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Improved Background Correction in the Analysis Of Cadmium by Flame Atomic Absorption
Author(s) -
GOGUEL Reiner
Publication year - 1983
Publication title -
geostandards newsletter
Language(s) - English
Resource type - Journals
eISSN - 1751-908X
pISSN - 0150-5505
DOI - 10.1111/j.1751-908x.1983.tb00396.x
Subject(s) - cadmium , atomic absorption spectroscopy , hydrofluoric acid , analytical chemistry (journal) , nitric acid , chemistry , arsenic , detection limit , matrix (chemical analysis) , dissolution , inorganic chemistry , environmental chemistry , chromatography , physics , organic chemistry , quantum mechanics
Cadmium signals obtained by direct aspiration of highly concentrated solutions of rocks and other geochemical samples are swamped by strong matrix background signals. Mainly because of iron interference, the deuterium source or other continua are not satisfactory for background correction. In order to isolate atomic absorption by cadmium the total signal and the background signal have to be measured precisely. Sequential measurements in the double beam mode with electrodeless discharge lamps of cadmium and arsenic at 228.80 and 228.81 nm produced a set of uninterfered data for cadmium within marginally useful detection limits of (0.10 ppm in granite, 0.16 ppm Cd in limestone). Simple extraction of the sample powders with nitric acid dissolves only part of the sample matrix but most of the cadmium. In this way higher relative and absolute cadmium concentrations in solution and better detection limits are obtained (e.g. 0.02 ppm Cd in granite). This approach allows cadmium in geosamples at levels below 0.3 ppm to be determined more accurately than via hydrofluoric acid dissolution.