Katrien Poels

Microprobe speciation analysis of inorganic solids by Fourier transform laser mass spectrometry

Fourier transform (FT) laser microprobe mass spectrometry (LMMS) aims at the characterization of local constituents at the surface of solids. Signals from structural fragments specify the main building blocks of the analyte while adduct ions, consisting of one or two intact analyte molecules and a stable ion, allow specific identification of the molecule. A series of inorganic reference compounds including binary salts, oxides, and oxy salts was analyzed to assess the FT LMMS capabilities for the determination of the inorganic molecular composition. Compounds from different classes can be tentatively identified by deductive reasoning while those with the same elements in different stoichiometries require comparison with reference spectra.

Fourier Transform Laser Microprobe Mass Spectrometry for the Molecular Identification of Inorganic Compounds

This study attempted to determine the molecular composition of inorganic analytes at the surface of solids by Fourier transform laser microprobe mass spectrometry (FT LMMS) with an external ion source. A database was established from the analysis of pure compounds. FT LMMS uses a similar ionization as the older LMMS instruments with time-of-flight (TOF) mass analyzer. However, apart from the mass resolution, the mass spectral patterns can be significantly different in FT LMMS compared to TOF LMMS. FT LMMS yields detailed information on the analyte by means of structural fragments, enabling us to specify the main building blocks, as well as adduct ions, consisting of the analyte molecule and a stable ion. Hence, deductive reasoning allows tentative characterization of the analogs without reference spectra, except for compounds with the same elements in different stoichiometries. In that case comparative data are needed.

Speciation of chromium, lead and nickel compounds by laser microprobe mass spectrometry and application to environmental and biological samples☆

Laser microprobe mass spectrometry with time-of-flight analyser is evaluated as a tool to perform speciation of chromium, nickel and lead compounds in solids with a lateral resolution in the μm range. Commercial instruments irradiate the sample at 266 nm while a tunable dye laser is fitted to some experimental set-ups. The analytical merits of both approaches are surveyed and their application to selected test cases in the field of environment and biological tissue analysis at the sub-cellular level is presented. A comparison between TOF LMMS and μ-Raman for the speciation of given components in large industrial airbone particles is discussed.

LASER MICROPROBE MASS SPECTROMETRY: PRINCIPLE AND APPLICATIONS IN BIOLOGY AND MEDICINE☆

Laser microprobe mass spectrometry (LMMS) is an interesting technique for micro‐ and surface analysis. It employs local ionization by a focused laser under high power density conditions and subsequent mass analysis of the generated ions. This paper surveys the main LMMS instruments and their operational principles. Sample preparation is discussed in the context of biological materials. The problem of quantification is addressed. Selected examples show the way that precise information on the molecular composition can be deduced from the detected signals. Both inorganic and organic substances can be identified, even without reference spectra, from in‐situ analysis with a lateral resolution in the order of 1 to 5μm.

Molecular Identification of Foreign Inclusions in Inflammatory Tissue Surrounding Metal Implants by Fourier Transform Laser Microprobe Mass Spectrometry

Fourier transform laser microprobe mass spectrometry (FT LMMS) is a novel technique for micro-analysis of solids with a lateral resolution in the 5 microns range. One of the major advantages of the technique is the capability to perform characterisation of the molecular composition of both organic and inorganic compounds. The information is directly deduced from the signals without the aid of reference spectra. FT LMMS was applied to the characterisation of black tissue fragments in a biopsy from a patient, in which a constrained condylar nodular knee system was implanted ten years ago. The tissue contained numerous foreign giant cells with a black non-birefringent pigment in their cytoplasm. FT LMMS analysis allowed us to detect directly by means of molecular signals, that the debris consisted primarily of titanium oxide and not metallic titanium, while the implant itself only contained titanium.

Feasibility of Fourier transform laser microprobe mass spectrometry for the analysis of lubricating emulsions on rolled aluminium

Additives from lubricating emulsions used in the rolling step of aluminium plate production, are suspected to adhere to the surface and change the surface properties of the metal. The present study aims at investigating the feasibility of a Fourier transform laser microprobe mass spectrometer with external ion source to characterize the organic components at the metal surface. Special attention is given to the possible interactions between the additives and the aluminium. The experiments primarily involve model systems, consisting of aluminium with a thin coating of the individual components or of laboratory-made mixtures.