Sistema em fluxo para determinação espectrofotométrica de uréia em plasma de sangue animal empregando leguminosa como fonte natural da enzima urease

• Main Authors: Luca Gilmara C., Reis Boaventura F.
• Format: Article
• Language: English
• Published: Sociedade Brasileira de Química 2001-01-01
• Series: Química Nova
• Subjects: urea determination; leguminous plant urease source; flow analysis; animal blood plasma
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-40422001000200008

A spectrophotometric flow injection analysis (FIA) procedure employing natural urease enzyme source for the determination of urea in animal blood plasma was developed. Among leguminous plants used in the Brazilian agriculture, the Cajanus cajan specie was selected as urease source considering its efficiency and availability. A minicolumn was filled with leguminous fragments and coupled to the FIA manifold, where urea was on-line converted to ammonium ions and subsequently it was quantified by spectrophotometry. The system was employed to determine urea in animal plasma samples without any prior treatment. Accuracy was assessed by comparison results with those obtained employing the official procedure and no significant difference at 90 % confidence level was observed. Other profitable features such as an analytical throughput of 30 determinations per hour, a reagent consumption of 19.2 mg sodium salicylate, 0.5 mg sodium hipochloride and a relative standard deviation of 1.4 % (n= 12) were also obtained.