Simple and rapid colorimetric sensing of Ni(II) ions in tap water based on aggregation of citrate-stabilized silver nanoparticles

Abstract

The presence of nickel in our water sources presents a danger to human health and aquatic organisms alike. Therefore, there is a need to detect and monitor nickel concentration in these sources. Current detection methods use instruments that are costly, resource intensive and require skilled personnel. Alternative methods that are simple and fast are needed. This study reports for the first time the development of a simple colorimetric assay for the detection of Ni 2+ in aqueous solution using citrate-stabilized silver nanoparticles. Chemical synthesis method was employed using sodium borohydride and trisodium citrate as reducing and stabilizing agents, respectively. The characterization techniques used for obtaining spectral and morphological properties were ultraviolet-visible spectroscopy and transmission electron microscopy. The resultant silver nanoparticle solution was yellow in color and exhibited an absorbance peak at 392 nm. The full width at half maximum value was 57.8 ± 1.3 nm indicating particle monodispersity. For the morphology, the nanoparticles were spherical in shape with an average size of 10.4 ± 4.5 nm. Furthermore, the colorimetric properties of the silver nanoparticles for Ni 2+ detection was investigated. Ni 2+ was visually detected through a fast solution color change from yellow to orange. Monitoring of the absorbance showed a decrease in the original 392 nm peak and broadening of the surface plasmon absorption band. These changes are attributed to the aggregation of the nanoparticles due to Ni 2+ addition which was confirmed by the transmission electron microscopy imaging. The absorption ratio (A 510 /A 392) was plotted against varying Ni 2+ concentration and it exhibited a good linear correlation from 0.7 to 1.6 mM with an R 2 of 0.9958. The limits of detection and quantification were 0.75 and 1.52 mM, respectively. Additionally, the assay was tested against other common ions and showed excellent selectivity for Ni 2+. Finally, the assay was successfully tested to detect Ni 2+ in tap water samples with an average difference of 16% from prepared concentrations. Overall, the study showed the potential of using citrate-stabilized silver nanoparticles as a colorimetric reagent for detecting Ni 2+ in aqueous solution.

Highly sensitive Ni2+ sensors based on polyurethane‐derived, label‐free carbon dots with high adsorption capacity

“…Although some other sensors produced better LODs and/or linear ranges. Our carbon dots are much simpler to prepare via a one‐step pyrolysis than the previously reported materials, e. g. hydrazone derivative, [48] pyrimidine ligand, [49] imprinted polymers, [50] and functionalized silver nanoparticles [51–53] . It is noteworthy to point out that in our previous work the carbon dots were prepared from polyurethane, which were found to be selective to Ag + [34] .…”

“…Our carbon dots are much simpler to prepare via a one-step pyrolysis than the previously reported materials, e. g. hydrazone derivative, [48] pyrimidine ligand, [49] imprinted polymers, [50] and functionalized silver nanoparticles. [51][52][53] It is noteworthy to point out that in our previous work the carbon dots were prepared from polyurethane, which were found to be selective to Ag + . [34] The differences between our previous work and this present work are in the amount of polyurethane and reaction conditions used in the synthesis.…”

Gold and Silver Nanoparticle-Based Colorimetric Sensors: New Trends and Applications

“…Before the application of the method to real samples, interference studies were performed testing some representative cations such as Ag(I), Li(I), Ca(II), and Mg(II); the method showed excellent selectivity for Ni(II) compared to the other metal ions. Lastly, the method was applied for determining Ni(II) in synthetic solutions and tap waters, giving pretty good results [79].…”

“…method was applied for determining Ni(II) in synthetic solutions and tap waters, giving pretty good results [79]. An economical and eco-friendly method based on AgNPs for sensing Al(III) was presented.…”

Green-synthesized Silver Nanoparticles as Sensor Probes for the Naked-eye Detection of Hydrogen Peroxide

“…AgNPs have been used recently for the detection of Hg(II) and Fe(II) 4 , ammonia 5 , Ba(II) and Ni(II) 6 , endrin 7 and triethylamine 8 . Compared to the gold precursor, the precursor for AgNPs has lower cost, and AgNPs are easier to synthesize 9 .…”