Surface Sampling by Spray-Desorption Followed by Collection for Chemical Analysis

• Published in: Analytical chemistry (Washington) Vol. 82; no. 5; pp. 1674 - 1679
• Main Authors: Venter, Andre R, Kamali, Afrand, Jain, Shashank, Bairu, Semere
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-03-2010
• Subjects: Analytical chemistry; Chemistry; Chromatographic methods and physical methods associated with chromatography; Chromatography; Desorption; Exact sciences and technology; Gas chromatographic methods; Ions; Mass spectrometry; Spectrometric and optical methods; Chemical analysis; Sample; Use; Desorption; Electrospray; Chemical ionization; Chemical enrichment; Gas chromatography; Technique; Surface area; Sampling; Mass spectrometry; Ultraviolet visible spectrometry
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac902013x

Desorption electrospray ionization (DESI) directly analyzes soluble chemical components present on surfaces when a pneumatically assisted electrospray is directed at the sample. Here we demonstrate that the same spray desorption mechanism that operates in DESI can be used as a general technique to collect soluble materials present on surfaces. After desorption analytes are collected on a suitable collection surface, large areas can be scanned and collected onto a small collected area, which allows for preconcentration of low abundance material before analysis. This collection surface can then subsequently be analyzed by DESI but also by many other techniques such as gas chromatography−mass spectrometry or UV−vis spectroscopy. In addition this technique can be used to study desorption mechanisms in DESI independently from ionization mechanisms. Preliminary results indicate that the optimized conditions in DESI are a compromise between those conditions that are optimum for desorption and conditions that lead to efficient ionization.