Ferromanganese crusts and nodules chemical analyses from the USGS Reston analytical laboratories

Based on comparative studies on the utility of ICP, atomic absorption, and other techniques for the elemental analysis of geological samples the authors decided to pursue a scheme of analysis based primarily around the induction coupled plasma atonic emission spectrometry (ICP) technique because of its simultaneous multielement capability and its relatively large linear concentration range. Atomic Absorption techniques are used only for those elements where the sensitivity, precision, or accuracy of the ICP technique are not sufficient for the determination. The elements Cu, Ni, Mo, Sr, V, Y, Cr, Ba, Co, and P were determined by ICP spectrometry, K, Pb, and Zn by FAA spectrometry and Cr by Zeeman GFAA spectrometry on a concentrated solution of 100mg sample dissolved into 3 mL HN03, 1 mL HC104 and 10 mL HF. Mn, Ti, Al, Fe, Mg and Ca is determined by ICP spectrometry and Cd by Zeeman GFAA spectrometry on a dilution of the previous solution with 3N HCl. A dissolution of 100mg of sample into (1+1) HCl was analysed for As using Zeeman GFAA spectrometry. A fusion of 100mg of sample with a mixture of LiBO2+liB4O2 was analysed for Si and Na using ICP technique. Before analysis, the samples were dried at 110°C overnight and fused at 1000°C for 45 minutes.