Toward the Next Generation of Atomic Mass Spectrometers

Abstract

Atomic mass spectrometry, embodied principally as ICP mass spectrometry (ICP-MS) and glow discharge mass spectrometry (GDMS), has enjoyed rapid growth during the last decade, yet both methods exhibit shortcomings that would be desirable to reduce or eliminate. Prominent among these shortcomings are drift and limited precision, several troublesome spectral and matrix interferences, and moderate atom-detection efficiency. This last limitation is particularly troublesome when ICP-MS, for example, must be interfaced to analytical systems that deliver extremely small sample volumes or low flow rates or when extremely limited sample sizes must be examined. Such situations are projected to be increasingly common in the next decade because of the importance of biotechnology and nanostructured materials. Overcoming these limitations will require substantial modifications in both sources and mass-spectrometer designs. Sources will be required that are more efficient at sample utilization, aerosol volatilization and atomization and that provide multidimensional information. Similarly, mass spectrometers of the future must be more atom-efficient, should measure all elements and isotopes simultaneously, and must operate on a time scale that is compatible with microsampling and transient-sampling technology. Possible alternative systems that meet these criteria will be outlined and their likely performance assessed. Greatest emphasis is placed on time-of-flight mass spectrometry coupled with an ICP source.