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Updated: Feb 6, 2026

Fast and Accurate Exhaled Breath Ammonia Measurement
Published on: June 11, 2014
A Handheld, Colorimetric Optoelectronic Dynamics Analyzer for Measuring Total Ammonia of Biological Samples
Nai-Yuan Liu1,2, Pinar Cay-Durgun1, Tianmiao Lai1,2
1School for Engineering of Matter, Transport, and EnergyArizona State UniversityTempeAZ85287USA.
Abstract:
This paper introduces a wireless, solid-state, portable, and automated device capable of measuring the total ammonia [ammonia (NH3) and ammonium (NH4+)] levels of fluids, including biological samples. This device reliably measures the total ammonia of biological samples (e.g., urine) faster than the current ammonia quantification techniques. Medical professionals typically estimate NH4+ levels using error-prone indirect measurement techniques (i.e., urine anion gap), which are time-consuming and are seldom suitable for periodic measurements. Several instantaneous measurements of total ammonia levels in a patient urine could be utilized as an early warning for both acid-base and/or potassium disturbances. Given the device's operation mechanism, it is able to quantify the total ammonia concentration within a biological sample in only 5 s and can simultaneously transmit data to other devices via Bluetooth. The analytical operation demonstrated high sensitivity, high specificity, fast reversibility, rapid response time, and has enabled the accurate determination of total ammonia concentration in urine samples produced by subjects who had consumed diets of variable protein compositions.
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