Development of an Analytical Method For Determination of Urine 3-Phenylpyruvic Acid Based on Liquid-Liquid Extraction and LC-MS/MS

Abstract

Aim: The aim of this study is to develop a rapid, precise, specific LC MS MS method for the determination of 3-phenylpyruvic acid, which has an important place in the diagnosis of phenylketonuria, a metabolic disease resulting from Phenylalanine Hydroxylase Enzyme deficiency.
 Materials and Methods : Analytical measurements were made with Acqutiy UPLC MS MS (Waters Xevo TQD). The chromatographic separation was operated on an Acquity UPLC Phenyl column (50 mm × 2.1 mm, 1.7 μm) with gradient elutionusing 0.1% formic acid containing water and methanol as the mobile phase. Within the scope of the study, firstly, sample preparation steps were focused and dispersive liquid liquid extraction and traditional liquid extraction methods were examined. The best results were obtained in the conventional liquid liquid extraction method, in which dichloromethane was used as the extraction solvent. In addition, in this study, trans cinnamic acid was tested as an internal standard for the determination of 3-phenylpyruvic acid and passed the validation steps.
 Results : The linear range of the developed LC MS MS method was found to be between 0.009-5 M, while the detection limit was found to be 0.001 M. Intraday repeatability was below 7% for 3 levels, and interday repeatability was below 10%. In the recovery trial, which showed the accuracy of the method, the results in the urine sample for 3 levels were in the range of 97%-103%, and there was no significant ion suppression in the matrix effect trial, which showed how clean the final matrix obtained as a result of the sample preparation steps was.
 Conclusion: As a result, a fast, inexpensive LC MS MS method has been developed for 3-Phenylpyruvic acid.