Precise Determination of Rare Earth Elements in Geological Standard Rocks by Inductively Coupled Plasma Source Mass Spectrometry

Abstract

Akimasa MASUDARare earth element (REE) determinations with high accuracy and precision were performed on four geological standard rocks (JA-l, JB-l, -2 and -3) by inductively coupled plasma-mass spectrometry (ICP-MS). In order to achieve this, internal standardization, matrix matching or separation of REE from the matrix elements are recommended. In these analyses, REE data obtained by ICP-MS show excellent agreement (within 5%) with those obtained by isotope dilution method using thermal ionization mass spectrometer. Among these analytical methods of ICP-MS, the most reliable data can be obtained by analysis using a sample solution free from matrix elements. Mass spectrometry using inductively coupled plasma as an ion source (ICP-MS) is a new technique for elemental and isotopic analysis.'-5 Simultaneous multielement determination of trace elements can be performed by ICP-MS, giving simple spectra and excellent low limits of detection. These advantages are promoting wide application of ICP-MS to various analytical studies such as trace element determination in geochemical samples. [6][7][8][9][10][11] Rare earth element (REE) determinations in geochemical samples have also been carried out by ICP-MS. Date and Gray' reported the measurement of REE in three standard reference silicate rocks (SY-3, GSP-1 and NIM-G) with no pretreatment except removal of silica during acid digestion. They showed relatively good agreement between REE abundance data obtained with ICP-MS and previously published data, the differences being generally 10 -40%. Longerich et al." studied the effects of ICP-MS instrumental parameters on the determination of REE and they determined REE abundances in standard rocks BCR-1 and SY-2 without preconcentration. REE abundances reported by them are 10 -20% lower than the accepted values in most cases. Furthermore, Lichte et al.12 presented REE abundance data using ICP-MS with deviations of 2-50% from those obtained by inductively coupled plasma atomic emission spectrometry (ICP-AES) and neutron activation analysis (NAA). In their analysis by ICP-MS, samples were analyzed directly following an acid digestion and Cd was used as an internal standard element.Although these earlier papers have given an indication of the effectiveness of the ICP-MS technique for REE analysis, more precise data on REE are necessary for the strict interpretation of REE patterns in geochemical samples.Thus, in this paper, we perform REE determinations with ICP-MS by four different analytical approaches described later, aiming at establishment of a reliable analytical method.The REE data obtained by ICP-MS are compared with those obtained by a thermal-ionization mass spectrometric isotope dilution technique (TIMS-ID), which is currently considered to be a "bench mark" technique for REE analysis.

Tetrad effects and fine structures of REE abundance patterns of granitic and rhyolitic rocks: ICP-AES determinations of REE and Y in eight GSJ reference rocks.

“…They concluded that their ICP MS data are in excellent agreement with the MS ID ones within differences of about 5%. Figure AI(A) shows our ICP-AES results for JB-1 com pared with the ICP-MS and MS-ID ones reported by Hirata et al (1988). In Fig.…”

“…ICP-MS is currently one of the most sensitive techniques to analyze all REE. We will make a comparison of our re sults for JB-1 with those by ICP-AES and MS-ID reported by Hirata et al (1988) for further evalu ation of the accuracy of our ICP-AES data. JG-2, JG-3, JR-1, and JR-2) are averaged, except for the case of Eu.…”

“…ICP-mass spectrometry (ICP MS) (Hirata et al, 1988) and high-performance ion chromatography (HPIC) (le Roex and Watkins, 1990) have become new techniques to analyze REE in geochemical samples. We have chosen the analytical method of ICP-AES using a scanning monochromator because of its high cost/perfor mance, simplicity in operating such a type of ICP spectrometers, and moderate sensitivities for REE and Y.…”

Rapid quantitative analysis of Y and REE abundances in XRF glass bead for selected GSJ reference rock standards using Nd-YAG 266nm UV laser ablation ICP-MS.

“…Among them, although the precision and accuracy of the measurements performed by the TIMS and solution ICP-MS was very high, the highly complicated and time consuming chemical decomposition and separation procedures were required. Moreover, great care must be given for possible erroneous analysis due to incomplete sample decomposition (e.g., Longerich et al, 1990;Hirata et al, 1988;Imai, 1990;Yoshida et al, 1992;Ujiie and Imai, 1995).…”

Isotopic and trace element studies for Cenozoic volcanic rocks from western China: implication for a crust-like enriched component in the mantle.

“…Uncertainties in the isotope dilution analyses were 0.5-2%. Th, U, Nb, Co, Ni and Cr were determined with an inductively-coupled plasma-source mass spectrometer (ICP-MS; VG PlasmaQuad), using matrix matching method de scribed by Hirata et al (1988). Uncertainties of the ICP-MS analyses were usually 5%.…”