Flow injection analysis biosensor for urea analysis in adulterated milk using enzyme thermistor.

Area of Science:

• Analytical Chemistry
• Biotechnology
• Food Safety

Background:

• Urea adulteration in milk poses significant health risks, particularly to vulnerable populations.
• Existing diagnostic tools for urea detection in milk lack sophistication and reliability.
• A need exists for advanced, accurate, and efficient methods to monitor urea levels in milk.

Purpose of the Study:

• To develop and validate a flow injection analysis-enzyme thermistor (FIA-ET) biosensing system for detecting urea in adulterated milk.
• To assess the performance characteristics of the developed biosensor, including its linear range, precision, and stability.
• To compare the efficacy of the FIA-ET biosensor with conventional methods for urea analysis in milk.

Main Methods:

• Immobilization of urease enzyme (from Jack bean) onto controlled pore glass (CPG) and packing into a thermistor column.
• Utilizing the specific heat generated from urea hydrolysis for detection via the enzyme thermistor.
• Employing a filtration strategy and matrix matching for analyzing urea in complex milk matrices.
• Evaluating sensor response time, linear range (1-200 mM), recovery rates (97.56-108.7%), and operational stability (up to 180 days).

Main Results:

• The FIA-ET biosensor demonstrated a linear detection range of 1-200 mM for urea.
• High precision was observed with % R.S.D. of 0.96 in buffer and 0.95 in spiked milk samples.
• The biosensor exhibited a rapid response time of 2 minutes and excellent operational stability.
• The developed system showed good agreement with the established colorimetric method for urea quantification.

Conclusions:

• The FIA-ET biosensing system provides a sophisticated, reliable, and effective method for detecting urea in adulterated milk.
• This technology offers a promising solution for monitoring urea levels, ensuring milk safety and protecting public health.
• The biosensor's stability and accuracy make it suitable for both low and high-level urea detection in diverse milk samples.