TY - JOUR A1 - Stindt, Arne A1 - Warschat, Carsten A1 - Bierstedt, Andreas A1 - Panne, Ulrich A1 - Riedel, Jens T1 - Characterisation of an inexpensive sonic spray ionisation source using laser induced fluorescence imaging and mass spectrometry JF - European journal of mass spectrometry N2 - A commercially available airbrush gun as a new source for spray ionization is presented. It is best operated employing moderate stagnation pressures, resulting in a sonic gas flow. A mass spectrometric investigation on the amino acid lysine and several peptides reveals that this inexpensive approach results in reproducible mass spectra. The ion patterns strongly resemble the results from other studies obtained with custom made sonic spray vaporizers. The patterns as well resemble the mass spectra recorded with electrospray devices. For a better understanding of the vaporization process, the mass spectrometry experiments are accompanied by laser induced fluorescence experiments. Inverse Abel transform of the obtained fluorescence maps allows the determination of the full 3D distribution of the spray cone. Furthermore, via exploitation of the solvatochromism of the used dye the solvation state distribution can be visualized. In addition, expansion parameters like droplet size and velocity are obtained by laser stroboscopy. The experiments demonstrate that the analyte is hardly desolvated throughout the expansion. This indicates a subsequent vaporization of the residual solvent in the intermediate pressure region of the mass spectrometer. KW - Sonic spray ionization KW - Mass spectrometry KW - Solvatochromism KW - Inverse Abel Transform KW - Sonic spray KW - Airbrush KW - Laser induced fluorescence PY - 2014 DO - https://doi.org/10.1255/ejms.1242 SN - 1469-0667 SN - 1356-1049 SN - 1365-0718 VL - 20 IS - 1 SP - 21 EP - 29 PB - IM Publications CY - Chichester AN - OPUS4-30403 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bierstedt, Andreas A1 - Stindt, Arne A1 - Warschat, Carsten A1 - Panne, Ulrich A1 - Riedel, Jens T1 - High repetition rate atmospheric pressure matrix-assisted laser desorption/ionization in combination with liquid matrices JF - European journal of mass spectrometry N2 - One major drawback of matrix-assisted laser desorption/ionization (MALDI) is still the relatively poor pulse-to-pulse reproducibility of the signal intensity. This problem, caused by insufficient homogeneity in the matrix/analyte co-crystallization, is usually circumvented by averaging the detected ion intensity over several shots. However, during the consecutive laser pulses, the applied matrix gets depleted and only a number of subsequent experiments can be done on the same sample spot. In order to achieve the desired long-term stability in combination with a sufficient pulse-to-pulse reproducibility, recently liquid MALDI matrices have been introduced. This contribution demonstrates the promising combination of liquid matrices with high repetition rate lasers for atmospheric pressure MALDI (AP-MALDI). To demonstrate the robustness of the new approach, two different kinds of liquid matrices were used in combination with both a typical flashlamp pumped 15 Hz laser and a diode pumped solid state laser operated at 5 kHz. The latter showed a stable ion signal over more than 3,500,000 consecutive laser pulses. KW - AP-MALDI KW - Liquid matrix KW - High repetition rate KW - Ionic liquid KW - DPSS laser PY - 2014 DO - https://doi.org/10.1255/ejms.1292 SN - 1469-0667 SN - 1356-1049 SN - 1365-0718 VL - 20 IS - 5 SP - 367 EP - 374 PB - IM Publications CY - Chichester AN - OPUS4-32510 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -