Simple correction improving long‐term reproducibility of HPLC–MS

Abstract

SummarySignal intensities in long series of HPLC-MS experiments often vary, which decrease reproducibility and may cause bias in the results. It was found that the sensitivity of various components change differently; in our case variability is in the order of 20-40%; and it is most likely due to changing conditions in ESI ionization. The most often used intensity correction methods do not take this effect into account. The change in signal intensities (peak areas) can be well described by a polynomial function; we found that a 4 th order polynomial is most often suitable. We suggest a simple correction algorithm based on polynomial fitting. When the experiments were inherently well reproducible, this correction improved reproducibility from 12% to 3% (on average for various components). When random errors were larger, this improvement was less significant (15% to 12% in nano-ESI), but nevertheless essential in order to avoid possible bias in the results.

High sensitivity proteomics of prostate cancer tissue microarrays to discriminate between healthy and cancerous tissue

“…or temporal changes in ESI spray conditions)[23]. In order to improve the reliability of analysis, these outliers should be left out.…”