A SERS-BASED ANALYZER FOR POINT AND CONTINUOUS WATER MONITORING OF CHEMICAL AGENTS AND THEIR HYDROLYSIS PRODUCTS

2007 ◽  
Vol 17 (04) ◽  
pp. 719-728 ◽  
Author(s):  
STUART FARQUHARSON ◽  
FRANK E. INSCORE
Keyword(s):  
Sulfur Mustard ◽  
Active Material ◽  
Hydrolysis Product ◽  
Chemical Warfare Agents ◽  
Surface Enhanced Raman Spectroscopy ◽  
Water Monitoring ◽  
Hydrolysis Products ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Warfare Agents

Protection of military personnel and civilians from water supplies poisoned by chemical warfare agents (CWAs) requires an analyzer that has sufficient sensitivity (μg/L, ppb), specificity (differentiate the CWA from its hydrolysis products), and speed (less than 10 minutes) to be of value. In an effort to meet these requirements, we have been investigating the ability of surface-enhanced Raman spectroscopy (SERS) to detect cyanide and sulfur mustard in water. In our work, we have developed a novel SERS-active material that consists of a porous glass with trapped metal particles. Previously, we coated the inside walls of glass vials and measured cyanide at 1 mg/L in water in as little as 1 minute. However, measurements of sulfur mustard have only been measured to 10 mg/L. Recently, we filled glass capillaries with the SERS-active material. Here we describe measurements of cyanide, sulfur mustard, and it's hydrolysis product, thiodiglycol, using these capillaries and a portable Raman analyzer suitable for point and continuous water monitoring.

Surface-Enhanced Raman Spectra of VX and its Hydrolysis Products

2005 ◽  
Vol 59 (5) ◽  
pp. 654-660 ◽  
Author(s):  
Stuart Farquharson ◽  
Alan Gift ◽  
Paul Maksymiuk ◽  
Frank Inscore
Keyword(s):  
Raman Spectroscopy ◽  
Vibrational Mode ◽  
Sol Gel ◽  
Surface Enhanced Raman Spectroscopy ◽  
Nerve Agent ◽  
Methylphosphonic Acid ◽  
Hydrolysis Products ◽  
Chemical Agents ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

Detection of chemical agents as poisons in water supplies not only requires μg/L sensitivity, but also requires the ability to distinguish their hydrolysis products. We have been investigating the ability of surface-enhanced Raman spectroscopy (SERS) to detect chemical agents at these concentrations. Here we expand these studies and present the SERS spectra of the nerve agent VX (ethyl S-2-diisopropylamino ethyl methylphosphonothioate) and its hydrolysis products, ethyl S-2-diisopropylamino methylphosphonothioate, 2-(diisopropylamino) ethanethiol, ethyl methylphosphonic acid, and methylphosphonic acid. Vibrational mode assignments for the observed SERS peaks are also provided. Overall, each of these chemicals produces a series of peaks between 450 and 900 cm−1 that are sufficiently unique to allow identification. SERS measurements were performed in silver-doped sol-gel-filled capillaries that are being developed as part of an extractive point sensor.

Interfacial self-assembly of nanostructured silver octahedra for surface-enhanced Raman spectroscopy

2018 ◽  
Vol 11 (05) ◽  
pp. 1850028 ◽  
Author(s):  
Anna A. Semenova ◽  
Alexander E. Baranchikov ◽  
Vladimir K. Ivanov ◽  
Eugene A. Goodilin
Keyword(s):  
Raman Spectroscopy ◽  
Self Assembly ◽  
Hot Spots ◽  
Active Material ◽  
Surface Enhanced Raman Spectroscopy ◽  
Interfacial Region ◽  
Pickering Emulsions ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Scattering Signal

A novel robust and effective approach is suggested to form thin film substrates for surface-enhanced Raman spectroscopy (SERS) using interfacial self-assembly in demixing water/toluene Pickering emulsions collecting silver octahedral mesocages onto a finally flat interfacial region. The freely floating self-assembled silver films obtained after toluene evaporation can be transferred onto various substrates including those with an ordered superficial relief causing a further alignment of silver octahedra. A special porous aggregative structure of the octahedra mesocages provokes a great number of hot spots allowing a large amplification of Raman scattering signal of model dye analytes and molecular thiol products of crude oil desulfurization. The suggested method seems to be an easy scaling route for SERS active material production.

scholarly journals Detection of nerve gases using surface-enhanced Raman scattering substrates with high droplet adhesion

Nanoscale ◽  
2016 ◽  
Vol 8 (3) ◽  
pp. 1305-1308 ◽  
Author(s):  
Aron Hakonen ◽  
Tomas Rindzevicius ◽  
Michael Stenbæk Schmidt ◽  
Per Ola Andersson ◽  
Lars Juhlin ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Chemical Warfare Agents ◽  
Surface Enhanced Raman Scattering ◽  
Chemical Warfare ◽  
Security Issue ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Warfare Agents ◽  
Enhanced Raman Scattering ◽  
Global Concern

Threats from chemical warfare agents, commonly known as nerve gases, constitute a serious security issue of increasing global concern because of surging terrorist activity worldwide.

Bacterial detection and differentiation via direct volatile organic compound sensing with surface enhanced Raman spectroscopy

2017 ◽  
Author(s):  
Caitlin S. DeJong ◽  
David I. Wang ◽  
Aleksandr Polyakov ◽  
Anita Rogacs ◽  
Steven J. Simske ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Bacterial Infections ◽  
Direct Detection ◽  
Point Of Care ◽  
Surface Enhanced Raman Spectroscopy ◽  
E Coli ◽  
Recent Emergence ◽  
Surface Enhanced ◽  
Volatile Organic ◽  
Surface Enhanced Raman

Through the direct detection of bacterial volatile organic compounds (VOCs), via surface enhanced Raman spectroscopy (SERS), we report here a reconfigurable assay for the identification and monitoring of bacteria. We demonstrate differentiation between highly clinically relevant organisms: <i>Escherichia coli</i>, <i>Enterobacter cloacae</i>, and <i>Serratia marcescens</i>. This is the first differentiation of bacteria via SERS of bacterial VOC signatures. The assay also detected as few as 10 CFU/ml of <i>E. coli</i> in under 12 hrs, and detected <i>E. coli</i> from whole human blood and human urine in 16 hrs at clinically relevant concentrations of 10<sup>3</sup> CFU/ml and 10<sup>4</sup> CFU/ml, respectively. In addition, the recent emergence of portable Raman spectrometers uniquely allows SERS to bring VOC detection to point-of-care settings for diagnosing bacterial infections.

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