Scaled Kendrick Mass Defect Analysis for Improved Visualization of Atmospheric Mass Spectral Data Journal Article uri icon



  • Abstract. Mass spectrometry is an important analytical technique within the field of atmospheric chemistry. Owing to advances in instrumentation, particularly with regards to mass resolving power and instrument response factors (sensitivities), hundreds of different mass-to-charge (m/z) signals are routinely measured. This large number of detected ions creates challenges for data visualization. Furthermore, assignment of chemical formulas to these ions is time-consuming and increases in difficulty at the higher m/z ranges. We present a technique called scaled Kendrick mass defect (SKMD) analysis to facilitate the visualization and peak identification processes for typical atmospheric organic (and to some extent inorganic) compounds. SKMD is related to the previously proposed resolution enhanced Kendrick mass defect (REKMD). SKMD introduces a tunable integer scaling factor into the mass defect equation that effectively contracts or expands the mass scale. The SKMD transformation maintains the horizontal alignment of ion series related by integer multiples of the chosen base unit that is characteristic of Kendrick mass defect analysis. However, the tunable integer acts to alter the mass defect spacing between different homologue ion series. As a result, the entire mass defect range (-0.5 to 0.5) is more effectively used simplifying data visualization and facilitating chemical formula assignment. We describe the mechanism of this transformation and discuss base unit and scaling factor selections appropriate for compounds typically found in atmospheric measurements. We present an open-source graphical user interface (GUI) for calculating and visualizing SKMD analysis results within the Igor Pro Environment.;

publication date

  • December 9, 2022

has restriction

  • green

Date in CU Experts

  • December 20, 2022 8:12 AM

Full Author List

  • Alton MW; Stark H; Canagaratna MR; Browne EC

author count

  • 4

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