Assessing the linear response of ITC (dynamic ion transmission control) is an easy way to determine whether you should clean your QJet ion guide and IQ0 lens. A clean rod set and lens should give a linear response when ramping the ITC parameter and the ratio of 132 to 829 should remain the same.
Here is a simple infusion test using Tuning Solution (SCIEX P/N 4457953), to determine whether front end system cleaning is required. It is recommended to use the SCIEX Concentrated Powder Instrument Cleaner (P/N 5045687) follow the cleaning protocol for best results, please reach out to your local service engineer for training.
- Build the TOF MS method as described above in Table 1.
- Infuse the Tuning Solution:
- Flow rate of 5 µL/min for the DuoSpray Source
- Flow rate of 0.5 µL/min for the NanoSpray Source
- Collect data for 1 min under each different ITC condition. Remember to change the ITC value in Parameter Settings.
- After acquisition, right click and select Open File. Open a single spectrum by double clicking on the TIC.
- Zoom in on the 829 peak and select the full spectral peak width then right click and select Extract Ions (Use Range). This will ensure the full spectral peak is used in the computation of the XIC.
- Zoom in on the 132 peak and select the full spectral peak width then right click and select Extract Ions (Use Range). This will ensure the full spectral peak is used in the computation of the XIC.
- Record the XIC value of 829 and 132 at each ITC setting. The m/z 829 peak should show a linear response, the ratio of m/z 132 to m/z 829 should remain constant with the 132 >x1.5 than that of 829.
- Ratio of m/z 132 to 829 should remain constant throughout the dynamic range of the instrument. Relative loss of the 132 ion at low ITC values could indicate that QJet, IQ0 and/or Q0 are dirty.
- A ratio of m/z 132 to 829 <1.5 to 1 at ITC=0 is typically casued by dirty QJet, IQ0 and/or Q0.
- The m/z 829 peak on the TripleTOF 6600 system may reach saturation at the highest ITC setting, which is OK.
- On the TripleTOF 5600+ system, the signal will be linear up to an XIC of 1.8e5.
- On the TripleTOF 6600 system, the signal will be linear up to an XIC of 1.4e6.