Gallium chelates

Although radio-immunoassays are rapid and convenient to analyze large numbers of samples, they lack absolute sensitivity and specificity, since cannabinoids cross-react within a given assay. Gas chromatography is no more satisfactory. However, when combined with mass spectrometry it is far more specific and sensitive, although extremely costly. Finally, fluorometric techniques have proved suitable for many applications such as the one based on gallium chelate formation which can only be used for urine (9), and more especially for applications based on cannabinoid dansylation (16-18). However, these last techniques only allow qualitative determination of A9-THC. 

Investigation of the coordination of tetradentate N2S2 ligands has been reported for gallium and indium.79 This type of chelate had previously been incorporated into many technetium complexes for biomedical applications. 

A poly(acrylaminophosphamic-dithiocarbamate) chelating fibre hasbeen used to preconcentratrate several trace metals in seawater by a factor of 200 [957]. The elements included beryllium, bimuth, cobalt, gallium, silver, lead, cadmium, copper, manganese, and indium. ICP-MS was used for detection. 

Preparation. Gallium is extracted from the circulating liquors of the A1203 process, by fractional precipitation, electrolytic process or extraction with chelating agents. 

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