Alan R. Date

Inductively coupled plasma source mass spectrometry using continuum flow ion extraction

An inorganic mass spectrometry system is described that uses an atmospheric pressure inductively coupled plasma (ICP) as an ion source. Solution samples may be introduced directly by nebulisation and the analysis time is about 1 min. Ions are extracted from the bulk plasma without any intervening boundary layer so that the full advantages of the ICP as a hightemperature dissociation and ionisation medium are realised.A quadrupole mass analyser is used with a pulse counting ion detector followed by a multi-channel scaler data system. General background levels are low and a wide range of elements may be determined with detection limits below 1 ng ml–1.Spectra are very simple with few molecular analyte ions and only singly and doubly charged species are found. Mass resolution is adequate to avoid peak overlap and isotope ratio determinations may readily be made with precision below 0.5%, with integration times of about 5 min.The operating characteristics and performance of the system are described and illustrated and the future development potential is discussed.

Plasma source mass spectrometry using an inductively coupled plasma and a high resolution quadrupole mass filter

The performance of an instrument using an inductively coupled plasma as an ion source with a high resolution mass filter to analyse the extracted ions is described. A description of the experimental system is given and the spectral characteristics of the technique are discussed. The current performance of the technique for simple solution analysis is described, and the future potential for trace element analysis and isotope ratio measurement is assessed.

The potential of fire assay and inductively coupled plasma source mass spectrometry for the determination of platinum group elements in geological materials

Preliminary work on the application of fire assay and inductively coupled plasma source mass spectrometry (ICP-MS) to the determination of platinum-group elements (PGEs) in geological materials is described. A combination of the neo-classical nickel sulphide fire assay collection procedure with final determination by ICP-MS is considered in relation to the simplified procedure required for dissolution of the nickel sulphide “button” and the wealth of information inherent in ICP-MS spectra. The method was applied to the determination of five PGEs and gold in the South African standard reference material PTO-1 (now known as SARM-7) and the Canadian standard reference material PTC-1. Isotope dilution analysis was applied to the determination of platinum.

Determination of trace elements in geological samples by inductively coupled plasma source mass spectrometry

Abstract The application of inductively coupled plasma souice mass spectrometry (ICP-MS) to the determination of 27 trace elements in geological samples demonstrates the potential of this new analytical method. Data are presented for 13 trace elements in 3 international standard reference water samples, and 14 rare earth elements in 3 international standard reference silicate rocks.

Progress in plasma source mass spectrometry

Abstract Development work in the application of the inductively coupled plasma to plasma source mass spectrometry is described. Two modes of operation are identified, boundary layer sampling and continuum (or bulk plasma) sampling. Boundary layer sampling is characterized by very high signal-to-background ratios, giving detection limits better than 1 ng ml −1 for a wide range of elements. The technique is applied to solution samples, nebulized at approximately 2.5 ml min −1 . Samples may be processed at a rate of one every few minutes. The performance of the technique under boundary layer sampling conditions is illustrated by the rapid determination of lead isotope ratios in galena samples. Boundary layer sampling suffers from several disadvantages, including salt condensation on the sampling aperture, significant inter-element effects, and complex spectra for elements forming strongly bound oxides. It is currently limited to the analysis of simple solution samples. In order to overcome these disadvantages, continuum sampling has been introduced. System performance is compared to that achieved with boundary layer sampling, and the future potential of the technique in both modes of operation is discussed.

Development progress in plasma source mass spectrometry

Development work in the application of the inductively coupled plasma to plasma source mass spectrometry is described. Preliminary results obtained under continuum (or bulk plasma) sampling conditions are illustrated and compared with previously published boundary layer sampling work. The technique is now shown to be viable for multi-element analysis of complex samples.

The influence of polyatomic ion interferences in analysis by inductively coupled plasma source mass spectrometry (ICP-MS)

Abstract The application of inductively coupled plasma source mass spectrometry (ICP-MS) to the determination of some major, minor and trace elements in limestones and manganese nodules is described. The effect of polyatomic ion interferences characteristic of the sample matrix is evaluated, and the effectiveness of correction procedures is demonstrated. Data are presented for a wide range of elements in three NBS standard reference calcium-rich samples (NBS SRM 1b, 88a and 120b) and the two USGS manganese nodule standard reference materials (Nod-A-1 and Nod-P-1).

On-line pre-concentration and determination of lead in potable water by flow injection atomic absorption spectrometry

A flow injection system incorporating a micro-column of activated alumina was used in conjunction with flame atomic absorption spectrometry for the pre-concentration and determination of lead in drinking waters. The analyte was deposited on the alumina micro-column (basic form of alumina) during the sampling stage and elution was effected by injection of nitric acid (250 µl, 2 M). The procedure was successfully applied to a range of water samples and the accuracy was assessed through recovery experiments, the analysis of a certified reference water and by independent analyses by inductively coupled plasma mass spectrometry. The limit of detection based on a sample volume of 25 ml (sampling time 5 min at 5 ml min–1) was 0.36 µg l–1 and the relative standard deviations at 40 and 4 µg l–1 were 1.4 and 12%, respectively.

Determination of rare earth elements in geological samples by inductively coupled plasma source mass spectrometry

The prototype inductively coupled plasma source mass spectrometer (ICP-MS) operated by the British Geological Survey is described. Preliminary work on its application to the determination of the rare earth elements in geological materials is discussed.

Studies in the determination of lead isotope ratios by inductively coupled plasma mass spectrometry

The application of ICP-MS to the determination of lead isotope ratios in geological materials is described. Data presented for a series of lead mineral concentrates are compared with reference values obtained by conventional solid source thermal ionisation mass spectrometry. The simultaneous determination of lead isotope ratios and trace elements is carried out in a rapid analysis mode. The application of an electrothermal vaporisation technique for small solution aliquots is described. Lead isotope ratio data for the United States Geological Survey standard reference silicate rock BCR-1, obtained without separation of lead from the matrix, are compared with previously published values obtained after separation.