http://dx.doi.org/10.1007/s00216-012-6531-4">
 

Document Type

Journal Article

Department/Unit

Department of Chemistry

Title

Development, optimization, and use of an APCI source with temperature-controlled vaporization of solid and liquid samples

Language

English

Abstract

A trend is observed in mass spectrometry, in which solid samples without prior dissolution and chromatographic separation are brought directly into the ion source and are ionized, e.g., by corona discharge (Atmospheric Solids Analysis Probe) or plasma (Direct Analysis in Real Time). The Direct Inlet Probe-atmospheric-pressure chemical ionization (APCI) ion source presented here, which was coupled to a high-resolution quadrupole time-of-flight-mass spectrometer, differs from most of the other ion sources in having temperature-programmed heating of the sample. The resulting possibility to reduce ion suppression and ion-molecule reactions in the ion source was shown by the separation of two fatty acid methyl esters as a result of their boiling point difference. Using caffeine as sample, certain source parameters such as the auxiliary gas flow, the drying gas flow, and the position of the probe tip in the ion source were optimized. The ability to perform quantitative analyses was shown by the linear concentration response (R 2 = 0.9984) observed when analyzing different caffeine concentrations. An extract of a Chinese medicinal herb was used to examine the reproducibility (relative standard deviations of the most abundant m/z signals were ≤8.1 %). It was also possible to distinguish milled samples of Radix Angelicae sinensis and Radix Angelicae gigas from each other and to identify the coumarins they contain without sample preparation. Supplying synthetic air instead of nitrogen to the ion source makes APCI in the negative mode possible as well; this was proven by the analysis of n-nonyl-β-d-maltoside. © 2012 Springer-Verlag Berlin Heidelberg.

Keywords

Ambient ionization, Atmospheric-pressure chemical ionization, Chinese herbal medicine, DIP-APCI, Mass spectrometry

Publication Date

2013

Source Publication Title

Analytical and Bioanalytical Chemistry

Volume

405

Issue

4

Start Page

1373

End Page

1381

Publisher

Springer Verlag

ISSN (print)

16182642

ISSN (electronic)

16182650

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