Liquid chromatography/tandem mass spectrometry offers great potential for quantitative proteomics, but optimal workflows and system configurations still needs to be established. In this study we developed, validated and compared three procedures for absolute quantitation of cardiac troponin T (cTnT) using microflow LC/MS or chip-­‐based nanospray source with direct injection or preconcentration nanoflow LC/MS. Troponin T content was evaluated in hearts of C57BL/6 and ApoE/LDLR double knock-­‐out mice.