A chemical imaging time-of-flight secondary ion mass spectrometer is described. It consists of a liquid metal ion gun, medium energy resolution reflectron mass analyzer, liquid nitrogen cooled sample stage, preparation chamber and dual stage entry port. Unique features include compatibility with laser postionization experiments, large field of view, cryogenic sample handling capability and high incident ion beam current. Instrument performance is illustrated by the characterization of scanning electron microscopy grids, silver and functionalized polystyrene beads and the postionization of an organic overlayer on a gold substrate.

The benefits of on-site analysis of environmental pollutants are well known, with such techniques increasing sample throughput and reducing the overall cost of pollution level monitoring. This article describes a transportable time-of-flight (TOF) mass spectrometer, based upon a converging, annular TOF (CAT) arrangement. The instrument, the transportable CAT or T-CAT is battery powered and self-contained. The vacuum chamber is never vented and is kept at a very low pressure, even during analysis. Sample gases are admitted to the mass spectrometer via a membrane inlet system. Data collection and analysis are accomplished via a portable PC. The T-CAT is capable of detection limits approaching those of more conventional, nonportable design. The device shows reasonable linearity over wide concentration ranges. Initial results indicate that the T-CAT will be capable of use in a wide range of applications, particularly for environmental monitoring. This article describes the features of the T-CAT, and presents initial results from the membrane inlet/T-CAT system.

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A key issue with any analytical system based on mass spectrometry with no initial separation of compounds is to have a high level of confidence in chemical assignment. This is particularly true for areas of security, such as airports, and recent terrorist attacks have highlighted the need for reliable analytical instrumentation. Proton transfer reaction mass spectrometry is a useful technology for these purposes because the chances of false positives are small owing to the use of a mass spectrometric analysis. However, the detection of an ion at a given m/z for an explosive does not guarantee that that explosive is present. There is still some ambiguity associated with any chemical assignment owing to the presence of isobaric compounds and, depending on mass resolution, ions with the same nominal m/z. In this article we describe how for the first time the use of a radio frequency ion-funnel (RFIF) in the reaction region (drift tube) of a proton transfer reaction-time-of-flight-mass spectrometer (PTR-ToF-MS) can be used to enhance specificity by manipulating the ion-molecule chemistry through collisional induced processes. Results for trinitrotoluene, dinitrotoluenes, and nitrotoluenes are presented to demonstrate the advantages of this new RFIF-PTR-ToF-MS for analytical chemical purposes.

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