Optical Ammonia-Sensing Probe Based on Surface-Plasmon Resonance of Silver-Nanoparticle-Decorated Superparamagnetic Dendritic Nanoparticles

Abstract

Ammonia is a serious contaminant of aquaculture water due to its continuous release into the water environment during the biological processes of aquatic animals. Ammonia accumulation in water has negative environmental impacts, including eutrophication and the death of aquatic organisms. Therefore, sensitive and accurate determination of ammonia is an urgent need, especially in pisciculture systems. Here, we report the fabrication of a novel magnetic–hyperbranched nanomaterial-based ammonia-sensing probe for the fast and sensitive determination of ammonia in water. The proposed probe is composed of poly(amidoamine) (PAMAM)-coated superparamagnetic iron oxide nanoparticles (SPIONs) decorated with silver nanoparticles. Changing the ammonia concentration is associated with a corresponding change in the surface plasmon resonance property of silver nanoparticles. The proposed nanosystem was characterized with FTIR spectroscopy, SEM imaging, energy-dispersive X-ray (EDX) analysis, TEM imaging, X-ray diffractometry (XRD), and vibrating sample magnetometry (VSM). The TEM images showed a homogenous and uniform distribution of the nanoparticles with an average nanoparticle size of 200 nm, while the surface silver nanoparticles have an average particle size of 10–50 nm. The proposed optical ammonia sensor was successfully used to determine the concentration of ammonia in water samples by measuring the change in the solution absorbance at 428 nm. The obtained results revealed high recovery values (96.3–104.7%) and very low detection (LOD = 5.69 mg/L) and quantification (LOQ = 18.96 mg/L) limits. The standard plot is linear in the concentration range of 10–50 mg/L with an r2 value of 0.9980. Sandell’s sensitivity of the most promising sensor (NP-III) among the investigated systems was found to be 0.15 µg/cm2, which indicates high sensitivity.

Formation of plasmonic core/shell nanorods through ammonia-mediated dissolution of silver(i)oxide for ammonia monitoring

“…Therefore, there is an urgent need for accurate, rapid, on-site and sensitive ammonia determination, especially in fish farming systems. 30 In this study, a colorimetric sensor was developed based on the specific dissolution of silver( i ) oxide by ammonia, which triggers the activation of silver ions and the subsequent formation of core/shell gold/silver NRs. This led to changes in the surface composition, size, and aspect ratio of the AuNRs, which were accompanied by vivid color changes in the solution from light green to red/orange.…”

“…The detection limit of ammonia in the present study is lower than the reported methods. 1,[31][32][33][34][36][37][38][39] Most reports do not provide visual detection 1,[30][31][32][33][34]36,39 or clear color differentiation. 35,38 In the present study, the color changes of the sensor in the absence and presence of different ammonia concentrations are completely different and can be easily detected by the naked eye.…”

Sensitive and Reversible Ammonia Gas Sensor Based on Single-Walled Carbon Nanotubes

“…Optical sensors are another type of sensor used for ammonia detection [18]. These sensors use the absorption or fluorescence of light to detect ammonia, making them highly selective and sensitive [19]. These sensors can also detect signals through changes in the light scattering pattern [20].…”

Sensitive and Reversible Ammonia Gas Sensor Based on Single-Walled Carbon Nanotubes

“…Optical sensors are another type of sensors used for ammonia detection [18]. These sensors use the absorption or fluorescence of light to detect ammonia, making them highly selective and sensitive [19]. These sensors can also detect signals through changes in light scattering patterns [20].…”