Development of a portable time-of-flight membrane inlet mass spectrometer for environmental analysis

Abstract

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.

Membrane introduction Mass Spectrometry: Trends and applications

“…These experiments are often performed by using ion trap mass spectrometers . In a study that uses a ®eld-portable TOF mass spectrometer, a simple membrane inlet has been developed for the on-site analysis of environmental pollutants (White et al, 1998). The reported detection limits were 2.1 ppb, 2.3 ppb, and 3 ppb for benzene, toluene, and xylene, respectively.…”

A non-linear asymmetric error function-based least mean square approach for the analysis of multicomponent mass spectra measured by membrane inlet mass spectrometry

“…22 Utilization of the PLS algorithm for mixture analysis was also recently reported in conjunction with a portable time-of-flight membrane inlet mass spectrometer. 23 In our group a nonlinear asymmetric error function-based least mean square (NALMS) approach for qualitative and quantitative determination of individual compounds based on the multicomponent mass spectra measured by MIMS has been developed. 24,25 This approach is a modification of the general deconvolution method, which assumes that the intensity of any mass-to-charge ratio (m/z) is a linear function of the concentration of the chemical compounds contributing to that particular m/z.…”

Development of Multi-Membrane Near-Infrared Diode Mass Spectrometer for Field Analysis of Aromatic Hydrocarbons

“…During the past few decades, other advancements in volatile compound and gas analysis with the MIMS technique include the development of portable time-offlight mass spectrometers for environmental analysis [11]. The viability of environmental atmospheric monitoring using MIMS sampling has also been examined [3,12].…”