A system of high performance liquid chromatography (HPLC) was used for the development and validation of efficient method for quantitative determination of three aminoacids involved in the inherited metabolic disease Branched-Chain Ketoaciduria (BCK), also called maple syrup urine disease. The analytical conditions were selected in order to obtain baseline separation profiles of the amino acids known to be altered in blood plasma of BCK patients, namely L-valine, L-isoleucine, and L-leucine. Most accurate data were obtained using HPLC/diode detector. As the analytes do not have chromophore groups, they were pre-derivatized with o-phthaldialdehyde (OPA), yielding an unsaturated adduct, making thus possible the detection of amino acids. The validation was conducted according to National Health Surveillance Agency (ANVISA) and Guidance for Industry (Bioanalytical Method Validation) United States Food and Drug Administration (U.S. FDA). The results were satisfactory, with high sensitivity, good linearity, precision and accuracy, limit of detection and quantification, all within the established parameters for bioanalytical methods, showing its applicability and low cost compared to other existing techniques such as sequential mass spectrometry. For the three amino acids, L-valine, L-isoleucine and L-leucine, the detection limits (LOD) found were: 1.61, 1.84 and 1.88 mmol L- 1 and the quantification limits (LOQ) 4.37, 6.13 and 6.27 mmol L- 1, respectively.
high performance liquid chromatography; maple syrup urine disease; isoleucinose; rare diseases; metabolism; inborn error; branched chain aminoacids; α-ketoacids
