Nondestructive ion trap mass analysis at high pressure.

A method for performing nondestructive ion trap mass analysis at high pressures (>1 mTorr) has been developed using image current measurement with constant dipolar excitation. Instead of monitoring the ion secular motion, a harmonic of the ion motion was used for narrow band image current measurement followed by Fourier Transform. The capability of this technique has been demonstrated with mass analysis using a single measurement at pressures of 10 mTorr or higher. Methods for mixture analysis and tandem mass spectrometry have also been developed for nondestructive mass analysis.