Date: | 09/29/2017 |
Categories: | QTRAP systems , Triple Quad systems |
For research use only. Not for use in diagnostic procedures. |
Issue Description
Over a period of several months, you may notice a decrease in sensitivity when using the same acquisition method. One cause can be that the detector voltage (CEM) requires adjustment. The detector in a mass spectrometer will degrade over time, and the detector voltage will need to be increased on a routine basis.
Resolution
You should optimize the value set for the detector parameter (CEM) regularly to make sure that you are getting the best performance from your instrument. Contact Service regarding the frequency for your system.
The optimization procedure is quick and easy to do yourself. It is performed using the PPG tuning solution in positive ion mode (refer to Table 1 for the appropriate tuning solution to use).
Mass Spectrometer |
Positive PPG Tuning Solution* |
3200, 4000, 5000 Series Systems |
POS PPG, 2e-6 M |
3500, 4500 Series Systems |
POS PPG, 2e-6 M |
5500, 6500 Series Systems |
POS PPG, 2e-7 M |
Table 1: PPG Tuning Solution
Note: for TOF instruments, the detector parameter can be automatically optimized using the Instrument Optimization wizard.
Section 1: Analyst® Software and Hardware Setup
IMPORTANT: The API Instrument project contains all the necessary PPG methods used to optimize the detector parameter for the instrument. These methods should not be changed. It is highly recommended to maintain a backup of the API Instrument project.
Section 2: Detector (CEM) Parameter Optimization
Instrument |
Detector Increment |
Recommended % Intensity Increase |
2000, QTrap, 3200 |
50 |
20-40% |
3000, 4000, 5000 |
100 |
20-40% |
3500, 4500, 5500, 6500 |
50 |
30% or less (10-30% suggested) |
Table 2: Instrument Detector Increments and Recommended % Intensity Increases
% Intensity Increase = ((2nd Intensity-1st Intensity) / 1st Intensity ) x 100
For other possible causes of low sensitivity on your instrument, visit SCIEXUniversity and view this eLearning module:
SCIEX Triple Quad™ and QTRAP® Instrument Maintenance and Troubleshooting Guide.
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