A Review of Recent Near-Infrared Research for Wood and Paper (Part 2)

Abstract: This review article introduces recent technical and scientific reports on near-infrared (NIR) spectroscopy in the wood and paper industry, which have increased during the last decade. Many researchers have reported that the NIR technique is useful for detection of both chemical and physical properties of wood materials and has been widely used in cases where the characteristic cellular structure of the material is retained. With regard to application of NIR spectroscopy to pulp and paper, many publications have reported its potential as an on-line measurement technique during paper-making process control. NIR spectroscopy is considered fundamental in applied research on wood and paper. Utilization of NIR spectroscopy in the wood and paper industry should take into account its applicability and limitations as a nondestructive technique.     

A Review of Recent Near Infrared Research for Wood and Paper

Abstract

This review article introduces recent technical and scientific reports in terms of near infrared (NIR) spectroscopy in the wood and paper science and industry, where interest has increased during the last couple decades. Many researchers reported the NIR technique was useful to detect multi information in both chemical and physical properties of wood materials, although it was widely used in a state where characteristic cellular structure was retained. In the case of application of NIR spectroscopy to pulp and paper, many publications have pointed out its high probability as online measurement techniques during paper‐making process control. Arguments referred to the importance of NIR spectroscopy as fundamental and applied research of wood and paper.     

Uses of Near-Infrared Spectroscopy in Pharmaceutical Analysis

Abstract

Near-infrared (near-IR, NIR) spectroscopy has been a regularly used technique in agriculture and textile manufacturing for some years [1–61. However, the pharmaceutical industry has been slow to accept near-JR as an everyday analytical process. One reason may be its lack of primary absorption bands. All NIR absorbances are overtones of bands originating in the midrange infrared spectrum (4000–17000 nm). In addition, most of the near-JR spectrum of organic compounds (800–3500 nm) is attributable to combinations of the aforementioned over-tones. These “shortcomings” are more than compensated for by the attributes of near-IR instrumentation. Several excellent reviews have recently been published on the theory and instrumentation involved in near-IR reflectance analysis (NIRA) [7–10].     

NIR Spectroscopy and Imaging Techniques for Evaluation of Fish Quality—A Review

Abstract

Fish is a highly perishable product and it is particularly important to pay attention to its quality changes. Maintenance of the high quality of fish and fishery products necessitates development of means for precise and rapid quality evaluation. Near-infrared (NIR) spectroscopy and imaging techniques are proven technologies that can provide useful information for the estimation of quality attributes in fish and fishery products due to fast speed, noninvasiveness, ease of use, and minimal sample preparation. The aim of this review is to communicate perspectives and aspects relating to NIR spectroscopy and imaging techniques with regard to evaluation of chemical composition (fat, protein, and moisture), microbiological (freshness, spoilage, and nematodes), and sensory (flavor, texture, and color) attributes of fish and fishery products. Moreover, the usefulness of NIR spectroscopy and imaging techniques for fish authentication and classification are presented. Finally, some viewpoints on the current situation and suggestions for future research directions are proposed.     

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.     

Recent Advances in Near-Infrared Reflectance Spectroscopy

Abstract

A proliferation of applications for near-infrared reflectance spectroscopy has been driven by recent advances in instrumentation and chemometrics. These include the development of smaller, portable instruments with no moving parts, suitable for process environments, and new data treatments and calibration algorithms to model nonlinear relationships between spectra and chemical constituents. The intent of this review is to focus on recent developments in near-infrared reflectance spectroscopy, including chemometrics and new applications of NIR reflectance in several diverse fields, rather than to address indepth the historical development of NIR. Certain topics, such as chemometrics, deserve a comprehensive review by themselves, and the reader is urged to consult the original sources for greater depth. As a newcomer to the field, I have attempted to present those topics which may be of greater interest to the novice.     

Applications of Near‐Infrared Spectroscopy in Refineries and Important Issues to Address

Abstract

This review primarily concerns NIR (near‐infrared) applications in refineries. Initially, this article reviews the fundamental aspects for analysis of hydrocarbon mixture by NIR spectroscopy, such as spectral sensitivity in various spectral regions, signal‐to‐noise ratio, and spectral resolution. Though there are applications of NIR to diverse petroleum products, this review subsequently focuses only on applications to four major products: gasoline, diesel, naphtha, and crude oil, which are the most interesting from a refiner's viewpoint. In each application, discussion of important issues to consider for proper and optimal NIR measurement is included. Finally, the issue of calibration transfer is discussed.     

Rapid evaluation of the salt content of canned sardines in brine using near-infrared diffuse reflectance spectroscopy

ABSTRACT

In this study, the evaluation of the salt content of canned sardines in brine using near-infrared (NIR) spectroscopy with a Fourier transform NIR spectrometer in diffuse reflectance mode over a range of 12,500–4000?cm^?1 was investigated. The reference salt content of the samples was measured using an autotitrator. The optimum partial least squares regression model was developed using vector normalization spectra in the ranges of 9403.8–5446.3?cm^?1 and 4605.4–4242.9?cm^?1 with seven factors. The model provided a coefficient of determination for a prediction of 0.82, a root mean square error of prediction of 0.069%, a bias of ?0.019%, and a ratio of prediction deviation of 2.5. NIR spectroscopy has great potential as an alternative method for measuring the salt content of canned sardines in brine, and the calibration model is useful for the off-line quality control of canned sardines in brine processing. In addition, the oxygen–hydrogen bond stretch and deformation and the carbon–hydrogen bond stretch and deformation had obvious effects on the prediction of the salt content of canned sardines in brine.     

The Nanosecond Laser Flash Photolysis (LFP) Transient Spectra of Aqueous CCl4 Solution

Abstract

The Raman spectrum of polycrystalline vaterite is presented and compared to spectra of calcite and aragonite, the other two common CaCO₃ polymorphs; Raman spectroscopy easily distinguishes between these three polymorphs. An important feature of the Raman spectrum of vaterite is splitting of both the ν₁ and ν₄ peaks. The splitting of the ν1 peak implies two distinct site symmetries for the CO₃ ^?2 groups. A definitive crystal structure determination of vaterite is not yet available, but none of the three proposed structures for vaterite show such a feature.     

An Innovative Measurement of Extractable Proteins from Concentrated Latex Containing Eggshell Calcium Oxide Compounds by Near-Infrared Spectroscopy

ABSTRACT

Near-infrared reflectance (NIR) spectroscopy, in the spectral range of 1100–2500 nm, was used to measure the amount of the directly extractable proteins (EP) where a small amount can cause a latex allergy to patients. The NIR spectra revealed an amino or a peptide (N-H) of the extractable proteins from the concentrated rubber latex added with sodium dodecyl sulphate (SDS) and calcium chloride, the latter being obtained from the pyrolysis of eggshells at 900°C for 2 hr and dissolving in 2 M HCl. The extractable proteins measured by NIR are equal to 5306.58 ± 1727.00 µg/g (0.53%) close to the value obtained by the modified Lowry method, which is 5566.02 ± 717.39 µg/g (0.56%). A partial least square regression model (PLSR) of the NIR spectra and the extractable protein contents yields a correlation coefficient of .72, a root mean square error of calibration (RMSEC) of 1298 µg/g, and a small bias value of ?0.0002 µg/g. The absorbance peaks at the wavelengths of 1520 nm and 1980 nm are related to the first overtone N-H (υ₁N-H) and the asymmetric combination of N-H, respectively. Furthermore, the absorbance peaks at the wavelengths of 1450 nm and 1920 nm correspond to the first overtone of O-H (υ₁O-H) of the concentrated latex compounds. The results demonstrate the NIR spectroscopy potential as a fast and noninvasive measurement technique.     

Hyperspectral Imaging Applications in Agriculture and Agro-Food Product Quality and Safety Control: A Review

Abstract

In this review, various applications of near-infrared hyperspectral imaging (NIR-HSI) in agriculture and in the quality control of agro-food products are presented. NIR-HSI is an emerging technique that combines classical NIR spectroscopy and imaging techniques in order to simultaneously obtain spectral and spatial information from a field or a sample. The technique is nondestructive, nonpolluting, fast, and relatively inexpensive per analysis. Currently, its applications in agriculture include vegetation mapping, crop disease, stress and yield detection, component identification in plants, and detection of impurities. There is growing interest in HSI for safety and quality assessments of agro-food products. The applications have been classified from the level of satellite images to the macroscopic or molecular level.     

Near Infrared Spectroscopy of Benzoic Acid Adsorbed on Montmorillonite

ABSTRACT

The adsorption of benzoic acid on both sodium and calcium montmorillonites has been studied by near infrared spectroscopy complimented with infrared spectroscopy. Upon adsorption of benzoic acid, additional near-infrared bands are observed at 8665 cm^?1 and assigned to an interaction of benzoic acid with the water of hydration. Upon adsorption of the benzoic acid on Na-Mt, the NIR bands are now observed at 5877, 5951, 6028, and 6128 cm^?1 and are assigned to the overtone and combination bands of the CH fundamentals. Additional bands at 4074, 4205, 4654, and 4678 cm^?1 are attributed to CH combination bands resulting from the adsorption of the benzoic acid. Benzoic acid is used as a model molecule for adsorption studies. The application of near-infrared spectroscopy to the study of adsorption has the potential for the removal of acids from polluted aqueous systems.     

Fourier‐Transform Near‐Infrared Spectroscopy as a Tool for Olive Fruit Classification and Quantitative Analysis

Abstract

The potential of diffuse reflectance near‐infrared spectroscopy combined with pattern recognition to discriminate between olives (Olea europaea L.) of different qualities has been tested. The sample set was formed of sound olive fruits and those showing the most common alterations of olives, which lead to decreased oil quality, namely freeze damages, harvest after falling on the ground, fermentation due to prolonged storage time, and olive tree diseases. Near‐infrared (NIR) spectra were recorded between 9900 and 4100 cm^?1. Preliminary studies of the data set structure were performed using hierarchical cluster analysis and principal component analysis. Discriminant analysis provided prediction abilities of 100% for sound, 79% for frostbite, 96% for ground, and 92% for fermented olives using a leave‐a‐fourth‐out cross‐validation procedure. Quantification of oil and water content in the olives was also approached by using partial least squares (PLS) regression. Results, in terms of predictive ability using a leave‐one‐out cross‐validation, were compared for calibration using the whole sample set and calibrations for the sound and damaged samples separately. Relative errors of prediction using all samples were 7.2% and 3.4% for oil content and humidity, respectively. Using only sound samples, relative errors of prediction of 3.8% and 2.8% for oil and water content, respectively, were obtained. Thus, better accuracy could be achieved when classification of the olive samples prior to quantitative analysis was performed. These results demonstrate the utility of NIR spectroscopy to differentiate olives of different qualities. Using NIR, a fast selection of sound olives in a quality‐orientated production facility becomes feasible.     

Near‐infrared Raman spectroscopy for gastric precancer diagnosis

Raman spectroscopy is a molecular vibrational spectroscopic technique that is capable of optically probing the biomolecular changes associated with neoplastic transformation. The purpose of this study was to apply near‐infrared (NIR) Raman spectroscopy for differentiating dysplasia from normal gastric mucosa tissue. A total of 65 gastric mucosa tissues (44 normal and 21 dysplasia) were obtained from 35 patients who underwent endoscopy investigation or gastrectomy operation for this study. A rapid NIR Raman system was utilized for tissue Raman spectroscopic measurements at 785‐nm laser excitation. High‐quality Raman spectra in the range of 800–1800 cm⁻¹ can be acquired from gastric mucosa tissue within 5 s. Raman spectra showed significant differences between normal and dysplastic tissue, particularly in the spectral ranges of 850–1150, 1200–1500 and 1600–1750 cm⁻¹, which contained signals related to proteins, nucleic acids and lipids. The diagnostic decision algorithm based on the combination of Raman peak intensity ratios of I₈₇₅/I₁₄₅₀ and I₁₂₀₈/I₁₆₅₅ and the logistic regression analysis yielded a diagnostic sensitivity of 90.5% and specificity of 90.9% for identification of gastric dysplasia tissue. This work demonstrates that NIR Raman spectroscopy in conjunction with intensity ratio algorithms has the potential for the noninvasive diagnosis and detection of precancer in the stomach at the molecular level. Copyright © 2009 John Wiley & Sons, Ltd.     

Use of Infrared Microspectroscopy in Plant Growth and Development

Abstract

Infrared microspectroscopy (IMS) has emerged as a key technique for the study of plant growth and development. The combination of IMS and synchrotron radiation has enabled researchers to analyze plant development at a cellular level. The spatial distribution of functional groups in plant tissue can be determined by the “chemical imaging” ability of IMS. Attenuated total reflectance (ATR) and polarized IR spectroscopies in combination with IMS makes sampling rapid and easy, providing direct analysis in situ. This review covers applications of IMS to study cell wall architecture and the major cell wall components: lignin, cellulose, and polysaccharides; applications for agricultural and feed products; and changes to plant structure due to biotic and abiotic stressors.     

Solid‐State NMR Studies of Pharmaceutical Systems

Abstract

High‐and low‐resolution solid‐state nuclear magnetic resonance (SSNMR) applications to the study of pharmaceuticals are reviewed. Examples are shown involving the use of mono‐and bidimensional SSNMR techniques based on different nuclear interactions and the measurement of several nuclear parameters, such as chemical shifts, line widths, and relaxation times (T₁, T₂, T_1ρ). The systems investigated include pure active pharmaceutical ingredients (APIs), substances used as drug excipients, and solid dispersions formed by APIs and excipients, up to final drug formulations. The most important aspects treated concern structural, dynamic, and morphological properties, and, in particular, identification, characterization, and quantitation of polymorphs and related forms, conformational and crystalline packing behavior, amorphous phase properties and stability, effects of drug processing, molecular motions, API‐excipient and excipient‐excipient chemical and physical interactions, and phase mixing in heterophasic systems.     

马来酰肼多形态的太赫兹光谱研究

分子的多形态(多晶型)是指化学组成相同但存在不止一种晶体形式的物质.这些多形态广泛存在于自然界中,其中药物的多形态尤其普遍.这些药物多形态虽然具有相同的化学分子组成,但其理化性质却存在差异,最终会导致药物作用功能的不同.近年来,随着太赫兹(THz)辐射源的产生方式成为一种常规技术后,太赫兹时域光谱技术(THz-TDS)...     

近五年我国近红外光谱分析技术研究与应用进展

评述了我国近五年来(2009年—2013年)近红外光谱分析技术的研究与应用进展,内容涉及软硬件研发、方法研究、以及诸多领域的应用开发等方面,并对今后我国近红外光谱技术的发展方向提出了建议。引用文献209篇。     

Pharmaceutical polymorphs quantified with transmission Raman spectroscopy

The quantification of polymorphs in dosage forms is important in the pharmaceutical industry. Conventional Raman spectroscopy of solid‐state pharmaceuticals may be used for this, but it has some limitations such as sub‐sampling and fluorescence. These problems can be mitigated through the use of transmission Raman spectroscopy (TRS). The efficacy of TRS measurements for the prediction of polymorph content was evaluated using a ranitidine hydrochloride test system. Four groups of ranitidine hydrochloride‐based samples were prepared: three containing form I and II ranitidine hydrochloride and microcrystalline cellulose (spanning the ranges 0–10%, 90–100% and 0–100% form I fraction of total ranitidine hydrochloride), and a fourth group comprising form I ranitidine hydrochloride (0–10%) spiked commercial formulation. Transmission and conventional Raman spectroscopic measurements were recorded from both capsules and tablets of the four sample groups. Prediction models for polymorph and total ranitidine hydrochloride content were more accurate for the tablet than for the capsule systems. TRS was found to be superior to conventional backscattering Raman spectroscopy in the prediction of polymorph and total ranitidine hydrochloride content. The prediction model calculated for form I content across the 0–100% range was appropriate for process control [ratio of prediction to deviation (RPD) equal to 14.62 and 7.42 for tablets and capsules, respectively]. The 10% range calibrations for both form I and total ranitidine hydrochloride content were sufficient for screening (RPDs greater than 2.6). TRS is an effective tool for polymorph process control within the pharmaceutical industry. Copyright © 2011 John Wiley & Sons, Ltd.     

Awakening the Dumb Site to Realize Ultra-Broadband NIR Phosphor

Near-infrared (NIR) light sources have gained immense popularity in recent years due to their wide range of applications in various fields, including spectroscopy and biomedical imaging. However, the limited emission bandwidth of NIR phosphors is a significant bottleneck in their development. Here, a novel strategy is reported to broaden the emission bandwidth of NIR phosphors by awakening the dumb site. Na₄M₃Ta(PO₄)₆: Cr³⁺ (M = Al³⁺, Ga³⁺, In³⁺) phosphor is synthesized, which exhibits a greatly broadened bandwidth from 134 to 232 nm. Structural and spectral analysis reveals that the NaO₆ octahedral site has a severe t_2g-type distortion, making it a dumb site for Cr³⁺. By introducing larger In³⁺ at the M site, the angular distortion at the NaO₆ site decreases to the normal range, enabling the luminescence of Cr³⁺ again. Along with the broadened bandwidth, the emission peak also redshifts from 802 to 977 nm, giving advantages in NIR spectroscopy applications. Interestingly, the awakened luminescence at the NaO₆ site shows even better luminescence properties than the original M/TaO₆ octahedral site. These findings reveal a novel insight into the luminescence of Cr³⁺ at the octahedral site, which could potentially revolutionize the design of NIR phosphors.