Phenylalanine and tyrosine in serum and eluates from dried blood spots as determined by reversed-phase liquid chromatography
Rudy, J.L.; Rutledge, J.C.; Lewis, S.L.
Clinical Chemistry 33(7): 1152-1154
1987
ISSN/ISBN: 0009-9147 PMID: 3594842 Document Number: 287456
We have developed a reversed-phase liquid-chromatographic procedure for simultaneously determining phenylalanine and tyrosine in serum and eluates of dried blood spots. Batch derivatization with phenylisothiocyanate and a 10-min linear gradient chromatographic assay with ultraviolet absorbance detection provide rapid sample throughput. Interrun precision (CV) is less than 12%; analytical recovery (from blood spot samples) exceeds 85%. Results for patients' samples correlate well with those from an amino acid analyzer and we encountered no apparent interferences. The speed and specificity of this assay facilitate the rapid diagnosis and monitoring of patients with phenylketonuria.