Tip-Enhanced Laser Ablation Sample Transfer for Biomolecule Mass Spectrometry

• Published in: Journal of the American Society for Mass Spectrometry Vol. 26; no. 1; pp. 63 - 70
• Main Authors: Ghorai, Suman, Seneviratne, Chinthaka A., Murray, Kermit K.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-01-2015; Springer Nature B.V
• Subjects: Ablative materials; Analytical Chemistry; Angiotensin II - chemistry; Animals; Anthracene; Atomic force microscopes; Atomic force microscopy; Atomic properties; Bioinformatics; Biotechnology; Cattle; Chemistry; Chemistry and Materials Science; Desorption; Flight operations; Gold; Insulin; Insulin - chemistry; Ionization; Ions; Laser ablation; Lasers; Manuals; Mass spectrometry; Microscopy, Atomic Force; Organic Chemistry; Proteomics; Research Article; Rhodamine 6G; Scientific imaging; Semiconductor lasers; Silver; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods; Spectroscopy; Spots; Thin films; Wire; YAG lasers; Ambient; Laser ablation; Matrix-assisted laser desorption/ionization; Atomic force microscope
• ISSN: 1044-0305; 1879-1123
• DOI: 10.1007/s13361-014-1005-x

Atomic force microscope (AFM) tip-enhanced laser ablation was used to transfer molecules from thin films to a suspended silver wire for off-line mass spectrometry using laser desorption ionization (LDI) and matrix-assisted laser desorption ionization (MALDI). An AFM with a 30 nm radius gold-coated silicon tip was used to image the sample and to hold the tip 15 nm from the surface for material removal using a 355 nm Nd:YAG laser. The ablated material was captured on a silver wire that was held 300 μm vertically and 100 μm horizontally from the tip. For the small molecules anthracene and rhodamine 6G, the wire was cut and affixed to a metal target using double-sided conductive tape and analyzed by LDI using a commercial laser desorption time-of-flight mass spectrometer. Approximately 100 fg of material was ablated from each of the 1 μm ablation spots and transferred with approximately 3% efficiency. For larger polypeptide molecules angiotensin II and bovine insulin, the captured material was dissolved in saturated matrix solution and deposited on a target for MALDI analysis.
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