Perchlorate (ClO4-) has recently emerged as a widespread environmental contaminant found in groundwater and surface water, and there is a great need for rapid detection and monitoring of this contaminant. This study presents a new technique using cystamine-modified gold nanoparticles as a substrate for surface-enhanced Raman scattering (SERS) detection of perchlorate at low concentrations. A detection limit of 5x10(-6) M (0.5 mg/L) has been achieved using this method without sample preconcentration. This result was attributed to a strong plasmon enhancement by gold metal surfaces and the electrostatic attraction of ClO4- onto positively charged, cystamine-modified gold nanoparticles at a low pH. The methodology also was found to be reproducible, quantitative, and not susceptible to significant interference from the presence of anions such as sulfate, phosphate, nitrate and chloride at concentrations <1 mM, making it potentially suitable for rapid screening and routine analysis of perchlorate in environmental samples.
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http://dx.doi.org/10.1016/j.aca.2006.01.097 | DOI Listing |
Anal Bioanal Chem
June 2012
State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
A colorimetric method for the determination of thiocyanate (SCN(-)) ion with a cystamine-modified gold nanoparticle (Au NP) probe is presented. In this method, recognition is based on electrostatic attraction and directional hydrogen bonding between thiocyanate and cystamine on the surface of an Au NP. In phosphate buffer solution (PBS, pH 5.
View Article and Find Full Text PDFAnal Chem
September 2009
Department of Chemistry, Center for Advanced Sensors & Environmental Monitoring, State University of New York-Binghamton, P.O. Box 6000, Binghamton, New York 13902, USA.
Presented herein are two detection strategies for the identification and quantification of Bacillus globigii, a spore forming nonpathogenic simulant of Bacillus anthracis. The first strategy involves a label-free, metal-enhanced electrochemical immunosensor for the quantitative detection of Bacillus globigii (atrophaeus). The immunosensor comprises of antibacillus globigii (BG) antibody self-assembled onto a gold quartz crystal electrode via cystamine bond.
View Article and Find Full Text PDFJ Nanosci Nanotechnol
September 2008
Korea Food Research Institute, San 46-1, Backhyun, Bundang-gu, Songnam, Kyonggi-do 463-746, Korea.
We investigated the sensitivity enhancement in chemical sensors by coupling Au nanoparticles that have the specific size and surface density on sensor chips as those found in label-free detection systems. The Au particles with 10, 30, 60 nm diameter were conjugated by amine groups of cystamine modified chips. The surface density of Au particles was controlled by the reaction time and the concentration of the solution containing the particles.
View Article and Find Full Text PDFAnal Chim Acta
May 2006
Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States.
Perchlorate (ClO4-) has recently emerged as a widespread environmental contaminant found in groundwater and surface water, and there is a great need for rapid detection and monitoring of this contaminant. This study presents a new technique using cystamine-modified gold nanoparticles as a substrate for surface-enhanced Raman scattering (SERS) detection of perchlorate at low concentrations. A detection limit of 5x10(-6) M (0.
View Article and Find Full Text PDFAnal Biochem
March 2007
INQUIMAE - Departamento de Química Inorgánica, Analítica y Química Física Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina.
A biotin-lipopolysaccharide (biotin-LPS) conjugate was synthesized from LPS smooth from Salmonella minnesota, yielding a conjugate with a biotin/LPS ratio equal to 1:1 and endotoxic activity of 0.08 EU ng(-1). The conjugate was used in an amperometric competitive assay to determine endotoxins with endotoxin-neutralizing protein (ENP) as the recognition element.
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