Journal of the Brazilian Chemical Society
On-line version ISSN 1678-4790
BORGES, Eduardo P. and REIS, Boaventura F.. An enzymatic flow-injection procedure with chemiluminescence detection for on-site determination of L-alanine in synthesis process. J. Braz. Chem. Soc. [online]. 2005, vol.16, n.6a, pp. 1226-1232. ISSN 1678-4790. http://dx.doi.org/10.1590/S0103-50532005000700021.
In this work an automatic flow procedure for L-alanine determination in the synthesis medium without a prior sample treatment is described. The method was based on oxidation of L-alanine by L-amino acid oxidize followed by the reaction of the H2O2 with luminol and chemiluminescence detection. In order to overcome the severe alkaline condition of the synthesis medium, a zone sampling strategy was employed for automatic sample dilution and pH adjustment. The procedure allows L-alanine determination in the range of 0.5 to 25.0 mmol L-1, a limit of detection of 0.08 mmol L-1 and a variation coefficient lower than 4% (n = 10). Other advantageous feature such as a sampling throughput of 44 determination per hour and low reagent consumption, 0.2 mg luminol and 16.4 mg hexacinoferrate(III) per determination, respectively, were also achieved.
Keywords : flow analysis; automation; chemiluminescence; amino acid; L-alanine.