Figure 4

Coefficients of variance for individual peaks in liver repeatability study. Each peak detected is shown in the two dimensional plot of m/z vs. retention time plot, with the color corresponding to the coefficient of variance. The NOMIS method performs notably better in its ability to reduce the variability across the full spectrum. The 3STD method performs particularly poorly for higher retention times, where the normalization is based on triacylglycerol standard found to be highly variable (Table 1).