Showing papers in "Applied Spectroscopy Reviews in 2011"

Applications of Raman Spectroscopy in Agricultural Products and Food Analysis: A Review

Abstract: Raman spectroscopy has been gaining popularity as an analytical tool due to advances in development of Raman spectrometry and the power of personal computers. Due to to its narrow and highly resolved bands, Raman spectroscopy allows for nondestructive extraction of chemical and physical information about samples and aids in rapid on-line analysis without any special sample preparation. In this review, Raman spectroscopic techniques such as dispersive Raman spectroscopy, Fourier transform Raman spectroscopy, surface-enhanced Raman spectroscopy, and spatially offset Raman spectroscopy are briefly introduced. In addition, applications of Raman spectroscopy are explored, within various fields of agricultural products and food, including fruits and vegetables, crops, meat and dairy products, oil, as well as beverages. In addition, some discussion on the importance of Raman spectroscopy as fundamental and applied research of agricultural products and food is provided.

Recent Developments in Ion Mobility Spectrometry

Abstract: The general principles and technical implementations of traditional time-of-flight ion mobility spectrometers and analyzers with field-dependent mobilities were reviewed in our last article in this journal. Recent advances in instrumentation and new applications since 2006 are highlighted in this review. In addition to traditional applications as military chemical-agent detectors, ion mobility techniques have become popular for different purposes. Though ion mobility spectrometry was solely used as vapor sensor in the past decades, further developments in ionization techniques (especially electrospray ionization) now permit its routine use for the analysis of liquid samples. The coupling of ion mobility spectrometry with selective sample preparation techniques such as molecular-imprinted polymers, coupling with chromatographic techniques, the use of dopants, and application of selective ionization sources has led to an expanded number of applications in industrial and environmental analysis with ...

The Kubelka-Munk Diffuse Reflectance Formula Revisited

Abstract: We use an integral equation approach to finding the Kubelka-Munk (KM) diffuse reflectance formula and extend the result by finding the apparent path length and total intensity distribution inside an infinite, homogeneous, diffusely reflecting medium with isotropic scattering. We then expand the approach to three dimensions to show that the KM formula is correct for total diffuse reflectance when scattering, excitation, and detection are all isotropic. We obtain simple and exact results for the angular distribution of diffuse reflection and for the total diffuse reflectance when the incident light has an isotropic angular distribution, when it strikes at a single angle of elevation, and when it has the steady-state angular distribution. This work includes some results that employ Chandrasekhar's H function, so we also provide a program for the rapid evaluation of H. “[Supplementary material is available for this article. Go to the publisher's online edition of Applied Spectroscopy Reviews for the ...

Recent Progress on Infrared Photoacoustic Spectroscopy Techniques

Abstract: Analogous to most new methods in science, photoacoustic spectroscopy (PAS) grew out of an advance in technology, in this case the dramatic improvement in novel light sources, modulators, and acoustic detectors, as well as signal recovery electronics, which in turn was made possible by the development of modern PAS techniques. PAS is a promising technique that can be used to analyze and characterize a broad variety of objects (gaseous, solid, and liquid samples). In the present review, the recent development of infrared PAS limited to the general area of gas-phase analysis techniques since 1990 is summarized, with special emphasis on the development of new or enhanced analytical methodologies based on the use of the photoacoustic (PA) effect to improve the sensitivity of PAS by enhancing signal or reducing noise levels, with regard to PA systems, applications, and conclusions. The applications of these novel PA methods are mainly concerned with molecular spectroscopic, industrial, atmospheric, env...

Photoacoustic Instruments for Practical Applications: Present, Potentials, and Future Challenges

Abstract: Gas concentration monitoring by photoacoustic spectroscopy is reviewed from the point of view of practical applicability. Major challenges, which stem from the complexity of the measurement method, are thoroughly discussed and the possibility for long-term reliable and automatic measurements is demonstrated.

Determination of Trace Elements in Vegetable Oils and Biodiesel by Atomic Spectrometric Techniques—A Review

Abstract: The determination of trace elements in edible oils and biodiesel using atomic spectrometric methods is reviewed. Problems related to sample pretreatment for appropriate sample introduction and calibration are addressed as well as the strategies to overcome them. Recent trends aimed at simplifying sample manipulation are presented. The applications and scope of atomic absorption spectrometry (AAS), flame optical emission spectrometry (F-OES), inductively coupled plasma–optical emission spectrometry (ICP-OES), and inductively coupled plasma–mass spectrometry (ICP-MS) techniques for the determination of trace metals in edible oils and biodiesel are discussed, as well as some current instrumental new developments.

Terahertz Time-Domain Spectroscopy of Solid Samples: Principles, Applications, and Challenges

Abstract: Advances in ultrafast lasers and semiconductor technologies have facilitated access to the terahertz (THz) frequency range for spectroscopic and imaging purposes. THz time-domain spectroscopy (TDS) is commonly used to acquire spectral data having high signal-to-noise ratios (SNRs) over a broad range of THz frequencies. THz-TDS instrumentation is commercially available, thereby enabling novel applications of THz time-domain (TD) imaging and spectroscopy in a myriad of applications. This review gives a general description of the instrumentation available for collecting THz-TD data and focuses on measurements of solid samples. Measurement geometries useful for collecting THz-TD data from solid samples are reviewed and a summary is presented of the major applications to the analysis of solid samples related to security issues, as well as samples originating from the pharmaceutical industry, dental sciences, biological samples, and polymer materials. Emphasis is also given to analytical applications i...

Evolved Gas Analysis by Mass Spectrometry

Abstract: The analytical applications of the evolved gas analyses (EGAs) performed by mass spectrometry for the period extending from 2005 to 2010 are collected in this review. By EGA, the nature of volatile products released by a substance subjected to a controlled temperature program are determined on-line, with the possibility to prove a supposed reaction either under isothermal or under heating conditions.

Dielectric Barrier Discharge in Analytical Spectrometry

Abstract: Dielectric barrier discharge is a nonequilibrium plasma, and its industrial application has been on a large scale. Similarly, its prominent features of high dissociation ability at low working temperature and low power consumption, simple and adjustable configuration, ambient working conditions, and long lifetime are favorable for developing a wide array of analytical devices as well. This review addresses the basics of dielectric barrier discharge and emphasizes their analytical applications in analytical atomic spectrometry, chemiluminescence, gas chromatographic detectors, ion source for mass spectrometry, and ion mobility spectrometry with 103 references.

Recent Applications of Fourier Transform Infrared Spectrophotometry in Herbal Medicine Analysis

Abstract: Fourier transform infrared spectroscopy (FTIR) is a fast and nondestructive analytical method. Associated with chemometrics, it is a powerful tool for the pharmaceutical industry. It is becoming a suitable technique for analysis of herbal medicine. This review focuses on the recent developments and updates for the qualitative and quantitative analysis of herbal medicine using FTIR. Moreover, it can be implemented during herbal drug development, in production for process monitoring, or in quality control laboratories.

Application of FTIR Spectroscopy for Identification of Blood and Leukemia Biomarkers: A Review over the Past 15 Years

Abstract: Fourier transform infrared (FTIR) spectroscopy is an effective and nondestructive method for monitoring cellular alterations. Combining the advantages of FTIR spectroscopy with the challenge of cellular characterization, the main objective of this review is to collect information related to the spectroscopic identification of blood cells, focusing on specific biochemical features of leukemia cells detected through FTIR spectral analysis. Some interesting results obtained by different authors regarding human promyelocytic leukemia, white blood cells, chronic lymphocytic leukemia, and human peripheral blood mononuclear cells are presented. In addition, the characterization of two types of cells, namely, leukemia T and a healthy human blood cells, is reported and the identification of biochemical markers provides important information that, associated with clinical examination, can assist in the diagnosis of diseases.

Application of Infrared Photoacoustic Spectroscopy in Soil Analysis

Abstract: Soil analysis has become routine work for soil management and crop production. However, laboratory analysis–based determination of soil properties is expensive and time consuming, which is not suitable for precision agriculture. Infrared spectroscopy (IR) appears as an alternative and fast technique to measure soil properties and has had wide application; in particular, a new method called infrared photoacoustic spectroscopy (FTIR-PAS) has been applied in soil analysis. The soil infrared photoacoustic spectrum is more convenient to record; the spectra contain more useful information versus conventional reflectance spectroscopy, and it appears promising for identification of soil types and measure soil properties. The step-scan function of FTIR-PAS makes it possible to explore the soil microstructure in situ; furthermore, more sensible photoacoustic cells (PA), such as a quartz-enhanced PA cell, will make FTIR-PAS a strong tool for the study of soil science. The application of infrared photoacouti...

Quality Control of Honey Using Infrared Spectroscopy: A Review

Abstract: Honey is a carbohydrate-rich syrup and viscous fluid produced by honeybees (Apis mellifera) from the nectar of flowers that, by definition, does not include any other substances. Honey is produced primarily from floral nectars, and fructose and glucose are the major components. Overall, the chemical composition of honey varies depending on plant source, season, production methods, and storage conditions. Analytical methods applied to honey generally deal with different topics such as determination of botanical or geographical origin, quality control according to the current standards, and detection of adulteration or residues. Traditional chemical composition analysis and physical properties assessment are routinely performed in commercial trading of honey using time-consuming analytical methods that require considerable sample preparation and analytical skills. Spectroscopic techniques in the infrared (IR) wavelength region of the electromagnetic spectrum have been used in the food industry to monitor and evaluate the composition of foods and are becoming one of the most attractive and commonly used methods of analysis. This review discusses the use, with advantages and limitations, of IR spectroscopy technologies to evaluate and monitor the composition of honey.

Microplasma Technology and Its Applications in Analytical Chemistry

Abstract: This review article describes some existing microplasma sources and their applications in analytical chemistry. These microplasmas mainly include direct current glow discharge (DC), microhollow-cathode discharge (MHCD) or microstructure electrode (MSE), dielectric barrier discharge (DBD), capacitively coupled microplasmas (CC mu Ps), miniature inductively coupled plasmas (mICPs), and microwave-induced plasmas (MIPs). The historical development and recent advances in these microplasma techniques are presented. Fundamental properties of the microplasmas, the unique features of the reduced size and volume, as well as the advantageous device structures for chemical analysis are discussed in detail, with the emphasis toward detection of gaseous samples. The analytical figures of merit obtained using these microplasmas as molecular/elemental-selective detectors for emission spectrometry and as ionization sources for mass spectrometry are also given in this review article.

Two-Dimensional Correlation Analysis of Hydrogen-Bonded Systems: Basic Molecules

Abstract: This review provides information on application of two-dimensional (2D) correlation spectroscopy to studies of the molecular structure and hydrogen bonding in basic molecules and their binary mixtures with water. The first part of this review is an introduction to 2D correlation analysis and includes detailed description how to calculate the synchronous and asynchronous spectra from the raw experimental data. An appropriate pretreatment is widely discussed and the MATLAB codes to perform these operations are given. In the second part, the applications of 2D correlation spectroscopy for explorations of basic molecules like aliphatic alcohols, N-methylacetamide (NMA), diols, amino alcohols, carboxylic acids, and water in the pure liquid phases are reviewed. Finally, the 2D correlation studies of binary mixtures of basic molecules with water are discussed. It has been shown that an application of 2D correlation analysis to the complex spectra makes it possible to obtain the information not readily s...

Lanthanide-Sensitized Luminescence as a Promising Tool in Clinical Analysis

Abstract: The recent applications and novelties of lanthanide-sensitized luminescence (LSL) as a detection technique in clinical analysis are here reviewed. In LSL, lanthanide ions form complexes with organic compounds; in these complexes, the energy absorbed by the organic chromophore (usually the analyte) at its characteristic excitation wavelength is transferred to a triplet state of the molecule and then transferred to a resonance level of the lanthanide ion, which finally emits luminescence at its particular emission wavelength. The characteristics of this process will be reviewed and particular attention will be paid to the development of automatic methods of analysis, fluorescence probes, or flow-through optosensors, due to their potential applications in clinical analysis. A critical discussion of the advantages and handicaps of each analytical method is done and the trends of analytical chemistry in this research field are also presented.

The Application of 7-Chloro-4-nitrobenzoxadiazole (NBD-Cl) for the Analysis of Pharmaceutical-Bearing Amine Group Using Spectrophotometry and Spectrofluorimetry Techniques

Abstract: Many papers have been presented in recent years regarding the field of application of 7-chloro-4-nitrobenzoxadiazole (NBD-Cl) as a fluorogenic and chromogenic reagent for the determination of pharmaceutical amines using spectrophotometry and spectrofluorimetry techniques. In this review article, various spectrophotometric and spectrofluorimetric methods using NBD-Cl as a labeling reagent for determination of pharmaceutical amines are covered. The application of these methods for the determination of drugs in pharmaceutical and real samples is also discussed.

Vibration Spectra and Structural Characteristics of Ba[(Zn1-x Mg x )1/3Nb2/3]O3 Solid Solutions

Abstract: The Ba[(Zn1-x Mg x )1/3Nb2/3]O3 (BZMN, x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) solid solution ceramics were synthesized by the conventional solid-state reaction method. Vibration spectra (Raman spectroscopy and Fourier transform far-infrared reflection [FTIR] spectroscopy) and X-ray diffraction (XRD) were employed to evaluate the correlation between crystal structures and vibration modes of these solid solutions as a function of Zn2+ ions replaced by Mg2+ ions. Spectroscopic and structural data show sensitivity to the sample structural evolution with Mg2+ concentration, and a 1:2 ordered structure appears for Mg-rich samples where x ≥ 0.6. The Ba[(Zn0.4Mg0.6)1/3Nb2/3]O3 has a 1:2 ordered monoclinic unit cell, which is distorted by the antiphase tilting of the oxygen octahedra. The phonon modes were assigned, and a correlation of phonon vibrations with the microstructure was found. The position and width of the phonon modes were determined and correlated to the ionic radii, mass, and tolerance factors f...

From mg/kg to pg/kg Levels: A Story of Trace Element Determination: A Review

Abstract: Determination of the trace elements in a variety of environmental samples is of great importance. Most elements, including iron, calcium, and selenium, are crucial for the regulation of human mechanisms, and many others, like lead and cadmium, are toxic even at trace levels. Some elements, like selenium, have a narrow margin of safety. Hence, determination of elements at trace levels is crucial in any matrix related to humans. Trace element determination requires sufficiently sensitive procedures to monitor trace levels. This review aims to highlight not only the development in instrumentation for ultratrace element determination in variety of matrices but the application of developed techniques. Advantages and disadvantages of the techniques are also discussed.

Ab Initio Calculations and Raman and SERS Spectral Analyses of Amphetamine Species

Abstract: For the first time, the differences between the spectra of amphetamine and amphetamine-H+ and between different conformers are thoroughly studied by ab initio model calculations, and Raman and surface-enhanced Raman spectroscopy (SERS) spectra are measured for different species of amphetamine. The spectra of amphetamine and amphetamine-H+ samples were obtained and assigned according to a comparison of the experimental spectra and the ab initio MO calculations, performed using the Gaussian 03W program (Gaussian, Inc., Pittsburgh, PA). The analyses were based on complete geometry minimization of the conformational energy of the S-plus-amphetamine molecule and the S-plus-amphetamine-H+ ion. The harmonic frequency calculations provide information about the characteristic features of the Raman spectra and the nature of the bonding in the molecule. It is concluded that vibrational bands from salt anions with internal bonds (sulfates, hydrogen phosphates, etc.) need to be taken into account when employi...

A Review of Tungsten Coil Electrothermal Vaporization as a Sample Introduction Technique in Atomic Spectrometry

Abstract: Tungsten coil electrothermal vaporization has served as an alternative sample introduction method in atomic spectroscopy for some time and is easily employed in a laboratory because of its mass production, ease of use, and small requirement for power. This review will focus on the use of the tungsten coil as an electrothermal vaporization sample introduction source in atomic absorption, emission, and fluorescence spectrometry over the past decade. Analyzed samples have both biological and industrial significance, illustrating the versatility of the technique. Since its conception 40 years ago, tungsten coil electrothermal vaporization continues to provide users with innovative options for spectroscopic analysis.

Use of Crustacean Shells for Uptake and Removal of Metal Ions in Solution

Abstract: The use of crustacean shells, in particular crab shells, for the removal of metal ions in solution is described. Research studies found in the literature on the ability of the shells, effect of particle size, pH, competitive studies in mixtures of metals, application to real samples such as acid mine drainage, and use of the shells in a column are presented. The major component of the shells that allows uptake to occur is chitin. Several mechanisms are proposed for uptake. There are conflicting accounts in the literature on such areas as the effect of pH, flow rate, and particle size.

Fluorescence Correlation Spectroscopy (FCS): A Promising Tool for Biological Research

Abstract: Fluorescence correlation spectroscopy (FCS) is an important biophysical technique. FCS is currently being used in many areas of biology to solve several scientific problems. Its properties such as detection at the single molecular level, higher sensitivity, and use of lower sample volume make FCS a promising molecular diagnostic tool. The promising applications of FCS extend from DNA kinetics/dynamics studies to the comprehensive understanding of receptor–ligand interactions. In this article, we review various promising biological applications of FCS.

H-Point Standard Addition Method (HPSAM) in Simultaneous Spectrophotometric Determination of Binary Mixtures: An Overview

Abstract: The H-point standard addition method (HPSAM) is a modification of the standard addition method that transforms the incorrigible error resulting from the presence of a direct interferent in the determination of an analyte into a constant systematic error. This error can then be evaluated and eliminated. The method was established for resolving strongly overlapping spectra of two analytes and permits both proportional and constant errors produced by the matrix of the sample to be corrected directly. The technique is based on the principle of dual-wavelength spectrophotometry and the standard addition method. The application of the method requires only two wavelengths, and the analytical signal caused by one of the species should be constant and that of the other should differ as much as possible. This overview discusses both the theoretical and practical aspects of HPSAM applications.

Contribution to Automation for Determination of Drugs Based on Flow-Through Optosensors

Abstract: The contribution of solid-phase spectroscopy (SPS) from its first conception (batch mode) to developments based on implementing SPS with flow analysis methodologies, flow-through optosensors (FTOs), is discussed. This article reviews the technical status of these sensors and addresses works of different flow technologies for the detection of drugs in pharmaceutical and clinical samples. In order to give readers insight into the features and the potential of FTO, relevant examples of strategies and types of configuration are studied. The reports cited show the characteristics of these systems, including high sensitivity and selectivity, easy automation, less amount of reagent used, and low cost of the equipment. Finally, the advantages and disadvantages of the different flow methodologies described as well as a comparison with chromatographic techniques are critically highlighted.

A Simple Method for Initial Condensed-Phase Combustion Reactions Predictions

Abstract: Combustion modeling of energetic materials has undergone a tremendous amount of development in recent years. Gas-phase combustion properties predictions are possible and have been shown to agree with experimental results. For solid energetic materials, the gasification reaction products must be determined if gas-phase models are to be applied. The majority of actual models still involve a guessing step for gasification products due to the lack of knowledge in the condensed phase. Quantum dynamical calculations are presently the only way to predict initial condensed-phase reactions but require tremendous computing power, thus limiting their application. In this work, an empirical method that uses spectroscopic measurements of energetic molecules as the source for the complete modal molecular picture is presented. The method enables a qualitative prediction of the first combustion reaction in the condensed phase. The application of the methods with nitrocellulose and nitroguanidine shows that it pr...

Imaging Mass Spectrometry

Abstract: Mass spectrometry has been a valuable resource in science for decades. The ability to know exact masses of analytes allows for a more precise knowledge of the composition of materials. The technique has evolved to allow analysis of increasing numbers compounds in increasingly complex environments. Selected examples of biological applications of mass spectrometry imaging are discussed, in addition to a variety of tissue imaging and other medical applications. A number of inorganic applications are also described. Finally, a conclusion regarding the prospects for the future of imaging mass spectrometry completes this brief review.