A Capacitive Sensor, Exploiting a YSZ Functional Layer, for Ammonia Detection

Abstract

In different fields, the need for low-cost sensors allowing an early detection of (bio)quantities is emerging. This article deals with the design, realization, and characterization of a low-cost sensor for ammonia detection realized by fast prototyping techniques. The sensor is part of a more complex system aimed to assess the level of phenylalanine levels in biological fluids (blood, saliva, or urine), which would allow the development of a new approach for the self-monitoring of patients with the phenylketonuria (PKU) metabolic disorder. The obtained experimental results encourage the further development of the proposed approach. In particular, the sensor behavior has been investigated for an ammonia concentration in the range [0-2000] µM. The developed sensor prototype shows a responsivity of 3.53 × 10 −14 F/µM, a resolution of 0.15 µM, and a span-to-resolution of 1.3 × 10 4 .

Room-Temperature NH3 Gas Surface Acoustic Wave (SAW) Sensors Based on Graphene/PPy Composite Films Decorated by Au Nanoparticles with ppb Detection Ability

“…Accordingly the SAW sensor coated with AuNPs-G/PPy hybrid nanocomposite film can selectively de tect ammonia at ppm levels in dry air at room temperature despite the presence of com mon interfering gases. Table 3 shows some of the NH3 sensors operating at room temperature that are re ported in the literature [11,14,15,18,21,[33][34][35]. Compared to other ammonia sensors, th apparent frequency response in the present work is rapidly towards ppb-level NH Hence, the present EWC/SPUDT SAW sensor coated with AuNPs-G/PPy hybrid nano composite film is able to sensitively detect NH3 concentrations of the order of parts per billion at room temperature.…”

A Phenylalanine Ammonia Lyase Capacitive Sensor for Phenylalanine Detection

“…Most NH 3 sensors are aimed at gas detection [3], while few approaches address the quantification of NH 3 (aq) [4], none of which provides solutions for measurements in small volumes. The modeling and design flow of the sensor are discussed in [5], while the ability of YSZ to detect NH 3 (aq) is demonstrated in [6]. In this paper, the behavior of the complete sensor is investigated, including the Phe-PAL enzymatic reaction.…”

A highly sensitive colorimetric approach based on tris (bipyridine) Ruthenium (II/III) mediator for the enzymatic detection of phenylalanine

“…Phenylalanine ammonia lyase (PAL) was the first investigated enzyme. It converts Phe to trans -cinnamic acid, producing a quantitative amount of ammonia, which can be detected by direct optical measurements ( Sari et al, 2022 ) through an easy color change of the pH indicator ( Villalonga et al, 2008 ) or by capacitive measurements using zirconia oxide nanostructures ( Ando et al, 2022 ). The PDH is the most investigated NAD-dependent enzyme used for the development of enzymatic-analytical assays for Phe recognition.…”