Flow field-flow fractionation (Fl-FFF) with off-line electrothermal atomic absorption spectrometry (ETAAS) detection was developed and employed for particle size characterization of Ag NPs stabilized by citrate, pectin, and alginate. Citrate stabilized-Ag NPs were prepared from sodium borohydride reduction of silver nitrate. Sodium citrate was used as the capping agent to stabilize Ag NPs and prevent the aggregation process. Pectin stabilized- and alginate stabilized-Ag NPs were prepared from ascorbic acid reduction of silver nitrate. Pectin and alginate were used as the capping agent for pectin stabilized- and alginate stabilized-Ag NPs, respectively. Three types of Ag NPs were characterized by using FlFFF, zeta potentiometer, and TEM technique. The mean particle sizes of Ag NPs as characterized by FlFFF were 9 nm, 19 nm, and 45 nm for citrate stabilized-, pectin stabilized-, and alginate stabilized-Ag NPs, respectively, in deionized water. Further, FlFFF with ETAAS detection was employed to observe the aggregation of Ag NPs of various types in environmental water in the absence and presence of humic acid. Citrate stabilized-Ag NPs underwent aggregation more rapid than the pectin stabilized- and alginate stabilized-Ag NPs as the latter two types were sterically stabilized. Further, humic acid could prolong the stability of Ag NPs in the environment.
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http://dx.doi.org/10.1016/j.chroma.2010.12.040 | DOI Listing |
Spectrochim Acta A Mol Biomol Spectrosc
December 2024
State Key Laboratory of Systems Medicine for Cancer, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, PR China; Institute of Medical Robotics, Shanghai Jiao Tong University, Shanghai 200240, PR China; Shanghai Key Laboratory of Gynecologic Oncology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, PR China. Electronic address:
Label-free surface-enhanced Raman spectroscopy (SERS) has attracted extensive attention as an emerging technique for molecular phenotyping of biological samples. However, the selective enhancement property of SERS mediated by complicated interactions between substrates and analytes is unfavorable for molecular profiling. The electrostatic force is among the most dominating interactions that can cause selective adsorption of molecules to charged substrates.
View Article and Find Full Text PDFChemosphere
August 2024
Department of Polymer Science, University of Madras, Guindy Campus, Chennai, 600025, Tamil Nadu, India. Electronic address:
In this report, we have developed highly water soluble and stable silver nanoparticles (Ag NPs) utilizing N-Cholyl Mercapto Histidine (NCMH) as a reducing and stabilizing agent with near the primary critical micellar concentration (CMC) under ambient sunlight irradiation. Moreover, The NCMH was firstly synthesized by demonstrating the reaction between cholic acid and 2- Mercapto Histidine through a simple acid amine coupling approach. The primary and secondary CMC of NCMH surfactant was measured by pyrene (1 × 10 M) as a fluorescent probe, and values were found to be 3.
View Article and Find Full Text PDFNanomaterials (Basel)
April 2022
Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety Control, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
Monitoring food quality throughout the food supply chain is critical to ensuring global food safety and minimizing food losses. Here we find that simply by mixing an aqueous solution of sugar-stabilized Ag and amines in an open vessel leads to the generation of Ag NPs and an intelligent evaluation system based on a colorimetric Ag probe is developed for real-time visual monitoring of food freshness. The self-assembly reaction between methylamine (MA) generated during meat storage and the colorimetric Ag probe produces different color changes that indicate changes in the quality of the meat.
View Article and Find Full Text PDFJ Am Chem Soc
October 2021
The Institute of Chemistry, Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Transient, dissipative, aggregation and deaggregation of Au nanoparticles (NPs) or semiconductor quantum dots (QDs) leading to control over their transient optical properties are introduced. The systems consist of nucleic acid-modified pairs of Au NPs or pairs of CdSe/ZnS QDs, an auxiliary duplex L/T, and the nicking enzyme Nt.BbvCI as functional modules yielding transient aggregation/deaggregation of the NPs and dynamically controlling over their optical properties.
View Article and Find Full Text PDFBeilstein J Nanotechnol
August 2021
Departamento Acadêmico de Física (DAFIS-CT), Universidade Tecnológica Federal do Paraná - UTFPR - Curitiba, Brazil.
Despite all recent advances in medical treatments, infectious diseases remain dangerous. This has led to intensive scientific research on materials with antimicrobial properties. Silver nanoparticles (Ag-NPs) are a well-established solution in this area.
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