Determination of silver in biological materials by high-frequency plasma-torch emission spectrometry

Nanogram amounts or silver in small samples of biological materials can be determined by high-frequency plasma-torch emission spectrometry. Samples are digested with perchloric and nitric acids, silver is collected with a bismuth iodide carrier, and the precipitate is decomposed with concentrated nitric acid before dilution. Bismuth shows an enhancing effect on the silver emission at 328.06 nm, and the sensitivity is further improved by elimination of moisture in the aerosol with a second condenser at -3 to -5°C. The detection limit is 0.5 ng per 0.2 ml of sample solution. Condensed milk and whole blood were analyzed satisfactorily.