Potentiometric determination of urea by sequential injection using Jack bean meal crude extract as a source of urease

• Type: Article in International Scientific Journal
• Date: 2000

Authors

Silva, FV (Author) Other; Nogueira, ARA (Author) Other; Souza, GB (Author) Other; Reis, BF (Author) Other; Araujo, AN (Author) FFUP; Montenegro, MCMBS (Author) Other; Lima, JLFC (Author) FFUP

Journal

Title: Talanta

Vol. 53

Pages: 331-336

ISSN: 0039-9140

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 23 Citations

Scopus - 25 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-000-YPA

DOI: 10.1016/s0039-9140(00)00490-2

Abstract (EN): A sequential injection system was proposed to accomplish the potentiometric determination of urea. This procedure used an ammonium tubular selective electrode to assess ammonium concentration produced by enzymatic hydrolysis of urea from Jack bean meal (Canavalia ensiformis DC) crude extract. A gaseous diffusion device was coupled to the flow set-up allowing on-line sampling and suitable selectivity for determinations. A detection limit of 6.0 x 10(-4) mol urea l(-1), a relative standard deviation of 1.9% (n = 10) and a sampling rate of 20 samples h(-1) were observed when 172 Sumner units (SU) of urease and 900 mul of sample were used. Results agreeing with a comparative method were obtained by the proposed procedure and the use of the crude extract solution combined with the sequential injection approach improved the performance, producing reproducible results and low costs in comparison with procedures using commercial enzymes.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6