The development of charge detection-quadrupole ion trap mass spectrometry driven by rectangular and triangular waves.

In this article, the charge detection quadrupole mass spectrometry (CD-ITMS) driven by rectangular and triangular waveforms (rect-CD-ITMS and tri-CD-ITMS) was developed for the characterization of microparticles. Since the frequency scan of rectangular and triangular waveform could be realized easier than that of sinusoidal waveform, this research intends to provide simpler operation modes for CD-ITMS. In order to demonstrate the feasibility of rect-CD-ITMS and tri-CD-ITMS, the discharge onset voltage, ejection point of analyzed particles, and the achieved mass resolution were analyzed and compared with the case in conventional sinusoidal CD-ITMS (sin-CD-ITMS). The results indicated that the rect-CD-ITMS and tri-CD-ITMS can work well for the mass measurement of microparticles by using frequency scan. Identical mass resolutions were achieved under the same root mean square (RMS) voltage of different waveforms. The mass resolution was further improved by increasing the applied voltage and signal-to-noise ratio (S/N) of charge detector. Moreover, the rect-CD-ITMS and tri-CD-ITMS were applied to characterize red blood cells (RBCs). According to the obtained mean masses and mass distributions, normal and anemic RBCs were distinguished successfully.