RESUMEN
A one-step analysis method was developed for four types of amino acids using a microfluidic paper-based analytical device fabricated from chromatography filtration paper and laminate films. Aminoacyl-tRNA synthetase was used to detect each amino acid. The obtained laminated paper-based analytical device (LPAD) contained four enzymatic reaction areas. Colorimetric detection was performed based on the molybdenum blue reaction. A model method for the simple, easy, and simultaneous detection of several amino acid concentrations was suggested, in contrast to the conventional methods such as HPLC or LC-MS. The method provided a selective quantification at the ranges of 3.6-100 µM for tryptophan, 10.1-100 µM for glycine, 5.9-100 µM for histidine and 5.6-100 µM for lysine with a detection limit of 1.1 µM, 3.3 µM, 1.9 µM and 1.8 µM, respectively. LPAD fabrication was considerably simple, and the subsequent detection process was easy and required a short period of time (within 15 min).