Geigy Scientific Tables

Organic-inorganic based nano-conjugate adsorbent for selective palladium(II) detection, separation and recovery

Introduction Fundamental principles of inductively coupled plasmas Instrumentation for ICP-AES Aerosol generation and sample transport in plasma spectrometry Fundamental aspects of ICP-MS Use of ICP-MS for isotope ratio measurements Alternative plasmas and sample introduction systems Environmental applications of plasma spectrometry Geological applications of plasma spectrometry Applications of plasma spectrometry in food science References Index .

Inductively coupled plasma spectrometry and its applications

Dynamic reaction cell ICP-MS for determination of total As, Cr, Se and V in complex matrices: still a challenge? A review.

A new method for urine cadmium biomonitoring is presented. It uses inductively coupled plasma dynamic reaction cell mass spectrometry (ICP-DRC-MS) to eliminate molybdenum-based polyatomic interferences. The method began to be used in the National Health and Nutrition Examination Survey (NHANES) starting with the 2003–2004 survey cycle. Removal of moybdenum-based polyatomic interferences was found to reduce observed urine cadmium concentrations by a signficant amount, 37% at the 50th percentiles, for a subset (N = 2066) of NHANES 2003–2004 urine specimens. To avoid creating an artificial shift in NHANES data with the introduction of this method, urine cadmium results for survey cycles 1999–2000 and 2001–2002 were republished (http://www.cdc.gov/exposurereport/report.htm,1http://www.cdc.gov/nchs/datawh.htm2) after mathematical adjustment correcting for the bias on the basis of their previously determined molybdenum concentrations. Data supporting this mathematical adjustment are presented in this article. Blood cadmium data presented here show that at the normal levels of blood molybdenum, no significant molybdenum-based interferences are observed.

Eliminating molybdenum oxide interference in urine cadmium biomonitoring using ICP-DRC-MS

Noble metals are subject to a number of significant oxide-based interferences in ICP-MS analysis. Quantification of these interferences has been largely overlooked despite evidence which suggests that they may, in some cases, represent a significant source of analytical error. Their removal would therefore constitute a significant improvement in analytical accuracy. In this study the oxides that interfere with noble metal analysis have been quantified relative to CeO+/Ce+ ratios. A dynamic reaction cell (DRC) based solution to the problem is introduced, which works in complete contrast to conventional ICP-MS analysis where the formation of oxides is undesirable and operating conditions are optimised to limit their production. Oxygen reaction gas is utilised actively to promote oxidation of interfering species to higher oxides, with a resulting separation of analyte from interfering oxide. Results are presented for Hf, Ta, Nb, and
Zr where the single oxide interferes with a noble metal analyte mass. Various higher oxides are formed, leaving the mass free from interference. The reaction mechanism has been determined in each case by monitoring of new multiple-oxide species and scans of the entire mass range to identify new product species. Results confirm the success of an in-cell separation of analyte from metal oxide, facilitating improved detection limits and isotope-ratio precision. The suitability of this method for general environmental use is demonstrated by analysis of a certified soil reference material and isotope-ratio analyses.

A dynamic reaction cell (DRC) solution to oxide-based interferences in inductively coupled plasma mass spectrometry (ICP-MS) analysis of the noble metals

A comparison of double-focusing sector field ICP-MS, ICP-OES and octopole collision cell ICP-MS for the high-accuracy determination of calcium in human serum.

Catalysts containing the platinum group elements (PGEs) are employed for a variety of industrial and chemical uses. Palladium (Pd), platinum (Pt) and rhodium (Rh) are the active components in automobile catalytic converters as well as catalysts used in pharmaceutical/biological applications and petroleum refining. In all cases the high economic value of these catalysts means that it is important to be able to measure the precious metal loading very accurately. The aim of this work was to develop a robust and reliable high accuracy/precision method for the analysis of Pd, Pt and Rh metals in autocatalysts with a target expanded uncertainty (i.e., k
				= 2, 95% confidence) of approximately 1% relative. A microwave digestion procedure was developed that provided a relatively quick total dissolution of the precious metals in a 0.2 g sample. An ultrasonic nebuliser with desolvation enabled the effects of the key interferences to be negated. Thus it was possible to make the comparison between a multi-collector ICP-MS and a more conventional quadrupole instrument. For Pd and Pt, high accuracy analysis was underpinned by an approximate matching isotope dilution calibration procedure. In the case of monoisotopic Rh an approximate matching bracketing calibration procedure was used (which had originally been developed for high accuracy ICP-OES) with Ru as the internal standard. Using the procedures reported here, the multi-collector ICP-MS provided data for the NIST autocatalyst reference material (SRM 2556) which showed excellent agreement with the reference values for Pd, Pt and Rh, with expanded uncertainties (i.e., k
				= 2, 95% confidence) of 0.9%, 1.1% and 0.9%, respectively. The equivalent data from the conventional quadrupole ICP-MS shows an approximately two-fold increase in these uncertainty estimates. Such a difference is likely to be very significant when dealing with these very precious materials which have a very high intrinsic economic value.

Lorna A. Simpson

Papers

A dynamic reaction cell (DRC) solution to oxide-based interferences in inductively coupled plasma mass spectrometry (ICP-MS) analysis of the noble metals

A comparison of double-focusing sector field ICP-MS, ICP-OES and octopole collision cell ICP-MS for the high-accuracy determination of calcium in human serum.

The development of a high accuracy method for the analysis of Pd, Pt and Rh in auto catalysts using a multi-collector ICP-MS

A reaction mechanism for solving the oxide problem in ICP-MS analysis for the noble metals