NIR-Raman spectrum and DFT calculations of okadaic acid DSP marine biotoxin microprobe

Abstract

Commercially available diarrhetic shellfish poisoning (DSP) marine toxins are limited to micrograms samples invisible to the naked eye or in small amounts of micromole concentration solutions that are not suitable for normal Raman spectroscopy. As the Raman‐derived techniques are increasingly employed in various detection schemes of harmful substances, Raman spectra of the target compounds are essential for molecular recognition, detection and sensing reasons. Using a new μ‐RIM™ stainless steel hydrophobic substrate, we recorded near‐infrared micro‐Raman spectrum of okadaic acid (OA), a DSP marine biotoxin from 75 µg recrystallized toxin after drop coating deposition. Excitation with the 785‐nm line allowed the recovery and assembling of the Raman spectrum over the 100–3200 cm−1 spectral range on several OA microparticles, while the 532‐nm line excited the fluorescence emission that hampered the Raman signal. Density functional theory calculations were conducted on the isolated species both in gas phase and in ethanol solution to accurately assess and interpret the experimentally observed Raman bands. A good correlation between the experimental and theoretical Raman bands allowed for a reliable vibrational Raman assignment. Owing to the molecular geometry with intramolecular hydrogen bonds, the CC conjugated systems together with the methyl groups exhibited dominant OA Raman bands. Unlike domoic acid, an amnesic shellfish poisoning toxin whose carboxyl group showed the most intense Raman band, OA Raman characteristic band was not assigned to carboxyl group. Copyright © 2016 John Wiley & Sons, Ltd.

Surface-Enhanced Raman Scattering Detection of Fipronil Pesticide Adsorbed on Silver Nanoparticles

“…Recently, the scientist’s community has paid much attention to the spectroscopic detection of hazardous pesticide [11,12,13]. Raman methods have the advantage of easy detection in aqueous solutions with tremendous electromagnetic field enhancements on metal surfaces to provide extremely high sensitivity to monitor organic contaminants [14,15].…”

Recent advances in linear and non‐linear Raman spectroscopy. Part XI

“…They used a new μ‐RIM® stainless steel hydrophobic substrate to record near‐IR micro‐Raman spectra of okadaic acid (OA), a DSP marine biotoxin from 75 μg recrystallized toxin after drop coating deposition. Excitation with the 785‐nm line allowed the recovery and assembling of the Raman spectrum over the 100–3,200 cm −1 spectral range on several OA microparticles, while the 532‐nm line excited the fluorescence emission that hampered the Raman signal . DiGuiseppi and Schweitzer‐Stenner investigated the conformational propensities of histidine in different protonation states of the unblocked glycyl‐histidyl‐glycine peptide by vibrational and NMR spectroscopy.…”

“…Excitation with the 785-nm line allowed the recovery and assembling of the Raman spectrum over the 100-3,200 cm −1 spectral range on several OA microparticles, while the 532-nm line excited the fluorescence emission that hampered the Raman signal. [54] DiGuiseppi and Schweitzer-Stenner investigated the conformational propensities of histidine in different protonation states of the unblocked glycyl-histidyl-glycine peptide by vibrational and NMR spectroscopy. They utilized polarized Raman, FTIR, vibrational CD, and 1 H NMR spectroscopy to probe the conformational distribution of the central histidine in the unblocked tripeptide H-Gly-His-Gly-OH in D 2 O.…”

Raman spectroscopy and density functional theory study of energetically closely separated C2′‐endo and C3′‐endo pentose forms in purine nucleoside analogue drug‐gold conjugates

“…Raman spectroscopy has been applied to molecular imaging and analytics for biomedical imaging . Recently, surface‐enhanced Raman scattering (SERS) has been introduced to study the interfacial interactions between biologically important species and nanostructured materials . Over the past several decades, the chemical synthesis has led to the discovery and development of cancer therapeutic agents based on the understanding of drug uptake, molecular interaction, and cellular process .…”

“…[1] Recently, surface-enhanced Raman scattering (SERS) has been introduced to study the interfacial interactions between biologically important species and nanostructured materials. [2][3][4][5][6] Over the past several decades, the chemical synthesis has led to the discovery and development of cancer therapeutic agents based on the understanding of drug uptake, molecular interaction, and cellular process. [7] Much attention has been paid to the application of nanoparticulate intracellular delivery of anticancer drugs to cure cancers.…”