16:0 Phosphatidylpropanol or 1,2-dipalmitoyl-sn-glycero-3-phosphopropanol may be used as an internal standard in ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) to evaluate its matrix effect in blood samples for the validation of phosphatidylethanol (PEth). It may also be used as an internal standard for the quantification of PEth using liquid chromatography-mass spectrometry (LC-MS) in human blood.