Atomic absorption spectrophotometric determination of selected elements in ferromanganese nodules from the Pacific and Southern Oceans

The metal content of selected manganese nodules from the Pacific and Southern oceans was determined as follows: boiling of a suspension of 100 mg sample in 25 ml of 4 M hydrochloride acid; filtering the acid leachate through 0.2 ~m membrane filters pre-rinsed with 4 N HC1; diluting the filtrate to 100 ml with distilled water; analysing the metal concentrations by atomic absorption spectrometry with standard solutions prepared in 1 M hydrochloride acid.