Magnetic Sector ICPMS with Desolvating Micronebulization: Interference-Free Subpicogram Determination of Rare Earth Elements in Natural Samples
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- 作者：M. Paul Field and Robert M. Sherrell
- 刊名：Analytical Chemistry
- 出版年：1998
- 出版时间：November 1, 1998
- 年：1998
- 卷：70
- 期：21
- 页码：4480 - 4486
- 全文大小：66K
- 年卷期：v.70,no.21(November 1, 1998)
- ISSN：1520-6882
文摘
A new method has been developed combining desolvatingmicronebulization with magnetic sector inductively coupledplasma mass spectrometry (ICPMS) for the analysis of all14 stable rare earth elements (REEs) in small samplesof marine particulate matter. Application is demonstratedfor REEs in suspended particles from a deep oceanhydrothermal vent plume and a geological referencematerial. A 100-fold reduction in oxide formation, relative to standard nebulizer-spray chamber sample introduction, makes oxide interference correction negligible,even for samples that are very enriched in Ba and lightREEs. Enriched isotopes for one light and one heavy REE(145Nd and 171Yb) are used as both isotope dilution andinternal standards, providing determination of all theREEs in one analysis. This standardization schemeeliminates the need for multimass drift correction usedpreviously to achieve acceptable accuracy with externalstandardization techniques. Instead, the method exploitscapabilities for accurate and precise determination ofisotope ratios, a principal strength of ICPMS, and themass-independent sensitivity of electric field scans on ourdouble-focusing instrument. We demonstrate overallprecision of 
mages/entities/le.gif">2% (1mages/gifchars/sigma.gif" BORDER=0 >) and accuracy better than 6% forall the REEs (except Er = 8.7%), based on comparisonto recommended values for USGS certified referencematerial BHVO-1 (basalt). This performance is similarto that obtained by full isotope dilution mass spectrometric techniques, but the new method is far simpler,requires 5 min sample-1, and avoids interferences introduced by complex mixtures of enriched isotopes. Sensitivity of (1.2-1.4) × 106 counts s-1 ppb-1 and background intensities of 2-60 counts s-1 provide excellentdetection limits of 1-40 ppq, a 100-fold improvement onestablished ICPMS methods. The low sample introduction rate (100 mages/entities/mgr.gif">L min-1) allows unprecedented absolutedetection limits of 1-20 fg.