This work introduces a wireless, solid-state, portable, and automated device capable of semi-continuously 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 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 five seconds 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.