Deconvolution and compensation of MS interferences

For many gas species (e.g., He, Ar, Kr, N2, O2, CO2) the partial pressures measured with the miniRUEDI can usually be calibrated by simple peak-height comparison relative to ambient air or gas standard with well known partial pressures. However, depending on the composition of the analysed gases, the ion currents measured at certain m/z ratios may result from overlapping ion currents of multiple species (for example CH4, O2 and N2 at m/z=15 and 16; or Ne, Ar and H2O at m/z=20).

We developed a method that extends the miniRUEDI peak-height comparison in order to resolve such overlap interferences. The method uses spectral deconvolution and was incorporated in the ruediPy software toolbox. The deconvolution method substantially improves the analytical accuracy in situations where mass-spectrometric interferences cannot be avoided.

Full details are availalble in the original publication: M.S. Brennwald, Y. Tomonaga, R. Kipfer: Deconvolution and compensation of mass spectrometric overlap interferences with the miniRUEDI portable mass spectrometer, MethodsX, 2020, doi: 10.1016/j.mex.2020.101038

Running on Batteries

We frequently get asked how to run the miniRUEDI on batteries for field work at remote locations with no mains power.

Here are the basics to run the miniRUEDI on batteries:

  • The miniRUEDI runs on a voltage of 24 V.
  • The miniRUEDI draws about 2 A current during normal operation, and up to about 5 A or slightly more during startup of the pumps.
  • You need a fuse. Batteries do not like short circuits or similar mishaps. A 10 A rating should be fine.
  • Unplug the 24 V connections of the main power supply unit in the miniRUEDI, and connect the batteries to the miniRUEDI instead.

There are many ways to set up a battery power supply, but here is a simple setup that uses two simple «12 V car batteries»:

The capacity of the batteries determines how long they will be able to supply power to the miniRUEDI. Two of the typical «12 V car batteries» with a capacity rating of 60 Ah may last up to a full day before they need to be recharged.