Releasing Effects in Flame Photometry. Determination of Calcium

Abstract

Strontium, lanthanum, neodymium, samarium, and yttrium completely release the flame emission of calcium from the depressive effects of sulfate, phosphate, and alumínate. Magnesium, beryllium, barium, and scandium release most of the calcium emission.These cations, when present in high concentration, preferentially form compounds with the depressing anions when the solution is evaporated rapidly in the flame. The mechanism of the interference and releasing effects is

Determination of silicate in waste water by atomic absorption inhibition titration

“…Similar effects have been observed in the determination of these elements by atomic absorption spectrometry (11)(12)(13). Considerable work has been reported on the removal of these interferences (14)(15)(16)(17). In most cases the actual mechanisms of these inhibition effects remain to be elucidated.…”

A possible enhancement of measured calcium in small samples of dryashedcucurbitaembryos as determined by atomic absorption analysis

“…Not only was the sample-size effect removed but an additional depression in Ca level was produced suggesting that the original high Ca level was due to an enhancement effect. A number of authors (8,20,21) advise the use of one or two percent perchloric acid in the samples to ensure a full releasing effect by lanthanum but this does not seem to be the effect seen with cucurbits.…”

Emission Flame Photometry

“…West and Cooke ( 126) found (ethylenedinitrilo) tetraacetate (EDTA) to be an effective releasing agent for the determination of calcium or magnesium in the presence of phosphate or sulfate. Dinnin (26) found strontium and some of the rare earths to be useful for the same purpose. Vainshtein and Lebedev (121,123) show-ed that acetylacetone or 8-quinolinol can be used to eliminate the effect of aluminum on calcium emission.…”