Surface sampling by spray-desorption followed by collection for chemical analysis

Area of Science:

• Analytical Chemistry
• Surface Science
• Mass Spectrometry

Background:

• Desorption Electrospray Ionization (DESI) analyzes surface components using electrospray.
• The spray-surface interaction in DESI involves both desorption and ionization processes.

Purpose of the Study:

• To demonstrate a general technique for collecting soluble surface materials using the DESI spray desorption mechanism.
• To enable preconcentration of analytes for enhanced detection by various analytical methods.
• To independently study desorption mechanisms in DESI.

Main Methods:

• Utilizing the spray desorption mechanism of DESI to collect soluble analytes from surfaces onto a collection medium.
• Scanning large areas to collect material onto a smaller area for preconcentration.
• Subsequent analysis of the collection surface using DESI, Gas Chromatography-Mass Spectrometry (GC-MS), and UV-Vis spectroscopy.

Main Results:

• The spray desorption mechanism can be employed as a standalone technique for material collection.
• Preconcentration of low-abundance analytes is achievable by collecting from large areas onto a small surface.
• Optimized DESI conditions represent a compromise between efficient desorption and ionization.

Conclusions:

• The demonstrated technique offers a versatile method for surface material collection and preconcentration.
• This approach facilitates independent investigation of desorption phenomena in DESI.
• The findings highlight the distinct optimization requirements for desorption and ionization in DESI.