Linear correction of the amount of spiked di14:1 phosphatidylcholine with those determined with mass spectrometry. Samples spiked with 10 different amounts of di14:1 phosphatidylcholine (PC) into a lipid extract of mouse myocardium (see text) were prepared in duplicates. The amount of the spiked di14:1 PC in each prepared sample was determined with either full-MS analysis in triplicates (Panel A), NLS183.1 (Panel B), or NLS189.1 in comparison to the amount of an endogenous PC species (i.e., 16:0–22:6 PC at m/z 812.6 as a lithium adduct), which was pre-determined. Each data point represents mean ± SD from the analysis of either 6 full MS spectra, 2 NLS183.1 spectra, or 2 NLS189.1 spectra of each spiked amount of di14:1 PC. Most of the error bars of the data points are within the symbols.