1,2,3-Tritricosanoyl glycerol, a triacylglycerol containing tricosanoic acid at the sn-1, sn-2, and sn-3 positions, serves as an internal standard for the quantification of fatty acids within the triglyceride component of human aortic endothelial cells (HAECs) cultured in media supplemented with stearic and/or oleic acid.