Effect of the Laser Pulse Width in MALDI-2: A Comparative Study of Picosecond versus Nanosecond Wide Pulses for Laser Postionization
| Autor: | Alexander Potthoff, Olaf Minte, Klaus Dreisewerd, Jens Soltwisch |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Journal of the American Society for Mass Spectrometry. 33:315-321 |
| ISSN: | 1879-1123 1044-0305 |
| Popis: | MALDI-2 is a recently introduced technique for postionization (PI) in matrix-assisted laser desorption/ionization (MALDI). It is based on an initial photoionization of neutrally desorbed matrix molecules and subsequent charge-transfer reactions in a fine vacuum or atmospheric pressure ion source. MALDI-2 significantly increases the ion yields for numerous classes of analytes, including lipids, glycans, and a range of pharmaceuticals. To obtain insights into the ionization mechanisms underlying the primary step of PI in MALDI-2, we here conducted a set of experiments with two lasers at 266 nm wavelength and pulse durations of 28 ps and 6 ns, respectively, on a modified orthogonal-extracting time-of-flight mass spectrometer (QTOF, Synapt). 2,5-Dihydroxybenzoic acid (DHB) and 2,5-dihydroxyacetophenone (DHAP) were investigated as MALDI matrices in the positive-ion mode with standardized lipid samples. Analyte- and matrix-derived ion signals were recorded as a function of PI laser pulse energies. The ion signal intensity displays a quadratic dependency on PI-laser pulse energy for low to moderate intensities of up to ∼10 |
| Databáze: | OpenAIRE |
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