Colorimetric Optode Sensor with Tripodal Ionophore for Rapid Urinary Ammonium Determination

Area of Science:

• Analytical Chemistry
• Chemical Sensing
• Biomedical Diagnostics

Background:

• Urinary ammonium is a key indicator for renal metabolic acidosis.
• Accurate, high-throughput measurement of urinary ammonium is needed.
• Existing sensors have limitations in speed and throughput.

Purpose of the Study:

• To develop a novel ammonia chemical sensor for rapid and accurate urinary ammonium determination.
• To enhance sensor selectivity for free ammonia (NH3).
• To adapt the sensor for high-throughput point-of-care testing.

Main Methods:

• Development of an ion-selective optode sensor.
• Utilized specific ionophores and a PTFE gas-permeable film for NH3 selectivity.
• Employed a low basicity chromoionophore indicator and a tripodal ammonium receptor.
• Adapted the optode into a multiwell format.

Main Results:

• Achieved a markedly reduced response time (detection within seconds).
• Obtained a limit of detection (LOD) of approximately 15 nM in colorimetric mode.
• Successfully determined total inorganic ammonia in undiluted human urine.
• Demonstrated potential for high-throughput testing via multiwell adaptation.

Conclusions:

• The developed ammonia sensor offers rapid, selective, and sensitive detection of urinary ammonium.
• The sensor's design overcomes limitations of previous methods, enabling quicker analysis.
• The multiwell format facilitates high-throughput point-of-care testing for clinical diagnostics.