Rapid and reliable quantitation of amino acids and myo-inositol in mouse brain by high performance liquid chromatography and tandem mass spectrometry

Amino acids and myo-inositol have long been proposed as putative biomarkers for neurodegenerative diseases. Accurate measures and stability have precluded their selective use. To this end, a sensitive liquid chromatography tandem mass spectrometry (LC–MS/MS) method based on multiple reaction monitoring was developed to simultaneously quantify glutamine, glutamate, γ-aminobutyric acid (GABA), aspartic acid, N-acetyl aspartic acid, taurine, choline, creatine, phosphocholine and myo-inositol in mouse brain by methanol extractions. Chromatography was performed using a hydrophilic interaction chromatography silica column within in a total run time of 15 min. The validated method is selective, sensitive, accurate, and precise. The method has a limit of quantification ranging from 2.5 to 20 ng/ml for a range of analytes and a dynamic range from 2.5–20 to 500–4000 ng/ml. This LC–MS/MS method was validated for biomarker discovery in models of human neurological disorders.

► A sensitive, selective, and simple LC–MS/MS method using HILIC was validated for the quantification of nine AAs and MI in mouse brain. ► One step methanol–protein precipitation was used for sample extraction. ► Method validation was performed in the range of 2.5–20 to 500–2000 ng/ml to ensure the simultaneous quantification of all analytes of interest.