Andesite, trace element determination

A peak in accurate trace element analysis appears to have been reached in the early 1970 s. There are three reasons for this. Firstly, the number of standard samples in circulation was small, with attention directed upon the six United States Geological Survey (USGS) standards (peridotite PCC-1, dunite DTS-1, basalt BCR-1, andesite AGV-1, granodiorite GSP-1 and granite G-2) which supplemented G-1 and W-1. Secondly, many new methods of analysis were being introduced, so that careful interlaboratory calibration was important to demonstrate the reliability of the new techniques. Thirdly, the arrival of the lunar samples placed a premium on high quality analyses of this unique material, access to the samples being denied to laboratories whose data were shown to be in error. The situation since that time has deteriorated, and the quality of many published trace element determinations appears to be little better than in the 1960 s. 

Another analytical procedure for sample preparation including analyte separation and enrichment is the coprecipitation of the trace elements to be determined. The co-precipitation behaviour of Ti, Mo, Sn and Sb under two different fluoride forming conditions (at < 70 °C in an ultrasonic bath and at 245 °C using a Teflon bomb) has been studied to improve the accuracy of the trace analysis of these elements in Ca-Al-Mg fluorides, by ICP-MS.14 The applicability of this analytical method (including isotope dilution technique) was demonstrated for four carbonaceous chondrites and silicate reference materials of basalt or andesite.14... 

Brenan J. M., Shaw H. E., Ryerson E. J., and Phinney D. L. (1996) Erratum to Experimental determination of trace-element partitioning between pargasite and a synthetic hydrous andesitic melt [Earth Planet Sci. Lett. 135 (1995) 1-11]. Earth Planet. Sci. Lett. 140, 287-288. 

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