近红外光谱技术在中药栀子渗漉液理化指标快速分析中的应用研究

用声光可调滤光器(AOTF)-近红外(NIR)光谱法在线分析栀子渗漉液密度及栀子苷含量。在线收集栀子渗漉液样品,建立栀子渗漉液的含量、比重数据库,同时采集近红外光谱图谱,用偏最小二乘(PLS1)法分别建立NIR光谱与含量、比重数据之间的校正模型,并对在线过程中收集的预测集样品进行含量预测来验证所建模型。结果表明,渗漉液NIR光谱与含量、比重数据之间的校正模型相关系数R2分别为0.956 0和0.978 2,外部样品预测平均相对偏差分别为0.09%,2.84%;该方法精密度RSD分别为0.06%,2.96%;稳定性RSD分别为0.63%,1.89%;预测回收率分别为100.0%,99.9%。近红外光谱技术在栀子渗漉液密度及淫羊藿苷含量分析中具有快速、直接、多成分同时测定,并能实现现场分析。     

近红外光谱在油品快速分析中的应用

各项性能指标合格的油品是用油机械正常运行的前提和保证。因此,油品性质的快速检测具有重要的经济和军用价值。阐述了傅立叶变换近红外光谱技术测定油品多项物理性质的原理,介绍了其与化学计量学相结合进行油品快速分析的方法,综述了近红外光谱技术在油品快速分析领域中的应用现状,最后展望了其发展方向。     

近红外光谱技术在药物分析中的应用

近红外光是介于可见光和中红外光之间的电磁波,根据美国实验和材料检测协会(ASTM)的定义是指波长在780~2 526nm的电磁波,通常分为近红外短波和近红外长波。近红外光谱属于分子振动光谱的倍频和主频吸收光谱,穿透力较强。近红外光谱分析技术是大型化工、食品加工、制药等领域生产所必须的重要分析技术之一。阐述了近红外光谱技术在药物分析中的应用及该技术的特点和分析方法原理。     

近红外光谱在线分析技术将优化乙烯生产工艺

针对乙烯生产过程中常规分析不能满足装置优化操作要球的现状,在实验考察的基础上,介绍了现代近红外光谱技术在乙烯生产中可以完成一些分析项目,列出了部分实验结果,分析了该技术在乙烯工业中的应用及对工艺条件优化所起的作用。     

浅谈近红外光谱分析技术在油品分析中的应用

自上世纪八九十年代起,近红外光谱分析技术已经成为对化学化工产品进行分析测试技术中发展最快的技术之一。现在的近红外光谱分析技术已经实现了红外光谱分析技术、化学测量分析技术与基础分析技术的相互统一,在三种测量技术有机结合的基础上可以高速高效地对各种化学化工样品进行性能和质量的分析。目前,近红外光谱分析技术已经广泛在炼油过程中的油品分析过程中得到广泛使用,通过利用此技术间接测定油品中的物理数值和化学数值,再通过三种近红外光谱分析的三种技术的相互结合运用更准确地对油品成分进行分析。就目前计算机技术发展速度而言,近红外光谱分析技术是对油品质量进行分析既方便又快捷的分析手段,并随着科学技术的发展其应用价值会越来越高。     

探讨近红外光谱技术在煤质分析中的应用

随着我国社会经济的发展,煤炭在人们的生活以及工作的方方面面都得到了广泛的应用,煤炭的使用情况取决于煤炭煤质的好坏。以往传统的检测方法具有很大的缺陷,例如,检测过程耗费的成本高、工作效率低下、检测之后的后续处理工作比较繁琐等,这就要求在煤质分析方面需要更新升级相应的检测技术,近红外光谱技术在煤质分析过程中的使用具有重要的意义。通过分析近红外光谱技术在煤质分析中应用的现状,以及近红外光谱技术运行的前景,旨在全面地提高近红外光谱技术在煤质分析中的全面应用,推进煤炭使用的效率,全面提高人们的生活水平。     

近红外光谱分析技术及其应用

对近红外分析技术的研究和应用进行了综述,包括近红外分析技术的概述、分类并分析其特点,重点介绍了近红外光谱分析技术在石化、煤炭、药物分析、食品、茶叶和烟草等领域的应用.     

近红外光谱分析技术在药品快速检测中的进展

近红外光谱技术为原位分析技术的一项重要内容,近些年来此项技术得到了快速的发展,采用校正模型建立的方式针对目标样品开展定量分析工作,可以实现对目标样品的无损检测,为当前阶段具有较强环保性的分析技术.在相关化学领域中,近红外光谱分析技术的出现实现了分析技术的改革,与传统的分析技术比较,近红外光谱技术可以在非常短的时间内,只...     

近红外光谱分析技术在石油化工中的应用

介绍近红外光谱分析技术的工作原理、光谱的预处理方法、定量分析方法、定性分析方法,综述了近红外光谱分析技术在石油化工领域中的应用现状,并对目前近红外光谱分析技术的发展方向作了简单的评论。     

一种中药大黄乙醇提取过程质量控制方法

本发明提供一种中药大黄乙醇提取过程质量控制方法,其特征在于包括如下步骤:步骤1、测定合格大黄乙醇提取液的比重及大黄素含量,并采集近红外光谱;步骤2、采用化学计量学软件分别建立大黄乙醇提取液近红外光谱     

采用Raman光谱研究硅烷接枝LLDPE的结晶结构

采用傅里叶变换红外光谱(FTIR)和Raman光谱表征了硅烷接枝线型低密度聚乙烯(LLDPE)的结晶结构。用FTIR和Raman光谱上硅烷特征峰与LLDPE亚甲基峰的强度比,可相对比较硅烷接枝LLDPE的接枝率,随着硅烷用量的增加,由FTIR计算的吸光比从0.96增至2.62,由Raman光谱计算的强度比从11.53增至14．00,两者的变化趋势相同。Raman光谱分析还表明,随着硅烷用量的增加,硅烷接枝聚乙烯的结晶相质量分数由57．58％降至46．99％,非晶相质量分数由11．58％升至16．52％,中间相质量分数从30．84％升至36．48％。     

In-line monitoring of the conversion in photopolymerized acrylate coatings on polymer foils using NIR spectroscopy

Near-infrared (NIR) reflection spectroscopy was used to monitor the conversion of double bonds in acrylate coatings after irradiation with UV light or electron beams. Quantitative analysis of the spectroscopic data was performed either with a chemometric method on the basis of the PLS algorithm or according to the Beer-Lambert law. FTIR spectroscopy was used for calibration. In-line monitoring of the conversion in pilot-scale was carried out on clear and pigmented coatings, which were applied to polymer foils or paper by roll coating. Useful data were obtained from layers with a thickness from 4 g/m² upwards and at line speeds of at least up to 120 m/min. It was shown that any change of the irradiation dose or other parameters such as inertization leads to an immediate response in the conversion record. Similar investigations were also performed on layers of UV-curable adhesives on the basis of acrylic hot-melts.     

Monitoring and control of styrene solution polymerization using NIR spectroscopy

Tailored polymer resins are frequently required for a given application. The lack of instruments for in‐line monitoring of polymer quality has long been recognized as an important problem in polymerization reactor control. Using the styrene solution polymerization system as an example, we present the use of near‐infrared (NIR) spectroscopy as an alternative tool for in‐line and in situ monitoring and control of monomer conversion and average molecular weight of polymer resins. By using a Kalman filter state estimator and an accurate first‐principle model, the control loop could be successfully closed to track desired monomer values and average molecular weights. Two process control strategies, one based on the optimal control theory and the other on model predictive control, were implemented both theoretically and experimentally. The experimental results showed that it is feasible to use NIR spectroscopy for the simultaneous control of monomer conversion and polymer average molecular weight. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1273–1289, 2003     

近红外光谱技术在含能材料成分分析中的建模研究

近红外光谱法在对含能材料成分的分析中采用不同波数以及不同区间的变量，并用偏最小二乘法建立数学模型。建模结果说明模型精度较高，缩减后的自变量矩阵X中提取的主成分对原因变量有着更好的解释能力，并提高了计算速度。     

Investigation of the phase separation of PNIPAM using infrared spectroscopy together with multivariate data analysis

The use of vibrational spectroscopy to investigate complex structural changes in polymers yields chemically rich data, but interpretation can be challenging and subtle but meaningful spectral changes may be missed through visual inspection alone. Multivariate analysis is an efficient approach to gain an oversight of small but systematic spectral differences anywhere within the spectra, providing further insight into structural changes and associated transformation mechanisms. In this study, the novel analytical approach of infrared spectroscopy combined with principal component analysis and Gaussian peak fitting was used to investigate the structural changes in aqueous solutions of a polymer, using poly(N-isopropyl acrylamide) (PNIPAM) in the atactic form and with controlled tacticity as a model system. Subtle spectral changes associated with the dehydration and phase separation upon heating included peak shifts, an area ratio change of the amide I band to the amide II band and formation of a new peak in the amide I band were efficiently detected. Dehydration and phase separation of PNIPAM occurred in two temperature ranges, one for the atactic and one for isotactic rich part, both involving a complex re-organization of the hydrogen bonds and change of the hydration layer. The changes agreed with existing results from other techniques, and new insights were gained into the effect of controlled tacticity on phase transformation behaviour. The study demonstrates that infrared spectroscopy combined with the multivariate analytical method principal component analysis and Gaussian peak fitting is an efficient approach to probing structural change in polymers during heating. The simplicity of the presented approach could find excellent use in analysing and understanding the molecular environment of a range of stimuli-responsive polymers, for instance block or grafted types of polymers, as well as those with controlled tacticity.     

Gasoline classification by source and type based on near infrared (NIR) spectroscopy data

In this paper, we have tried to classify 382 samples of gasoline and gasoline fractions by source (refinery or process) and type. Three sets of near infrared (NIR) spectra (450, 415, and 345 spectra) were used for classification of gasolines into 3 or 6 classes. We have compared the abilities of three different classification methods: linear discriminant analysis (LDA), soft independent modeling of class analogy (SIMCA), and multilayer perceptron (MLP) - to build effective and robust classification model. In all cases NIR spectroscopy was found to be effective for gasoline classification purposes. MLP technique was found to be the most effective method of classification model building.     

Discriminant analysis of vegetable oils by near-infrared reflectance spectroscopy

Discriminant analysis of four vegetable oil types (cotton-seed, peanut, soybean and canola) was performed by near-infrared reflectance spectroscopy. The objective of this study was to provide an alternate method to differentiate vegetable oil types and to classify unknown oil samples. Second derivative spectra of the vegetable oils were subjected to discriminate analysis with Mahalanobis distances principles. A four-wavelength (1704, 1802, 1816 and 2110 nm) equation was derived, which produced a sum of inverse squared distance of 0.0548. Although all four groups were successfully separated with a chi square of 18.9, the soybean oil group is more dispersed in space than the other three groups. Iodine values of the soybean oil samples suggest that this group may have a wide range of hydrogenation states. Discriminant analysis can be successfully used to differentiate vegetable oil types and possibly could also be used to differentiate degree of hydrogenation and oxidative states of oils.     

SIBR微观结构的红外光谱定量分析

采用聚苯乙烯、聚丁二烯和聚异戊二烯标准样品复配,建立了利用红外光谱工作曲线来测定苯乙烯-异戊二烯-丁二烯橡胶(SIBR)中苯乙烯、丁二烯反式-1,4结构、丁二烯顺式-1,4结构、丁二烯-1,2结构、异戊二烯-1,2结构、异戊二烯3,4-结构和异戊二烯-1,4结构等7种微观结构的定量分析方法,解决了使用红外光谱联立解方程组法来测定SIBR多种微观结构含量的困难。该方法方便、准确、可靠,也适用于嵌段共聚物SIBS的微观结构测定。     

Some aspects of the analysis of coal by X-ray fluorescence spectroscopy

Bituminous coal samples from 84 distinct sources were analysed by conventional British Standards (BS) methods for phosphorus, sulphur, chlorine, ash and the ash-forming elements (calcium, silicon, aluminium, iron, sodium, magnesium, potassium, titanium and manganese). In most cases four determinations were made per element per source. Samples were crushed to ?212 μm (72 BS mesh) and pressed into aluminium cups at 20 t in^?2 (309 MPa) without binder or backing. Two pellets from each sample were analysed by wave-length dispersive X-ray fluorescence techniques, using a spectrometer equipped with a rhodium rube; the X-ray count took 60 s. The X-ray results were calibrated against the conventional results using multiple regression. The accuracy obtained was comparable with routine ‘wet chemical’ techniques. The X-ray technique is suitable for the routine determination of large numbers of samples.