LCT Premier: Positive/Negative Ionization Switching

The Waters LCT Premier Mass Spectrometer is the highest performance bench-top orthogonal acceleration time-of-flight (oa-Tof) LC-MS System available today. The innovative design and hardware enhancements to our original LCT Mass Spectrometer’s design provide the user with the capabilities of positive/negative source ionisation capabilities on a per-injection basis, but even faster than before. With new detector and electronic components, the instrument can switch from positive to negative ion, or vice versa, in a minimum of 200 milliseconds, or 300 milliseconds for exact mass measurement.

Benefits

Positive/negative ionization switching provides the user with the capability of analyzing samples during LC-MS experiments without needing to know a compound’s particular ionization mode

The Waters LCT Premier Mass Spectrometer is the highest performance bench-top orthogonal acceleration time-of-flight (oa-Tof) LC-MS System available today. The innovative design and hardware enhancements to our original LCT Mass Spectrometer’s design provide the user with the capabilities of positive/negative source ionisation capabilities on a per-injection basis, but even faster than before. With new detector and electronic components, the instrument can switch from positive to negative ion, or vice versa, in a minimum of 200 milliseconds, or 300 milliseconds for exact mass measurement. 

Positive/negative ionization switching provides the user with the capability of analyzing samples during LC-MS experiments without needing to know a compound’s particular ionisation mode. This is ideal for screening applications or when multi-component mixtures are being analyzed. Even at 300 milliseconds switching time, exact mass measurements can be carried out - and all this during LC time scales.

Figure 1 shows a mass spectrum of raffinose analysed with positive/negative electrospray ionization. With 300 milliseconds switching on the LCT Premier, the exact mass measurements are within 3 ppm. The lower spectrum shows the ES+ [M+Na]⁺ ion of raffinose and the upper spectrum shows the ES- [M-H]^- ion. Both exact mass measurements obtained from the single LC-MS analysis are within 2 ppm of actual mass.

Figure 2 shows another example of positive/negative ionisation switching and its usefulness for complex mixture analysis. Figure 2 shows the LC-MS chromatograms for the ES+, ES-, and diode array trace for a natural product extract. Figure 3a and 3b shows the simultaneous exact mass spectra obtained for both peak A (iso-orientin) and peak B (kaempforol-3-rutinoside) from the same injection. All exact mass measurements are within 2 ppm of actual providing highly specific answers. 

LCT Premier: oa-Tof providing simultaneous exact mass measured positive/negative ionization.