An evaluation of monovalent, divalent, and trivalent cations as aggregating agents for surface enhanced Raman spectroscopy (SERS) analysis of synthetic cannabinoids

The Analyst ◽  
2019 ◽  
Vol 144 (21) ◽  
pp. 6404-6414
Author(s):  
Thaddeus Mostowtt ◽  
Jonathan Munoz ◽  
Bruce McCord
Keyword(s):  
Raman Spectroscopy ◽  
Synthetic Cannabinoids ◽  
Detection Limits ◽  
Surface Enhanced Raman Spectroscopy ◽  
Critical Coagulation Concentration ◽  
Surface Enhanced ◽  
Nitrate Salts ◽  
Surface Enhanced Raman ◽  
Trivalent Cations ◽  
Chloride Sulfate

Monovalent, divalent and trivalent chloride, sulfate and nitrate salts were examined to determine the critical coagulation concentration (CCC) for each salt and its corresponding effect on detection limits for SERS analysis of synthetic cannabinoids.

scholarly journals The multivariate detection limit for Mycoplasma pneumoniae as determined by nanorod array-surface enhanced Raman spectroscopy and comparison with limit of detection by qPCR

The Analyst ◽  
2014 ◽  
Vol 139 (24) ◽  
pp. 6426-6434 ◽  
Author(s):  
Kelley C. Henderson ◽  
Edward S. Sheppard ◽  
Omar E. Rivera-Betancourt ◽  
Joo-Young Choi ◽  
Richard A. Dluhy ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Detection Limit ◽  
Mycoplasma Pneumoniae ◽  
Limit Of Detection ◽  
Bacterial Pathogen ◽  
Detection Limits ◽  
Nanorod Array ◽  
Surface Enhanced Raman Spectroscopy ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

The detection limits by NA-SERS and qPCR for the bacterial pathogenMycoplasma pneumoniaewere compared.

Detection of Nitrate and Sulfate Anions by Normal Raman Spectroscopy and SERS of Cationic-Coated, Silver Substrates

2000 ◽  
Vol 54 (8) ◽  
pp. 1126-1135 ◽  
Author(s):  
P. A. Mosier-Boss ◽  
S. H. Lieberman
Keyword(s):  
Raman Spectroscopy ◽  
Near Infrared ◽  
Detection Limits ◽  
Surface Enhanced Raman Spectroscopy ◽  
Sulfate Ions ◽  
Sers Substrates ◽  
Surface Enhanced ◽  
Aqueous Environments ◽  
Surface Enhanced Raman ◽  
Infrared Excitation

The use of normal Raman spectroscopy and surface-enhanced Raman spectroscopy (SERS) of cationic-coated, silver substrates to detect nitrate and sulfate ions in aqueous environments is examined. For normal Raman spectroscopy using near-infrared excitation, a linear concentration response was observed with detection limits of 260 and 440 ppm for nitrate and sulfate, respectively. Detection limits in the low parts-per-million concentration range for these anions are achieved by using cationic-coated, silver SERS substrates. Adsorption of the anions on the cationic-coated SERS substrates is described by a Frumkin isotherm.

scholarly journals Discrimination of Bacteria and Bacteriophages by Raman Spectroscopy and Surface-Enhanced Raman Spectroscopy

2007 ◽  
Vol 61 (7) ◽  
pp. 679-685 ◽  
Author(s):  
Lindsay J. Goeller ◽  
Mark R. Riley
Keyword(s):  
Raman Spectroscopy ◽  
Pathogen Detection ◽  
Detection Limits ◽  
Direct Methods ◽  
Surface Enhanced Raman Spectroscopy ◽  
E Coli ◽  
Spectral Signal ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Sampling Volume

Detection of pathogenic organisms in the environment presents several challenges due to the high cost and long times typically required for identification and quantification. Polymerase chain reaction (PCR) based methods are often hindered by the presence of polymerase inhibiting compounds and so direct methods of quantification that do not require enrichment or amplification are being sought. This work presents an analysis of pathogen detection using Raman spectroscopy to identify and quantify microorganisms without drying. Confocal Raman measurements of the bacterium Escherichia coli and of two bacteriophages, MS2 and PRD1, were analyzed for characteristic peaks and to estimate detection limits using traditional Raman and surface-enhanced Raman spectroscopy (SERS). MS2, PRD1, and E. coli produced differentiable Raman spectra with approximate detection limits for PRD1 and E. coli of 109 pfu/mL and 106 cells/mL, respectively. These high detection concentration limits are partly due to the small sampling volume of the confocal system but translate to quantification of as little as 100 bacteriophages to generate a reliable spectral signal. SERS increased signal intensity 103 fold and presented peaks that were visible using 2-second acquisitions; however, peak locations and intensities were variable, as typical with SERS. These results demonstrate that Raman spectroscopy and SERS have potential as a pathogen monitoring platform.

Characterization and Detection of Neonicotinoid Pesticides using Surface Enhanced Raman Spectroscopy and Nano-electrochemistry

2018 ◽  
Author(s):  
Niamh Creedon ◽  
Pierre Lovera ◽  
Jose Julio Gutierrez Moreno ◽  
Michael Nolan ◽  
Alan O'Riordan
Keyword(s):  
Raman Spectroscopy ◽  
Density Functional ◽  
Electrochemical Techniques ◽  
Detection Limits ◽  
Surface Enhanced Raman Spectroscopy ◽  
Quantitative Detection ◽  
Molecular Spectra ◽  
Electrochemical Approach ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

Orthogonal sensing of nitroguanidine neonicotinoid insecticides is explored by combining both surface enhanced Raman Spectroscopy (SERS) and nanoelectrochemical analysis. Silver nanostructured surfaces were fabricated for qualitative SERS-based detection of clothianidin and imidacloprid, to provide characteristic molecular spectra of the molecules, Density functional theory (DFT) studies were undertaken to assign the Raman active vibrational modes for clothianidin and imidacloprid. The Raman spectrum of clothianidin is assigned for the first time. Discrete arrays of on-chip fully integrated gold nanowire electrodes were developed to provide quantitative detection of the insecticides. Square-wave voltammetry permits highly sensitive and rapid determination of the neonicotinoids. Two electrochemical reduction peaks for clothianidin and imidacloprid were identified, and detection limits of 0.22 ng/mL and 2.15 ng/mL were subsequently achieved, respectively. These detection limits are significantly lower than previously reported electrochemical techniques and are comparable with significantly more complex and expensive chromatographic methods. By employing both techniques in combination, SERS characterisation provides the unique molecular fingerprint of each pesticide, while the nanoelectrochemical measurement provides a quantitative determination to ultra-low limits of detection. This combined spectro-electrochemical approach has the potential to significantly reduce false positives, that arise in remote monitoring, greatly increasing the robustness and credibility of these measurements.

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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