Microwave-induced Plasma Optical Emission Spectrometry Research Articles

A geração química de vapor em espectrometria atômica

The historical development of atomic spectrometry techniques based on chemical vapor generation by both batch and flow injection sampling formats is presented. Detection via atomic absorption spectrometry (AAS), microwave induced plasma optical emission spectrometry (MIP-OES), inductively coupled plasma optical emission spectrometry (ICP-OES) , inductively coupled plasma mass spectrometry (ICP-MS) and furnace atomic nonthermal excitation spectrometry (FANES) are considered. Hydride generation is separately considered in contrast to other methods of generation of volatile derivatives. Hg ¾ CVAAS (cold vapor atomic absorption spectrometry) is not considered here. The current state-of-the-art, including extension, advantages and limitations of this approach is discussed.

A novel sample introduction system for microwave-induced plasma optical emission spectrometry

A newly developed micro-sampling technique using a discrete sample introduction system (DSIS) has been demonstrated for simultaneous multi-element analysis by microwave-induced plasma optical emission spectrometry (MIP-OES). A microliter volume of sample solution (20 μl) is manually inserted into a Teflon microsampling device and subsequently pumped at low solution uptake rates of <100 μl min −1 to a Meinhard-type concentric nebulizer and then into a 250-W helium plasma. The performance of DSIS-MIP-OES was demonstrated by the determination of major (Na, K, Ca, Mg), minor (Cu, Fe, Zn) and trace (Sr) elements in two clinical standard certified reference materials (serum, hair). Standard microaddition procedures were used to minimize possible matrix interference. The detection limit (3σ) obtained was 10, 30, 50, 100, 10, 5, 20 and 40 ng ml −1 for Ca, Cu, Fe, K, Mg, Na, Sr and Zn, respectively. The method offers relatively good precision (RSD ranged from 5 to 14%) and microsampling capability. Agreement between analytical results and certified values for the test elements was good. The method could be useful as a routine clinical laboratory procedure.

Microwave-induced plasma–optical emission spectrometry – fundamental aspects and applications in metal speciation analysis

In the first part of this review, a summary is given of the historical development and fundamental aspects of microwave-induced plasmas (MIPs) and their physical properties. The different methods for temperature and electron density measurements are used to explain the basic concepts and the implications for their application to analytical chemistry. The various types and modifications of MIPs are briefly described and classified in their plasma-spectrochemical context. The second part focuses on the applications of MIPs combined with optical emission spectrometry (OES) for metal speciation purposes. The combination of MIP–OES with different chromatographic and electrophoretic separation techniques has potential, but also limitations, which are outlined and described using several applications which are documented in the literature. Using these examples, the development of a new hyphenated technique based on MIP–OES is indicated.

Applicability of microwave induced plasma optical emission spectrometry (MIP-OES) for continuous monitoring of mercury in flue gases

The applicability of microwave-induced plasma optical emission spectrometry (MIP-OES) for continuous monitoring of the environmentally hazardous element mercury in flue gases has been studied. Microwave induced plasmas have been sustained using both a TM010 cavity (Beenakker resonator) and a so-called Surfatron. The analytical figures of merit for mercury in argon and helium discharges with both types of low-power micro-wave discharges have been examined. To determine mercury in artificial stack gases non-mixed argon/nitrogen discharges have been tested using a tangential flow torch design which allows to introduce a metal-loaded nitrogen gas flow as external gas and argon as internal gas. The addition of main flue gas components such as water vapour (concentration <6 g/m3), oxygen (<4% v/v) and carbon dioxide (<15% v/v) decrease the mercury line intensities to a considerable extent. Trace gases (CO, HCl, SO2, NO) in concentrations typical to waste incineration processes have been found to have no effect on the mercury and the argon line intensities. The detection limit of mercury in nitrogen is 8 μg/m3 using the TM010 MIP and 10 μg/m3 using the Surfatron. As such low detection limits are below the emission limit values of present-day environmental legislation MIP-OES is useful for on-line monitoring of mercury.

Simultaneous multi-element analysis of solid samples by laser ablation—microwave-induced plasma optical emission spectrometry

An experimental arrangement for multi-element microanalysis of solid samples by laser ablation-microwave-induced plasma optical emission spectrometry is introduced. The application of optical fibres as the interface between an échelle spectrograph and a gateable optical multi-channel detector head allows simultaneous measurements of up to ten elements with single laser shots and investigations of element correlation in samples from shot to shot. Correlation measurements of trace elements in steel and aluminum and sodium and lithium in high-purity quartz are given as examples.