Raman Spectroscopic Studies of Methane Gas Hydrates

Abstract

A brief review of the Raman spectroscopic studies of methane gas hydrates is given, supported by some new measurements done in our laboratory.     

Recent Analytical Applications of Molecular Spectroscopy in Bioorganometallic Chemistry—Part I: Metal Carbonyls

Abstract: This is the first part of a two-part review on the analytical applications of molecular spectroscopy in bioorganometallic chemistry since 2005. In this case, radiopharmaceutical studies are included and the review is focused particularly on biological molecules labeled with metal carbonyl fragments.     

A Review of the State of the Art,Limitations, and Perspectives of Infrared Spectroscopy for the Analysis of Wine Grapes,Must, and Grapevine Tissue

Abstract

As a fast and easy-to-operate technique, infrared (IR) spectroscopy has gained wide industrial acceptance for routine wine analysis. Considering the continuing improvements in hardware and software design and the analytical requirements of real-time or multiparametric analysis by the modern grape and wine industry, it is anticipated that in the near future IR spectroscopy will progressively become a routine method for process monitoring and process control in different stages of grape and wine production. This review highlights recent developments and applications of IR spectroscopy (near- and mid-infrared) to measure compositional parameters in wine grapes, grape juice, and grapevine tissues (e.g., leaves, stems, grapevine wood). In addition, some critical aspects and limitations in instrument availability, type of application, and overall understanding of the technology, which can be barriers for adoption of IR technologies by the grape and wine industry, will be discussed.     

Infrared Difference Spectroscopy as a Physical Tool to Study Biomolecules

Abstract

This brief review focuses on the information that can be obtained for biomolecules, especially proteins, by using the technique infrared-induced difference spectroscopy.     

A REVIEW OF RECENT APPLICATIONS OF NEAR INFRARED SPECTROSCOPY,AND OF THE CHARACTERISTICS OF A NOVEL PbS CCD ARRAY-BASED NEAR-INFRARED SPECTROMETER

ABSTRACT

Near-infrared spectroscopy (NIRS) has been gaining popularity as an analytical tool due to advances in the power of personal computers, which allow the extraction of chemical and physical information about a sample, and the utilization of cost efficient and robust CCD array-based spectrometers. In this review, applications of NIRS are explored, within various fields of analytical chemistry, which take advantage of the inherent rapid analysis time and minimal sample preparation that is possible. For the purposes of illustration, the usefulness and limitations of a novel, PbS array-based spectrometer are described in the context of its application to the analysis of a variety of samples.     

A Wavenumber,Intensity, and Resolution Standard for High Resolution Ultraviolet/Visible Fourier Transform Spectroscopy

Abstract

The Re I (527. 55 nm, 18955 cm^?1) emission line from a hollow cathode lamp (HCL) is proposed as a standard for wavenumber accuracy and precision, resolution accuracy and precision and intensity precision. The Los Alamos Fourier transform spectrometer measured the HCL emission at high resolution (0. 026 cm^?1). The advantages of this spectral line to other emission standards is discussed.     

Synthesis, Crystal, Absorption and Fluorescence Spectroscopy of Nitro-Stilbene Derivatives with Benzophenones

In this paper, we have presented a range of new nitro-stilbene derivatives with benzophenones via ether or ester bridged bond. These nitro-stilbene derivatives with benzophenones have been conveniently obtained by condensation reaction. The linked benzophenones were efficiently introduced to nitro-stilbene dyes. The structures of these compounds have been characterized with NMR and element analysis. The single crystals of two target compounds (11 and 12) have been obtained, and their X-ray crystallographic data have been determined and discussed. Remarkably different absorption and fluorescence spectroscopy was observed for nitro-stilbene derivatives with benzophenones via different linked bonds. The results show that electron-donating or electron withdrawing bridged bonds have significant influence on the absorption and fluorescence spectroscopy, which makes it possible for the development of ideal nitro-stilbene dyes with benzophenones through chemical strategy.     

Synthesis and Antitumor,Antioxidant Effects Studies of N-Ethylpiperazine Substitute Thiourea Ligands and Their Copper(II) Complexes

A series of N-ethylpiperazine substitute thioureas [C₆N₂H₁₃NHCSNHR], where R = -C₃H₅ (L ₁ ), -C₁₀H₇ (L ₂ ), and -C₇H₇ (L ₃ ), and their copper (II) complexes have been synthesized. These ligands and complexes have been characterized by elemental analyses, IR, ¹H and ¹³C-NMR spectra, UV-Vis, magnetic susceptibility, thermogravimetrical analyses, and MALDI-TOF MS. In vitro antitumor activity of ligands and their complexes has been screened toward several tumor cell lines. The effects on these complexes of the growth of L1210 and MCF7 were studied comparatively with that of free ligands. Antioxidant and radical scavenging activities of synthesized compounds were determined by various in vitro assays including 1,1-diphenyl-2-picryl-hydrazyl free radicals (DPPH), 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid radicals (ABTS+), and ferrous ion (Fe²⁺) chelating activities. Moreover, these activities were compared to synthetic and standard antioxidant trolox. The results showed that the synthesized compounds had effective antioxidant power.     

Internal Reflection and ATR Spectroscopy

Abstract

The connection between ATR spectroscopy and the physical phenomena of internal reflection and evanescent wave is reviewed. In this context advanced aspects of ATR spectroscopy are discussed. A brief review of the accessories used for ATR measurements is given along with a cursory review of general strategies for their incorporation into FTIR spectrometers.     

Raman Spectroscopy for Protein Analysis

Abstract

Proteins are essential parts of organisms and participate in virtually every process within cells. Raman spectroscopy can be a powerful tool for the characterization of modified amino acids and proteins. In addition to the potential for quantitative results, it offers the advantage of not requiring any sample preparation. This review focuses on applications for protein analysis, published in the period 2010–2014.     

Process Analytical Chemistry: Applications of Ultraviolet/Visible Spectrometry in Environmental Analysis: An Overview

Abstract

Process analyzers based on the selective absorption of the ultraviolet (UV) and/or visible (VIS) radiation provide an on-line monitoring highly reliable of the composition and the industrial process control.

This review provides information about the technological advances in this area and its industrial applications, especially environmental applications.     

Investigation of the Kinetics of Curing Reaction for the Resin Matrix Polymer Composite Based on Near-Infrared Spectroscopy

Abstract

Near-infrared (NIR) spectroscopy is a rapid and nondestructive method for the simultaneous measurement of different constituents in resin matrix polymer composites. This strategy has been applied in the synthesis of resin matrix polymer composites. In this article, we mainly review the control of curing reaction kinetics of the phenolic, epoxy resin, polyester resin, polyurethane, and other polymer resin based on NIR spectra, which is important to control the quality of the resin matrix polymer composites during synthesis.     

Application of Spectroscopy and Microscopy Techniques in Surface Coatings Evaluation: A Review

Abstract: This article presents a review of the published articles related to the novel application of spectroscopy and microscopy methods in paint and coatings quality evaluation. Traditional and simple techniques have been used in paint and coating industry for many years and proven to be effective. However, the paint and coating industry faces new formulations with nontraditional applications. Therefore, the industry needs to adjust itself with the current sophisticated production and testing methods. There are a number of modern microscopy and spectroscopy techniques that can be utilized in the paint and coating industry for a better understanding of the product quality and/or application performance. This, in particular, is highly applicable in modern and nontraditional applications such as nanotechnology and smart coatings. Though importance of spectroscopy and microscopy methods is being increasingly recognized in the industry, there is no current comprehensive review available to highlight the need for novel application of these techniques in surface coatings evaluations.     

Determination of Total Petroleum Hydrocarbon (TPH) and Polycyclic Aromatic Hydrocarbon (PAH) in Soils: A Review of Spectroscopic and Nonspectroscopic Techniques

Abstract: In the analysis of petroleum hydrocarbon–contaminated soils for total petroleum hydrocarbons (TPHs) and polycyclic aromatic hydrocarbons (PAHs), the roles of spectroscopic and nonspectroscopic techniques are inseparable. Therefore, spectroscopic techniques cannot be discussed in isolation. In this report, spectroscopic techniques including Raman, fluorescence, infrared, and visible and near-infrared (Vis-NIR) spectroscopies, as well as mass spectroscopy (coupled to a gas chromatograph) and nonspectroscopic techniques such as gravimetry, immunoassay, and gas chromatography with flame ionization detection are reviewed. To bridge the perceived gap in coverage of the quantitative applications of Vis-NIR spectroscopy in the rapid determination of TPHs and PAHs in soils, a detailed review of studies from the period 1999–2012 are presented. This report also highlights the strengths and limitations of these techniques and evaluates their performance from the perspective of their attributes of general applicability, namely economic portability, operational time, accuracy, and occupational health and safety considerations. Overall, the fluorescence spectroscopic technique had the best performance (85% total score) in comparison to the others, and the gravimetric technique performed the least (60% total score). Method-specific solutions geared toward performance improvement are also suggested.     

Spectroscopic interrogation and charge transport properties of molecular transistors

ABSTRACT

Molecular transistors have been extensively investigated as the building blocks for the ultimate miniaturization of electronic devices. They are assembled from single molecules and molecular monolayers serving as a current-carrying channel in a conventional field-effect transistor configuration, in which gate electrodes have been electrically or electrochemically implemented in several types of test beds such as electromigration junctions, mechanically controllable break junctions, and devices with carbon-based electrodes. The energy level alignments of the component molecules incorporated into the transistor can be tuned using molecular orbital gating and it can ultimately control the flow of charge carriers. Herein, we review recent progress in studying spectroscopic characterization techniques and charge transport properties of molecular transistors.     

Double-stranded helical lanthanide(III) supramolecular networks with rigid diimine ligands: Synthesis, structure, and physical properties

Two lanthanide coordination complexes [Nd(NO₃)₃(CH₃OH)₂(4,4′-bipy)₂] (1) (4,4′-bipy=4,4′-bipyridine) and [4,4′-Hbipy][La(NO₃)₄(H₂O)₂(4,4′-bipy)] (2), with a salt of cationic diprotonated 4,4′-bipy, [2(4,4′-H₂bipy)][4(NO₃)] (3), have been identified and isolated from a methanol solution of Ln(NO₃)₃·6H₂O, 4,4′-bipyridine and pyrazine in 1:2:1 ratio. Their structures have been determined by single-crystal X-ray diffraction analyses, which reveal that 1 has an interesting three-dimensional supramolecular architecture containing 2₁ double-stranded helical chains through hydrogen bonding and π–π interactions, while 2 and 3 have well defined infinite chiral 3D open networks that undergo self-interpenetration. The electrospray ionization mass spectra (ESI-MS) indicate that the covalent complex has higher stability than the electrostatic bonding one. ESI-MS/MS of these ions reveal that the Ln–O bond forms a stronger coordinated bonding than that of Ln–N system and the nitrate anion remains bound to the lanthanide centers after complete dissociation in methanol solution.     

Applications of Terahertz Spectroscopy in the Field of Construction and Building Materials

Abstract: In last two decades, rapid development in the field of terahertz (THz) technology has opened new possibilities for creating innovative imaging and sensing systems. Although the applications of THz technology in different sectors constantly increase, the construction industry lags behind them. The aim of this article is to review the current applications of THz spectroscopy in research and industry related to construction and building materials, along with the key drawbacks of technology and recommendations for future use. The review concludes that THz spectroscopy and imaging have promising potential and provide many opportunities for applications in construction and building materials characterization.     

Vibrational Spectroscopy in Clinical Analysis

Abstract: Vibrational spectroscopy includes several different techniques, the most important of which are mid-infrared (IR), near-IR, and Raman spectroscopy. Raman and mid-IR spectroscopy are complementary techniques and usually both are required to completely measure the vibrational modes of a molecule. Vibrational spectrometry covers a series of well-established analytical methodologies suitable to be employed for both qualitative and quantitative purposes. In the first part of this review, we will focus on theoretical aspects related to vibrational techniques; in the second part, the most important papers, published during the period 2005–2014, related to clinical analysis performed with vibrational spectroscopy techniques will be critically discussed.     

Application of Vibrational Spectroscopy in Combination with Chemometrics Techniques for Authentication of Herbal Medicine

Abstract: One of the emerging issues in herbal medicine is its authenticity. The substitution of highly valuable materials in herbal medicine with lower ones is common practice in the herbal medicine industry. This practice can cause serious effects or be harmful to human health; therefore, the authentication of herbal medicine using analytical techniques is necessary. Due to its capability as fingerprint technique, vibrational spectroscopy (infrared and Raman), especially in combination with several chemometrics techniques, is the method of choice for authentication purposes. This review highlights the use of mid-infrared, near-infrared, and Raman spectroscopy for authentication of herbal medicine, either in raw materials or in final products.     

Structural,morphological, composition and optical properties of undoped zinc oxide thin films prepared by spray pyrolysis method: effect of solution concentrations

Abstract

The aim of this paper is the study of transparent undoped zinc oxide thin films obtained by spray pyrolysis technique on glass substrates heated at 350?°C from 0.1 to 0.4?mol solution concentrations using zinc acetate dehydrate as precursor. The X-ray diffraction patterns and Raman spectrometry with respect to Urbach energy and wurtzite structure, show that the maximum value of the high frequency intensity E₂ and the optimal value of the optical gap are obtained at 0.2?mol concentration. Furthermore, an appropriate transparency is obtained and that makes these films suitable for photovoltaic windows layer cells.