Mass spectrum selectivity-based chromatogram baseline-shift elimination and its application in metabonomics of liver toxicity

•A method of chromatogram baseline-shift elimination is proposed.•Urine samples data is generated from acetaminophen and CCl4-treated rats by UPLC–MS.•The method could obtain the baseline with heteroscedastic noise.•Baseline-shift has an effect on metabobomics model and evaluation of drug toxicity.

Based on high selectivity of mass spectrum, a method of chromatogram baseline-shift elimination was proposed and applied to study the interference of the baseline-shift on the metabonomics of liver toxicity caused by acetaminophen (APAP) and carbon tetrachloride (CCl4), and the metabonomics model-based evaluation of drug toxicity. The chromatogram baseline obtained by this method was true in all ranges of the retention time, including the ranges of chromatographic peaks. Besides, it could express the baseline-shift with the heteroscedastic noise, which was usually contained in the chromatographic peak and grew with the signal intensity of the peak. The metabonomics models of liver toxicity were built according to total ion chromatograms of urine samples from APAP, CCl4 and normal groups, whose baseline-shift was eliminated by this method. The result showed that baseline-shift would lead to a reduction of the evaluated toxicity and then may result in a wrong evaluation of drug toxicity.