A Noise and Background Reduction Method for Component Detection in Liquid Chromatography/Mass Spectrometry

The combination of liquid chromatography with mass spectrometry, particularly using electrospray as an ionization method, can result in chromatograms with a high level of background and noise. The use of background subtraction techniques or the Biller−Biemann algorithm to reduce this problem was of limited success. A variable selection procedure was developed that selects mass chromatograms with low noise and low background; these mass chromatograms are then combined to form a reduced total ion chromatogram (TIC) trace. This is achieved by calculating a “similarity index” between each original mass chromatogram and its smoothed and mean-subtracted version. It is further shown that it is possible to reduce the number of mass chromatograms by more than an order of magnitude without losing chemically significant information. The process results in significantly improved chromatograms and a significant reduction in data analysis times for liquid chromatography/mass spectrometry. The approach is named component detection algorithm (CODA).