A rapid, sensitive, and widely applicable method for the simultaneous quantitative analysis of 20 underivatized amino acids in different biological matrices, including serum, plasma, and tissue homogenates, using ultra high performance liquid chromatography with tandem mass spectrometry was developed and validated.Only 4 μL of serum, plasma, or tissue homogenate was extracted with 996 μL of solution (1.7 mM ammonium formate in 85% acetonitrile containing 0.1% formic acid) containing 100 ng/mL phenylalanine-d5 as an internal standard without any further derivatization step. In addition, the matrix effects were small because a large volume of extraction solution was used. The total run time including reequilibration was 13 min. The results of linearity, accuracy, repeatability, precision, limits of detection, limits of quantification, and sample stability were sufficient to allow the measurement of the amino acids in different biological matrices. We conclude that our method is rapid, sensitive, and widely applicable and represents an improvement over other currently available technologies.
K E Y W O R D Samino acids, biological matrices, tandem mass spectrometry, ultra high performance liquid chromatography Article Related Abbreviations: CE, collision energy; CV, cone voltage; IS, internal standard; MRM, multiple reaction monitoring. selective methods for the identification and quantification of amino acids is important.Amino acids have a variety of structures and physicochemical properties; therefore, quantitative methods must be robust, sensitive, and amenable to a number of different media. Recently, several technologies have been developed for the analysis of amino acids, including GC-MS [7,8], , stable isotope labelling [14][15][16], and absorbance methodologies [17]. Because of the complexity of media such as urine, plasma, and cerebrospinal fluid as well as the diversity of amino acid properties, methods for quantifying amino acids are generally complex and require multiple clean-up steps to improve the sensitivity and selectivity. For