Urea enzymatic hydrolysis reaction: optimization by response surface methodology based on potentiometric measurements

Area of Science:

• Analytical Chemistry
• Biochemistry
• Chemometrics

Background:

• Urea hydrolysis by urease is a critical biochemical reaction.
• Accurate urea quantification is essential in clinical diagnostics and environmental monitoring.
• Ion-selective electrodes (ISEs) offer potential for urea measurement but face selectivity challenges.

Purpose of the Study:

• To optimize the enzymatic hydrolysis of urea using urease.
• To develop a robust analytical method for urea determination.
• To address and overcome the selectivity issues of ammonium (NH4+) ISEs in real samples.

Main Methods:

• Chemometric response surface methodology (RSM) for optimization.
• Initial rate potentiometric measurements using an NH4+ ion-selective electrode (ISE).
• Preliminary "one at a time" (OVAT) procedure to define critical variable ranges.

Main Results:

• RSM quadratic model demonstrated high appropriateness (R(2)=90.1%) for urea hydrolysis optimization.
• Analytical characteristics including linearity, detection limits, precision, and recovery were evaluated.
• The kinetic initial rate measurement method successfully mitigated interference from Na+ and K+ ions.

Conclusions:

• The optimized method provides a reliable approach for urea quantification.
• RSM is effective for optimizing enzymatic reactions involving ISE measurements.
• The developed assay is validated for urea determination in both laboratory and human serum samples.