Influence of polarity mode switching and standby times on signal stability and detection of aspirated droplet signatures in electrospray mass spectrometry
IF 1.6 3区 化学Q3 PHYSICS, ATOMIC, MOLECULAR & CHEMICAL
Chris Heintz, Lisa Schnödewind, Oliver Braubach, Hendrik Kersten, Thorsten Benter, Walter Wißdorf
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引用次数: 0
Abstract
Electrospray ionization plays a central role in modern analytical chemistry. It is often used in combination with an HPLC system and is able to transfer large molecules, such as proteins and complexes, into the gas phase. A liquid solution containing the analyte is sprayed in a strong electric field. Charged droplets generated by this process release the analyte molecules which can ultimately be analyzed by the mass spectrometer system. However, the exact mechanisms of droplet generation and ion release are still not fully understood and are under investigation. Recent literature puts the focus on droplet disintegration and shows that the analyte ions are not exclusively released from the droplets within the ionization chamber but rather in the whole mass spectrometer system. Previous experiments allow the direct observation of the signatures of fragmented droplets within the analyzer region of a time-of-flight mass spectrometer: An oscilloscope was connected to a secondary electron multiplier which serves as an auxiliary ion detector, located downstream of the orthogonal acceleration stage of a time-of-flight mass spectrometer. The oscilloscope is thus able to monitor the time-resolved ion current in the mass analyzer region. Pulses of extraordinarily high ion currents are observable here which are attributed to aspirated charged droplets.
This work provides insights into long-term experiments with this experimental setup. There is a focus on signal stability, in the presence of such droplet signatures. It is apparent that the standby time of the instrument between individual measurements and the time since a switch of the polarity mode, has a significant influence on the signal stability. There are also indications that the observations of droplet signatures and the MS signal stability are correlated.
期刊介绍:
The journal invites papers that advance the field of mass spectrometry by exploring fundamental aspects of ion processes using both the experimental and theoretical approaches, developing new instrumentation and experimental strategies for chemical analysis using mass spectrometry, developing new computational strategies for data interpretation and integration, reporting new applications of mass spectrometry and hyphenated techniques in biology, chemistry, geology, and physics.
Papers, in which standard mass spectrometry techniques are used for analysis will not be considered.
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