Organic Acid Quantitation in Mouse Muscle by Ion Chromatography-Mass Spectrometry with Isotopically Labeled Standards

Organic acids (OAs) are important metabolites that play an essential role in an array of energy metabolism pathways (e.g., glycolysis and tricarboxylic acid cycle). In this application note, a targeted IC-MS method using stable isotope-labeled standards (SIS) was used to quantify a panel of polar OAs in mouse muscle. The SIS OAs served as internal standards for enhanced precision and accuracy of OA measurements. Statistically significant quantitative differences were observed for four OAs in the quadricep muscle of sedentary and fatigued mice. Overall, this study demonstrated the ability of IC-MS with stable isotope-labeled OAs to separate and quantify a collection of low molecular weight polar metabolites that are difficult to analyze by other techniques.