近年来我国近红外光谱分析技术的研究与应用进展

对我国近10年来近红外光谱分析技术的研究与应用进展作了较为详细的综述,包括近红外光谱仪器研制、化学计量学方法及软件开发和在各领域的实际应用.根据国际上近红外光谱分析技术的现状和国内实际情况,提出了今后我国近红外光谱分析技术的发展方向.     

BCEIA‘99金奖产品NIR—2000近红外光谱仪和化学计量学光谱分析软件

介绍了ＢＣＥＩＡ’９９金奖产品ＮＩＲ－２０００近红外光谱仪和化学计量学光谱分析软件及其成套技术的主要特点，以及近红外光谱快速分析技术将在我国分析领域中产生一次技术革命的作用     

油品仪器分析的现状和发展趋势

对近年来用于石油产品仪器分析方法的现状进行了评述,并探讨了发展趋势。色谱法和光谱法仍是油品分析应用最广泛的方法,近红外光谱正快速进入石化分析领域,而化学计量学是处理信息的有效工具。     

拉曼光谱成像技术新进展及其应用

拉曼光谱成像技术是拉曼光谱分析技术的新发展,借助于现代共焦显微拉曼光谱仪器以及新型信号探测装置,它把简单的单点分析方式拓展到对一定范围内样品进行综合分析,用图像的方式显示样品的化学成分空间分布、表面物理化学性质等更多信息。本文介绍拉曼光谱成像技术的基本原理和实验方法,并且特别介绍HORIBA Jobin Yvon公司的新型快速拉曼成像技术SWIFT和DuoScan,最后用实验实例说明这些技术的重要应用。     

利用近红外光谱分析技术在线检测油品物理性质

随着计算机、化学计量学和现代信息技术的发展．一种先进的信息提取技术——近红外光谱(NIR)过程分析技术已经成熟．通过建立相应模型，利用一套在线近红外光谱分析系统在线快速检测多种介质的物理性质和质量指标已成为现实。     

显微荧光光谱成像仪的研究与设计

将光谱分析技术快速、灵敏、准确等独特的优点,与光学成像技术的定位记录特点融合、构成光谱成像技术,可以提供分析试样中各种化学或生化成份的分布图像,因而可以获得定性、定量和定位综合、更丰富的分析信息。报导在商售落射荧光显微镜基础上,实现显微镜荧光光谱成像技术的理论基础、系统组成、设计技术关键等一系列研究工作,设计研制成了可在250~680nm波长范围内自动扫描的光纤激发显微荧光光谱成像仪样机,并获得了满意的实验结果。     

近红外化学成像的原理、仪器及应用

随着过程分析技术的发展,近红外化学成像技术逐渐兴起.近红外化学成像结合了传统的光学成像和近红外光谱学方法,具有两者的特点,可以同时获得被测物质的空间信息和光谱信息.本文介绍近红外化学成像技术的原理、目前的仪器和实际应用情况,并对近红外化学成像技术的发展方向进行了展望.     

近红外光谱技术在食品安全领域的最新应用与展望

近红外光谱技术是近20年来发展迅速的新型分析检测技术,具有准确、简便、快速和不破坏样品等诸多特点,可以方便地实现鉴别食品成分掺假、食品种类、追溯不同产品来源、检测农兽药残留等。近红外光谱技术所具有的无损检测这一突出优势,使其在食品安全领域有着广阔的前景。本文就近红外光谱技术的发展及其在食品领域方面的应用进行探讨,并对其今后在该领域的发展进行展望。     

基于近红外光谱的老陈醋不同品牌的鉴别分析

应用近红外透射光谱技术,结合化学计量学方法,开展老陈醋不同品牌的定性检测的研究,并对可行性加以分析.在800 nm到2500 nm内对老陈醋进行光谱采集,并通过主成分分析(PCA)和判别分析(DA)建立定性分析模型,对不同波长所建立模型的优劣加以分析.结果表明,在波长800~2500 nm的范围内建立的模型最为稳定,正确率为96.3%.近红外光谱技术可以快速地对陈醋的不同品牌作出分析     

干烟叶的显微近红外图像分析

采集干烟叶的显微近红外图像,并用主成分分析方法和相关光谱成像的方式对其进行图像分解,并且比较2种图像分解方法的特点。结果表明,对干烟叶样品的显微近红外图像采用主成分分析的方法提取其特征向量,并将第二主成分特征向量与淀粉的近红外光谱对比,特征向量与标准物质光谱的相关系数达到0.9779,表明第二主成分的特征向量主要源于淀粉,第二主成分得分值图像主要代表干烟叶中淀粉的分布;干烟叶的淀粉相关光谱成像图和第二主成分得分值图像的分布形状和趋势基本一致。     

Multiphoton microscopy in life sciences

Near infrared (NIR) multiphoton microscopy is becoming a novel optical tool of choice for fluorescence imaging with high spatial and temporal resolution, diagnostics, photochemistry and nanoprocessing within living cells and tissues. Three‐dimensional fluorescence imaging based on non‐resonant two‐photon or three‐photon fluorophor excitation requires light intensities in the range of MW cm^?2 to GW cm^?2, which can be derived by diffraction limited focusing of continuous wave and pulsed NIR laser radiation. NIR lasers can be employed as the excitation source for multifluorophor multiphoton excitation and hence multicolour imaging. In combination with fluorescence in situ hybridization (FISH), this novel approach can be used for multi‐gene detection (multiphoton multicolour FISH). Owing to the high NIR penetration depth, non‐invasive optical biopsies can be obtained from patients and ex vivo tissue by morphological and functional fluorescence imaging of endogenous fluorophores such as NAD(P)H, flavin, lipofuscin, porphyrins, collagen and elastin. Recent botanical applications of multiphoton microscopy include depth‐resolved imaging of pigments (chlorophyll) and green fluorescent proteins as well as non‐invasive fluorophore loading into single living plant cells. Non‐destructive fluorescence imaging with multiphoton microscopes is limited to an optical window. Above certain intensities, multiphoton laser microscopy leads to impaired cellular reproduction, formation of giant cells, oxidative stress and apoptosis‐like cell death. Major intracellular targets of photodamage in animal cells are mitochondria as well as the Golgi apparatus. The damage is most likely based on a two‐photon excitation process rather than a one‐photon or three‐photon event. Picosecond and femtosecond laser microscopes therefore provide approximately the same safe relative optical window for two‐photon vital cell studies. In labelled cells, additional phototoxic effects may occur via photodynamic action. This has been demonstrated for aminolevulinic acid‐induced protoporphyrin IX and other porphyrin sensitizers in cells. When the light intensity in NIR microscopes is increased to TW cm^?2 levels, highly localized optical breakdown and plasma formation do occur. These femtosecond NIR laser microscopes can also be used as novel ultraprecise nanosurgical tools with cut sizes between 100 nm and 300 nm. Using the versatile nanoscalpel, intracellular dissection of chromosomes within living cells can be performed without perturbing the outer cell membrane. Moreover, cells remain alive. Non‐invasive NIR laser surgery within a living cell or within an organelle is therefore possible.     

显微高光谱成像系统的设计

设计出一种基于棱镜 光栅 棱镜组合分光方式的显微高光谱成像实验系统.系统根据推帚式成像光谱仪的原理进行设计,采用棱镜 光栅 棱镜组合元件在后光学系统进行光谱分光,利用高精度载物台自动装置驱动样品进行推扫成像,选用PCI总线作为数据采集的微机接口.整个系统由显微镜、分光计、面阵CCD相机、载物台自动装置以及数据采集与控制模块等几部分组成.系统的光谱范围从400nm到800nm,120个波段,光谱分辨率优于5nm,空间分辨率大约1μm.该系统具有直视性、光谱分辨率高、结构紧凑、成本低等优点;不仅能够提供微小物体在可见光范围的单波段显微图像,而且能够获得图像中任一像素的光谱曲线,实现了光谱技术和显微成像技术的结合,成功的将成像光谱技术应用到显微领域,可广泛应用于临床医学、生物学、材料学、微电子学等学科领域.     

PLS定标法在近红外光谱分析仪中的应用研究

近红外光谱分析仪在农产品、水质监测和石油等许多领域有广泛的应用.这是一种在线实时分析仪器.光谱分析仪的定量分析有许多种方法.PLS(PartialLeast-Squares)法是在传统的多元线性回归的基础上发展起来的一种回归方法.文中针对40种烟草样品的红外光谱数据分别采用PLS回归法和MLR(Multiple Linear Regression)回归法进行分析.两种回归方法的结果与样品的化学位对比,表明PLS法是一种比较好的多变量定标方法,比较适合于实时在线定标分析.     

Developing a Vis/NIR spectroscopic system for fast and non-destructive pesticide residue monitoring in agricultural product

In this research, an optical system based on fibre optic Vis/NIR spectroscopy combined with chemometrics methods and software as a graphical user interface (GUI) was developed and presented for fast and non-destructive detection and determination of pesticide residues in agricultural products (a case study on diazinon in intact cucumbers). Vis/NIR spectra of cucumber samples without and with different concentrations of diazinon residue were analyzed at the range of 450–1000 nm. Partial least squares (PLS) regression models were developed based on chemical reference measurements and the spectral information of the samples after performing different pre-processing methods. Moreover, partial least squares-discriminant analysis (PLS-DA) models were developed based on different spectral pre-processing techniques to classify cucumbers with contents of diazinon below and above the maximum residue limits (MRL) as safe and unsafe samples, respectively. Finally, user-friendly software as a GUI was created based on the best PLS and PLS-DA models developed for prediction of diazinon contents in the samples and for classification of intact cucumbers by the absence/presence of diazinon residues, respectively. Evaluation of the system and software designed based on the best developed PLS and PLS-DA models indicated good performance for measuring and detection of diazinon residue in cucumbers. It was concluded that the designed system and software based on Vis/NIR spectroscopy combined with chemometrics methods can be utilized for fast and non-destructive safety control of intact cucumbers by the absence/presence of diazinon residues. It can also be generalized for detection of other pesticide residues in agricultural products if developing their appropriate models is feasible.     

近红外光谱法快速测定葛根中的五种成分

本文应用近红外光谱技术建立了快速检测葛根中有效成分的方法。研究了优化分析葛根总异黄酮、葛根素、大豆苷、淀粉和粗蛋白含量数学模型的各种条件,结果表明:建模样品集的化学值(又称真值)与近红外预测值的相关系数分别为:葛根总异黄酮R= 0.9752,葛根素R=0.9839,大豆苷R=0.9659,淀粉R=0.9628,粗蛋白R=0.9829;检验样品集的化学值与近红外预测值的相关系数分别为:0.9818,0.9752,0.9772,O.9737和0.9798。说明所建模型具有实际应用价值。     

The design and implementation of a high-fidelity Raman imaging microscope

We describe a Raman imaging microscope that produces high-fidelity, large format Raman images and Raman spectra from samples as small as 1 μm in size. Laser illumination is delivered to the object by means of an infinity corrected microscope objective, either by a galvanometer scanning system or a widefield fibre optic. Wavelength selection of Raman scattered emission is achieved by an acousto-optic tunable filter (AOTF), which maintains image fidelity and provides either continuous or random wavelength selection. The collimated AOTF output is imaged first by a tube lens and then by a projection lens onto a cooled silicon CCD array. Instrument features, including factors that determine the system's spatial and spectral resolution, and design considerations are discussed in detail. Images and spectra of test objects and samples that demonstrate the capability of this imaging spectrometer are presented. The potential of intrinsic chemical imaging is discussed in terms of its use in the analyses of a variety of chemical and biological samples.     

Comparison of hyperspectral classification methods for the analysis of cerium oxide nanoparticles in histological and aqueous samples

Hyperspectral imaging (HSI) and classification are established methods that are being applied in new ways to the analysis of nanoscale materials in a variety of matrices. Typically, enhanced darkfield microscopy (EDFM)‐based HSI data (also known as image datacubes) are collected in the wavelength range of 400–1000 nm for each pixel in a datacube. Utilising different spectral library (SL) creation methods, spectra from pixels in the datacube corresponding to known materials can be collected into reference spectral libraries (RSLs), which can be used to classify materials in datacubes of experimental samples using existing classification algorithms. In this study, EDFM‐HSI was used to visualise and analyse industrial cerium oxide (CeO₂; ceria) nanoparticles (NPs) in rat lung tissues and in aqueous suspension. Rats were exposed to ceria NPs via inhalation, mimicking potential real‐world occupational exposures. The lung tissues were histologically prepared: some tissues were stained with hematoxylin and eosin (H&E) and some were left unstained. The goal of this study was to determine how HSI and classification results for ceria NPs were influenced by (1) the use of different RSL creation and classification methods and (2) the application of those methods to samples in different matrices (stained tissue, unstained tissue, or aqueous solution). Three different RSL creation methods – particle filtering (PF), manual selection, and spectral hourglass wizard (SHW) – were utilised to create the RSLs of known materials in unstained and stained tissue, and aqueous suspensions, which were then used to classify the NPs in the different matrices. Two classification algorithms – spectral angle mapper (SAM) and spectral feature fitting (SFF) – were utilised to determine the presence or absence of ceria NPs in each sample. The results from the classification algorithms were compared to determine how each influenced the classification results for samples in different matrices. The results showed that sample matrix and sample preparation significantly influenced the NP classification thresholds in the complex matrices. Moreover, considerable differences were observed in the classification results when utilising each RSL creation and classification method for each type of sample. Results from this study illustrate the importance of appropriately selecting HSI algorithms based on specific material and matrix characteristics in order to obtain optimal classification results. As HSI is increasingly utilised for NP characterisation for clinical, environmental and health and safety applications, this investigation is important for further refining HSI protocols while ensuring appropriate data collection and analysis.     

Material analysis with cathodoluminescence standard spectra

There are several cases where x-ray analyses of material cannot yield the desired results (e.g., if materials of nearly identical chemical composition are considered.) Spectral cathodoluminescence (CL) investigations can be used to overcome these difficulties. For this purpose, CL standard spectra of different standard substances are presented here. The validity of these spectra is demonstrated by spectral analysis of a fireproof ceramic consisting of Al₂O₃ and of quartz and by an attempt to explain the origin of the CL properties of magmatic Zircon which is of significant importance in the field of geochronological investigations.     

Mapping chemical and bonding information using multivariate analysis of electron energy-loss spectrum images

Electron energy-loss spectroscopy (EELS) in the transmission electron microscope (TEM) is used to obtain high-resolution information on the composition and the type of chemical bonding of materials. Spectrum imaging, where a full EEL spectrum is acquired and stored at each pixel in the image, gives an exact correlation of spatial and spectral features. However, determining and extracting the important spectral components from the large amount of information contained in a spectrum image (SI) can be difficult. This paper demonstrates that principal component analysis of EEL SIs can be used to extract chemically relevant components. With weighted or two-way scaled principal component analysis, both compositional and bonding information can be extracted. Mapping of the chemical variations in a partially reduced titanium dioxide sample and the orientation-dependent bonding in boron nitride and carbon nanotubes are given as examples.     

DIC image reconstruction on large cell scans

The width of the emission spectrum of a common fluorophore allows only for a limited number of spectral distinct fluorescent markers in the visible spectrum, which is also the regime where CCD-cameras are used in microscopy. For imaging of cells or tissues, it is required to obtain an image from which the morphology of the whole cell can be extracted. This is usually achieved by differential interference contrast (DIC) microscopy. These images have a pseudo-3D appearance, easily interpreted by the human brain. In the age of high throughput and high content screening, manual image processing is not an option. Conventional algorithms for image processing often use threshold-based criteria to identify objects of interest. These algorithms fail for DIC images as they have a range from dim to bright with an intermediate intensity equal to the background, so as to produce no clear object boundary. In this article we compare different reconstruction methods for up to 100 MB-large DIC images and implement a new iterative reconstruction method based on the Hilbert Transform that enables identification of cell boundaries with standard threshold algorithms.