A multicommuted system using bacterial cellulose for urease immobilization and copper (II)-MOF colorimetric sensor for urea spectrophotometric determination in milk

• Published in: Food chemistry Vol. 460; no. Pt 1; p. 140454
• Main Authors: Rodrigues, Julyana C., Bezerra, Caio S., Lima, Lidiane M.A., Neves, Danielle D., Paim, Ana Paula S., Silva, Wagner E., Lavorante, André F.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.12.2024
• Subjects: Adulterant; Animals; Bacteria - chemistry; Bacteria - enzymology; Bacteria - isolation & purification; Bacterial cellulose; Cattle; Cellulose - chemistry; Colorimetry - methods; Copper - chemistry; Enzyme; Enzymes, Immobilized - chemistry; Flow analysis; Metal-organic framework; Metal-Organic Frameworks - chemistry; Milk - chemistry; Spectrophotometry; Urea - analysis; Urea - chemistry; Urease - chemistry; Bacterial cellulose; Adulterant; Metal-organic framework; Spectrophotometry; Enzyme; Flow analysis
• ISSN: 0308-8146; 1873-7072; 1873-7072
• DOI: 10.1016/j.foodchem.2024.140454

This work describes determining urea in milk samples using a multicommuted approach with a urease enzyme immobilized in bacterial cellulose and solid MOF as a colorimetric reagent. The Cu(2+)-MOF was characterized by FTIR spectroscopy, XRD, and SEM. The urea quantification was based on the urea hydrolysis reaction catalyzed by urease and reacted with Cu(2+)-MOF forming [Cu(NH3)4]2+, monitored at 450 nm. Linear responses were obtained from 1.0 to 50.0 mg dL−1 urea (R = 0.9959, n = 11), detection and quantitation limits of 0.082 mg dL−1 and 0.272 mg dL−1 respectively, analytical frequency of 8 determinations per hour, 0.8 mL sample solution consumption. Potential interfering studies have shown the selectivity of the proposed method. Addition and recovery tests were performed obtaining variation from 90 to 103%. Applying the F-test and t-test, the results showed no significant difference at the 95% confidence level Comparing the proposed and the reference method. [Display omitted] •Cu(2+)-MOF was used as an enzyme-based sensor for colorimetric detection of urea in milk.•The flow system using cellulose-immobilized urease in bacterial cellulose (BC).•Detection (LD) and quantification limits (LQ) were estimated at 0.082 mg dL−1 and 0.272 mg dL−1, respectively.•The analytical system has a significant reduction in reaction time and quantity of reagents.•The proposed analysis system is simple, versatile, and robust way and is viable to determine the urea in milk.