurate in addition to it is simple, rapid and cheap method.