Calibration exercises are essential for determining the accuracy of instruments. We performed calibrations on a NO₃¯ ToFCIMS instrument to determine its sensitivity and linearity for detecting various organic compounds. Our findings revealed significant variability, over several orders of magnitude, in the calibration factors obtained. The results suggest that relying on a single calibration factor from H₂SO₄ for the quantification of all compounds detected by this technique is not appropriate.