Miniaturization of Mass Spectrometry Analysis Systems

Abstract

The key concepts and technologies developed in our laboratories in Purdue University for the miniaturization of mass spectrometry analysis systems are introduced. Mass analyzers of simple geometries with a novel atmospheric pressure interface were employed allowed reduction in the size of the ion trap mass spectrometer. Ambient ionization methods were developed and coupled to miniature mass spectrometers to allow direct MS analysis of complex samples without sample preparation and chemical separation. The performance of desorption electrospray ionization, low temperature plasma probe, paper spray as well as two handheld MS systems, Mini 10 and Mini 11, are described with demonstrations of capabilities for chemical analysis.

Figure 1

(a) Chemical analysis using lab scale mass spectrometry systems. (b) Conceptual design of a miniature mass spectrometry device for automated chemical analysis.

Figure 2

Desorption electrospray ionization (DESI) for direct sampling ionization for MS analysis. (a) Schematic setup of a DESI for MS analysis. (b) Mass spectrum recorded of desorption ionization of 10pg TNT on paper, negative MS. The inset shows the corresponding tandem mass spectrum. Reprinted with permission from ref. . (c) Automated 2D DESI source for high throughput analysis and imaging. (d) Imaging of rat brain tissue using DESI-MS, m/z = 834, cc: corpus callosum, LV: lateral ventricle. Reprinted with permission from ref. .

Figure 3

Low temperature plasma ionization. (a) Schematic setup of the LTP probe. Adapted with permission from ref. . (b) Detection of 1 ug cocaine on a human finger. Adapted with permission from ref. .

Figure 4

Paper spray ionization. (a) A typical operation process of applying paper spray for analysis of a dried blood spot and the comparison of sprays between paper spray and nano-ESI. Adapted with permission from ref. . (b) Analysis of therapeutic drug in dried blood spot, MS and MS/MS analysis of 400 pg atenolol and 20 pg atenolol, respectively, in 0.4 uL blood. Adapted with permission from ref. .

Figure 5

Handheld miniature mass spectrometers and their analytical performance. (a) Mini 11mass spectrometer, 4 kg and <35W. (b) Monitoring of benzene in air at different concentrations using Mini 10 (10kg, 70W) with APCI. Reprinted with permission from ref. . (c) MS/MS analysis of peptide, Mini 11 with nano-ESI, MRFA 1 ug/ml. Reprinted with permission from ref. . (d) Analysis of proteins using Mini 11 with nano-ESI and extended mass range, Cytochrome C, 200 ug/ml. Reprinted with permission from ref. .