Releasing agents, atomic spectroscopy

Releasing agent In atomic absorption spectroscopy, species introduced to combine with sample components that would otherwise interfere by forming compounds of low volatility with the analyte. 

The analytical application of atomic-absorption or atomic-emission spectroscopy generally involves obtaining the sample in an appropriate solution for measurement and calibrating the instrument properly. Commonly used methods for different materials are described below. Frequently, a releasing agent will have to be added, or a solvent extraction will be required to concentrate the element and increase the sensitivity. Standards should be treated in a similar manner. 

Several other hydroxides have been used both for general coprecipitation and for specific separations. Lanthanum hydroxide has been used (47, 48) as a convenient collector and subsequent release agent for atomic absorption spectroscopy. Titanium hydroxide coprecipitates copper and zinc from seawater (49), and chromium(III) hydroxide precipitates cadmium(II) (50) and zinc (57). Other authors have used magnesium hydroxide (52, 53), manganese dioxide (54, 55), and zirconium hydroxide (56, 57) to collect trace metals from natural waters. Thallium(III) was coprecipitated with zirconium hydroxide at pH 4.3-6.7 and thallium(I) at pH 7.0-13.0 (57). Beryllium (58) and antimony (59) can be quantitatively coprecipitated with a variety of hydroxides including titanium and zirconium, depending on the pH used. 

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