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An Efficient Sample Preparation Method to Enhance Carbohydrate Ion Signals in Matrix-assisted Laser Desorption/Ionization Mass Spectrometry
Published on: July 29, 2018
Coffee-ring effects in laser desorption/ionization mass spectrometry.
Jie-Bi Hu1, Yu-Chie Chen, Pawel L Urban
1Department of Applied Chemistry, National Chiao Tung University, 1001 University Rd, Hsinchu, 300, Taiwan.
Analytica Chimica Acta
|February 23, 2013
Summary
The "coffee-ring effect" in laser desorption/ionization mass spectrometry (LDI-MS) creates uneven small molecule distribution, impacting analysis. This phenomenon can be hidden but detected with imaging, and partially reduced during sample preparation.
Area of Science:
- Analytical Chemistry
- Chemical Physics
- Spectroscopy
Background:
- Small molecule analysis using laser desorption/ionization mass spectrometry (LDI-MS) is crucial for various scientific fields.
- The physical processes governing sample deposit formation can significantly influence analytical results.
- Understanding analyte distribution in dried droplets is key to improving mass spectrometry techniques.
Purpose of the Study:
- To investigate the heterogeneous distribution of small molecules in dried deposits relevant to LDI-MS.
- To examine the "coffee-ring effect" in matrix-assisted laser desorption/ionization (MALDI) and surface-assisted laser desorption/ionization (SALDI) sample spots.
- To explore the implications of analyte distribution for chemical analysis and mass spectrometry reproducibility.
Main Methods:
- Utilized mass spectrometry imaging capabilities of modern mass spectrometers.
- Investigated "coffee-ring" formation in MALDI and SALDI sample spots.
- Employed optical microscopy and MALDI-MS imaging to analyze sample homogeneity and distribution.
Main Results:
- The "coffee-ring effect" leads to heterogeneous distribution of analytes and matrices in MALDI/SALDI samples, affecting analytical performance.
- This effect can be both disadvantageous (compromising reproducibility) and advantageous (enabling partial separation of analytes).
- A "hidden coffee-ring effect" was observed, where deposits appear homogeneous optically but show heterogeneity via MALDI-MS imaging.
- The coffee-ring effect can be partially suppressed during SALDI sample preparation.
Conclusions:
- The "coffee-ring effect" significantly impacts small molecule distribution in LDI-MS, influencing analytical outcomes.
- MALDI-MS imaging is essential for detecting "hidden coffee rings" not visible by optical microscopy.
- SALDI sample preparation offers potential for mitigating the coffee-ring effect, improving analytical consistency.
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