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.     

Near-Infrared Spectroscopy: Effective Tool for Screening of Polymorphs in Pharmaceuticals

Abstract

Near-infrared (NIR) spectroscopy has emerged as an important technique for the screening and characterization of polymorphs in pharmaceuticals. Polymorphism, the ability of a substance to exist in two or more crystalline phases having different physicochemical and biopharmaceutical parameters, has attracted pharmaceutical scientists due to the patentability of new forms. Transformation of the solid phase due to polymorphic changes during manufacturing and storage may lead to formulation hurdles. Vibrational spectroscopy, particularly NIR spectroscopy, is a widely used technique for polymorphs screening in drug development processes and has emerged as a process analytical technology tool. In this review, a brief overview of NIR spectroscopy, chemometric tools, and polymorphs screening of pharmaceuticals using NIR spectroscopy is presented. Recent developments in NIR spectroscopy instrumentation are also discussed.     

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].     

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.     

New Approaches and Recent Advances on Characterization of Chemical Functional Groups and Structures,Physiochemical Property,and Nutritional Values in Feedstocks and By-Products: Advanced Spectroanalytical and Modeling Investigations

Abstract: Molecular spectroscopy technique, a rapid and noninvasive analytical technique, is able to reveal biomaterials’ structural features. However, to date, this technique is seldom used in the biofuel and bioethanol processing industry. This article aims to provide research progress and updates on molecular spectroscopy of feedstocks and coproducts from biofuel/bioethanol processing and to show how to use this molecular technique to study the molecular structure, chemical functional groups, and physiochemical properties of feedstocks and coproducts from biofuel processing and how structural changes affect nutrient availability.     

SIMCA法判别分析木材生物腐朽的研究

木材是一种生物质材料,容易受到各种微生物的危害,生物腐朽可以迅速导致木材结构的破坏,因此,对木材生物腐朽的快速、准确地检测或鉴定具有重要意义。近几年来,近红外光谱和SIMCA方法正被用于识别或检测食品、药品和农产品等研究中,因此,本研究尝试利用近红外光谱结合SIMCA方法来检测木材的生物腐朽。研究结果表明,应用近红外光谱和SIMCA方法能有效地判别木材的生物腐朽类型,通过培训集样本建立的基于PCA分析的SIMCA判别模型对未腐朽、白腐和褐腐三种类型样本进行回判,判别准确率分别为100%, 82.5%和100%;而对未知腐朽类型的样本(包括未腐朽、白腐和褐腐样本),判别准确率分别为100%, 85%和100%;SIMCA方法对未腐朽和褐腐类型的判别准确率均达到100%,但对白腐样本都有错判,造成这种错判的主要原因可能是由于样本包括的信息不够丰富以及腐朽初期白腐和褐腐试样的性质差异太小等。     

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.     

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.     

木材中的水分及其近红外光谱分析

水分是木材的重要特征之一,用近红外光谱分析木材性质,必须考虑水分对预测结果的影响。文章分析了不同含水率状态下木材在近红外光谱区的吸收特性;用近红外光谱法预测木材中的水分含量,相关系数为0.99,校正标准偏差SEC和预测标准偏差SEP分别是0.041和0.043;通过在不同含水率(7%,12%,20%,30%,60%)状态下采集近红外光谱与固定含水率下的木材密度建立关联,结果表明,利用近红外光谱技术可以在不同含水率下采集近红外光谱来预测木材气干密度。     

Laser spectroscopy of free molecular oxygen dispersed in wood materials

The recently introduced Gas in Scattering Media Absorption Spectroscopy (GASMAS) technique is applied to the study of various wood samples. Molecular oxygen in the pores of the strongly scattering material is detected using diode laser spectroscopy around 760 nm. Diffuse light propagation in these media is studied by time-dispersion measurements. Furthermore, anisotropy related to the fibre structure of wood and gas diffusion properties are studied. Promising extensions of the experiments are discussed. PACS 42.55.Px; 42.62.Fi; 81.05.Rm; 81.70.Fy; 87.64.Cc     

A Review of Online Real-Time Process Analyses of Melt-State Polymer Using the Near-Infrared Spectroscopy and Chemometrics

Abstract

This review describes the online process monitoring of the melt-state polymer by near-infrared (NIR) spectroscopy and chemometrics. The spectra of linear low-density polyethylene (LLDPE), random polypropylene (RPP), block polypropylene (BPP), and ethylene-vinylacetate (EVA) copolymer in melt states measured by an online monitoring system with a Fourier transform near-infrared spectrometer are discussed. The calibration models for the density of LLDPE, the content of ethylene copolymers in RPP and BPP, and vinylacetate concentration (VA) in EVA copolymers using partial least squares regression are reported. The continuous monitoring of the LLDPE density at the real plant is described as an example of online monitoring using NIR spectroscopy and chemometrics. For the precise prediction of VA in EVA, a combination method using regression and discrimination was inducted. Three compensation methods for the effect of the temperature change in the RPP and BPP samples are shown. Conventional calibration transfer methods are introduced, and a practical calibration transfer method using two samples and its performance are reported using BPP and RPP spectra. Moreover, the possibility of a calibration correction method using one sample for the realization of long-term traceability is indicated by the example of the relocation.     

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.     

Differential scanning calorimetric investigations of naturally dehydrated aqueous sucrose solutions

Abstract

Differential scanning calorimetric investigations have been conducted on sucrose solutions for temperatures T<?100°C and in the sucrose concentration range 74 < c < 97. A novel method is adopted for sample preparation. For c > 92, the room temperature phase is amorphous, as indicated by its x-ray diffraction pattern. A melting transition is reported for the first time for these concentrations. A second-order phase transition is recorded for T < 0°C, which is clearly observed only during heating cycles, indicating a continuous phase transition during cooling. These transitions have not been reported so far, suggesting that the phase formed due to the procedure adopted for sample preparation may be different from that reported in the literature.     

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.     

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.     

光谱预处理对近红外光谱预测木材纤维素结晶度的影响

木材纤维素结晶度是木质材料的一个重要性质,它与树木的生长特性、结构与化学组成均有密切关系,并对木材的杨氏模量、尺寸稳定性、密度和硬度等具有重要的影响,文章研究了利用近红外光谱结合多变量数据分析技术对人工林木材纤维素的结晶度进行预测的能力。本研究从人工林湿地松木粉试样的表面采集近红外漫反射光谱,并利用X射线衍射法测定了木材纤维素的结晶度。研究表明,采用一阶导数和二阶导数光谱预处理没有提高近红外模型的预测效果,而采用原始光谱的预测效果最好,预测值与X射线衍射测定值的相关系数r可以达到0.950,各项预测误差值较低, 说明采用近红外光谱结合多变量数据分析方法建立的结晶度预测模型具有理想的预测能力。     

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.     

PLS-DA法判别分析木材生物腐朽的研究

利用近红外光谱结合PLS-DA判别分析方法可用于食品、药品和农产品等的快速识别或检测,因此,研究利用近红外光谱结合PLS-DA方法来检测木材的生物腐朽。研究结果表明：应用近红外光谱结合PLS-DA方法对培训集样本建立的判别模型,其校正及验证结果与实际分类变量的相关系数均超过0.94,SEC和SEP都低于0.17; 利用模型对未参与建模的样本进行检测,发现该模型对未腐朽、白腐和褐腐三种类型样本的判别准确率均为100%(偏差均小于0.5); 与SIMCA法相比,PLS-DA法对木材生物腐朽样本的判别准确率更高,说明应用近红外光谱结合PLS-DA方法能快速地检测到木材的生物腐朽,并能准确地判别出木材的生物腐朽类型。     

Study of Water Uptake in Whole Grain Barley by Two-Dimensional Correlation Near-Infrared Spectroscopy

This study reports the use of near-infrared (NIR) reflectance spectroscopy combined with two-dimensional correlation (2D-COS) spectroscopy to monitor the effect of soaking and water uptake by the barley endosperm (Hordeum vulgare, L). The synchronous 2D-COS maps derived from the NIR spectra of barley endosperm showed similarities that could be explained by the regions in the spectra associated with water as well as with the biochemical and biophysical changes as a consequence of the water uptake by the grain. The results also demonstrated the potential of 2D-COS combined with NIR spectroscopy as an analytical tool to study changes in the biophysical characteristics of whole barley during steeping or soaking. This method can be used to obtain information about the effect of water uptake in other chemical characteristics of the endosperm of cereal grains.     

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.