Abstract
The development of reliable and highly sensitive methods for heavy metal detection is a critical task for protecting the environment and human health. In this study, a qualitative colorimetric sensor that used mercaptosuccinic-acid-functionalized gold nanoparticles (MSA-AuNPs) to detect trace amounts of Fe(III) ions was developed. MSA-AuNPs were prepared using a one-step reaction, where mercaptosuccinic acid (MSA) was used for both stabilization, which was provided by the presence of two carboxyl groups, and functionalization of the gold nanoparticle (AuNP) surface. The chelating properties of MSA in the presence of Fe(III) ions and the concentration-dependent aggregation of AuNPs showed the effectiveness of MSA-AuNPs as a sensing probe with the use of an absorbance ratio of A530/A650 as an analytical signal in the developed qualitative assay. Furthermore, the obvious Fe(III)-dependent change in the color of the MSA-AuNP solution from red to gray-blue made it possible to visually assess the metal content in a concentration above the detection limit with an assay time of less than 1 min. The detection limit that was achieved (23 ng/mL) using the proposed colorimetric sensor is more than 10 times lower than the maximum allowable concentration for drinking water defined by the World Health Organization (WHO). The MSA-AuNPs were successfully applied for Fe(III) determination in tap, spring, and drinking water, with a recovery range from 89.6 to 126%. Thus, the practicality of the MSA-AuNP-based sensor and its potential for detecting Fe(III) in real water samples were confirmed by the rapidity of testing and its high sensitivity and selectivity in the presence of competing metal ions.
Highlights
Nowadays, control of the quality and composition of consumed drinking water is in extremely demand
The preferred coordination of mercaptosuccinic acid (MSA) and Fe(III) toward forming a stable chelate complex was demonstrated experimentally in an electrochemical system using a gold electrode modified with MSA [47]
The aggregation of MSA-AuNPs in the presence of Fe(III) ions caused the delocalization of conduction electrons of the AuNPs through the neighboring particles, which led to a shift in the surface plasmon resonance toward lower energies
Summary
Control of the quality and composition of consumed drinking water is in extremely demand. The main form of iron that is present in surface waters is a complex compound of Fe(III) with dissolved organic and inorganic compounds [2]; these ions are the object of study. The process of transformation of Fe(III) to Fe(II) may take place [3], but the inorganic. Fe(II) oxidizes back to Fe(III) in a few minutes [4]. This process depends on the redox potential of natural water. Since a high consumption of Fe(III) can cause toxic effects [5], the determination of Fe(III) content in drinking water resources is of great importance for human life
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
