US EPA

6665713 

Journal Article 

USE OF A SEALED TEFLON VESSEL FOR DECOMPOSITION FOLLOWED BY THE DETERMINATION OF CHEMICAL CONSTITUENTS OF VARIOUS MARINE SAMPLERS 

Noriki, S; Nakanishi, K; Furawa, T; Uematsu, M; Uchida, T; Tsunogai, S 

1980 

31 

4 

354-361 

BCI:BCI198172030113 

A method of chemical decomposition and analysis is proposed for the determination of inorganic elements in various marine materials such as suspended particles collected on filter paper, settling particulate matters obtained with a sediment trap, sediment, plankton and living organisms. A dried and powdered sample of about 50 mg is placed into a decomposition Teflon vessel followed by adding 300 .mu.l of concentrated nitric acid, 300 .mu.l of concentrated perchloric acid and 100 .mu.l of 46% hydrofluoric acid, and the bomb is sealed for 5 h at 150.degree. C. For an organic sample, such as a suspended matter sample on a Nuclepore filter, 300 .mu.l of nitric acid, 300 .mu.l of perchloric acid and 200 .mu.l of hydrofluoric acid are added to the bomb instead of the reagents described above. The chemical constituents dissolved in the bomb are determined with the following simple and sensitive analytical methods. Silicate is determined by the slightly modified Mo yellow colorimetric method in the presence of the decomposition reagents. Other constituents are determined after the digested solution is evaporated to dryness in a Teflon dish and dissolved with a hydrochloric acid solution. Alkali and alkaline earth metals are determined by acetylene-air or acetylene nitrous oxide flame atomic absorption spectrometry. For Al, Fe and Mn, acetylene-air flame or flameless atomic absorption spectrometry is used. Flameless atomic absorption spectrometry is best for the determinations of Cu, Ni, Co and Cd. Phosphate is colorimetrically analyzed with a Mo blue method. The results obtained for a National Bureau of Standards standard sample show a good agreement with the certified values.