title: Simple and inexpensive flow L-glutamate determination using pumpkin tissue.
abstract: This work refers to a very easy to implementate flow injection system with potentiometric detection for l-glutamate determination in food samples. The proposed procedure is based on measurement of carbon dioxide produced by decarboxylation of l-glutamate catalyzed by l-glutamate decarboxylase (E.C. 4.1.1.1.5) from Cucurbita maxima (pumpkin). The FI potentiometric system includes an enzymatic reactor with a length of 8 cm and thickness of 5 mm packed with 200 mg of a C. maxima outer layer cut in to small pieces. The proposed procedure allowed l-glutamate determinations in the concentration interval of 10-100 mmol L(-1) for an injected sample volume of 50 microL. A phosphate buffer (0.1 mol L(-1), pH 5.5) solution flowing at 1.4 mL min(-1) was used as the carrier solution in the system. The results obtained in the analysis of food samples revealed a relative error lower than 5% when compared with those provided by the spectrophometric reference procedure. The immobilized reactor retained its initial activity for 21 days. It was possible to measure 40 samples/h with the flow system proposed.
authors: Biochemistry Department, Laboratory of Immunopathology Keizo Asami (LIKA), UFPE-50670-901-Recife-PE, Brazil.
authors: Nicácio J M
authors: NJ
authors: Arruda
authors: José L L
authors: JL
authors: Filho
authors: Maria C B S M
authors: MC
authors: Montenegro
authors: Alberto N
authors: AN
authors: Araújo
authors: Valdinete L
authors: VL
authors: Silva
mesh_terms: D028464:Cucurbita / Q000201:enzymology*; D017022:Flow Injection Analysis / Q000295:instrumentation / Q000379:methods*; D005504:Food Analysis / Q000379:methods*; D005968:Glutamate Decarboxylase / Q000378:metabolism; D018698:Glutamic Acid / Q000032:analysis*; D007202:Indicators and Reagents; D007700:Kinetics; D011199:Potentiometry
chemical_list: D007202:Indicators and Reagents; D018698:Glutamic Acid; D005968:Glutamate Decarboxylase