GP Algorithm-Based Fourier Transform Infrared Spectrum Trend Term Removal Model

Trend term removal is a key step in Fourier transform infrared spectroscopy(FTIR)data pre-processing.The most commonly used least squares(LS)method,although satisfying the real-time requirement,has many problems such as highly correlated initial values of the expression parameters,the need to pre-estimate the trend term shape,and poor fitting accuracy at low signal-to-noise ratios.In order to achieve real-time and robust trend term removal,a new trend term removal method using genetic programming(GP)in symbolic regression is constructed in this paper,and the FTIR simulation interference results and experimental measurement data for common volatile organic compounds(VOCs)gases are analyzed.The results show that the genetic programming algorithm can both reduce the initial value requirement and greatly improve the trend term accuracy by 20%-30% in three evaluation indicators,which is suitable for gas FTIR detection in complex scenarios.

Detection of Broad Bean Diseases by Fourier Transform Infrared Spectroscopy Combined with Curve Fitting

Fourier transform infrared （FTIR） spectroscopy was used to study diseased leaves in broad bean. Results showed that the infrared spectra of different broad bean diseased leaves were similar, which were mainly made up of the vibrational absorption bands of protein,lipid and polysaccharide.There were minor differences in-cluding the spectral peak position, peak shape and the absorption intensity in the range of 1 800-1 300 cm-1. There were obvious differences among their second derivative spectra in the range of 1 800-1 300 cm-1. After the procedure of the Fourier self-deconvolution and curve fitting of health bean leaves and broad bean diseased leaves in the range of 1 700-1 500 cm-1, three sub-peaks were obtained at 1 550 cm-1 （protein amide Ⅱ band）, 1 605 cm-1 （lignin） and 1 650 cm-1 （protein amide I band）.The ratios of relative areas of the bands of amide Ⅱ, lignin, and amide I were 38.86%, 28.68% and 32.47% in the spectra of healthy leaves, respec-tively. It was distinguished from the diseased leaves （chocolate spot leaf： 15.42%, 42.98% and 41.61%, ring spot leaf：32.39%, 35.63% and 31.98%, rust leaf： 13.97%, 46.40% and 39.65%, yel owing leaf curl disease leaf： 24.01%,36.55% and 39.44%）. For sub-peak area ratios （A1 563/A1 605, A1 650/A1 605 and A1 563/A1 654）, those of four kinds of diseased leaves were smal er than that of healthy leaves, and there were also differences among four kinds of diseased leaves. The results proved that FTIR combining with curve fitting might be a potential y useful tool for detecting different kinds of broad bean diseases.

Retrieval algorithm of quantitative analysis of passive Fourier transform infrared (FTRD) remote sensing measurements of chemical gas cloud from measuring the transmissivity by passive remote Fourier transform infrared

Passive Fourier transform infrared （FTIR） remote sensing measurement of chemical gas cloud is a vital technology. It takes an important part in many fields for the detection of released gases. The principle of concentration measurement is based on the Beer-Lambert law. Unlike the active measurement, for the passive remote sensing, in most cases, the difference between the temperature of the gas cloud and the brightness temperature of the background is usually a few kelvins. The gas cloud emission is almost equal to the background emission, thereby the emission of the gas cloud cannot be ignored. The concentration retrieval algorithm is quite different from the active measurement. In this paper, the concentration retrieval algorithm for the passive FTIR remote measurement of gas cloud is presented in detail, which involves radiative transfer model, radiometric calibration, absorption coefficient calculation, et al. The background spectrum has a broad feature, which is a slowly varying function of frequency. In this paper, the background spectrum is fitted with a polynomial by using the Levenberg-Marquardt method which is a kind of nonlinear least squares fitting algorithm. No background spectra are required. Thus, this method allows mobile, real-time and fast measurements of gas clouds.

The role of fluid polarity in the swelling of sodium-montmorillonite clay:A molecular dynamics and Fourier transform infrared spectroscopy study

Swelling clays are found extensively in various parts of the world, and sodium-montmorillonite(NaMMT) is the main constituent of an expansive clay mineral. In this work, the swelling behavior of NaMMT clay with a wide range of organic fluids, high polar through low polar fluids, is studied using a combination of Fourier transform infrared(FTIR) technique and molecular dynamics(MD) simulations.The construction of the representative clayefluid models is carried out, and the nature of nonbonded interactions between clay and fluids is studied using MD. Our FTIR and MD simulations results suggest the significant nonbonded interactions between Na-MMT clay and polar fluids, such as formamide and water. The nonbonded interactions of Na-MMT with methanol and acetone are significantly less than those in Na-MMT with polar fluids. The interactions of the fluids with various entities of the clay such as Sie O, Fee OH, Mge OH, and Ale OH captured via the spectroscopy experiments and modeling provide a finer understanding of the interactions and their contributions to swelling. The MD simulations are able to capture the band shifts observed in the spectra obtained in the spectroscopy experiments. This work also captures the conformations of interlayer sodium ions with formamide, water, methanol, and acetone during swelling. These nonbonded interactions provide insight into the molecular mechanism that the polarity of fluids plays an important role in the initiation of interlayer swelling, alteration in the orientations, and evolution of microstructure of swelling clays at the molecular scale.

Quantitative Analysis of Lignocellulosic Components of Non-Treated and Steam Exploded Barley, Canola, Oat and Wheat Straw Using Fourier Transform Infrared Spectroscopy

Rapid and cost effective quantification of lignocellulosic components （cellulose, hemicelluloses and lignin） of agricultural biomass （barley, canola, oat and wheat） is essential to determine the effect of various pre-treatments （such as steam explosion） on biomass used as feedstock for the biofuel industry. Fourier Transformed Infrared （FTIR） spectroscopy was considered as an option to achieve this objective. Regression equations having R2 values of 0.89, 0.99 and 0.98 were developed to predict the cellulose, hemicelluloses and lignin compounds of biomass, respectively. The average absolute difference in predicted and measured cellulose, hemicellulose and lignin in agricultural biomass was 7.5%, 2.5%, and 3.8%, respectively.

Identification of Plant-Pathogenic Fungi Using Fourier Transform Infrared Spectroscopy Combined with Chemometric Analyses

Identification of plant-pathogenic fungi is time-consuming due to cultivation and microscopic examination and can be influenced by the interpretation of the micro-morphological characters observed.The present investigation aimed to create a simple but sophisticated method for the identification of plant-pathogenic fungi by Fourier transform infrared(FTIR)spectroscopy.In this study,FTIR-attenuated total reflectance(ATR)spectroscopy was used in combination with chemometric analysis for identification of important pathogenic fungi of horticultural plants.Mixtures of mycelia and spores from 27fungal strains belonging to nine different families were collected from liquid PD or solid PDA media cultures and subjected to FTIR-ATR spectroscopy measurements.The FTIR-ATR spectra ranging from 4 000to 400cm-1 were obtained.To classify the FTIRATR spectra,cluster analysis was compared with canonical vitiate analysis(CVA)in the spectral regions of3 050~2 800and 1 800~900cm-1.Results showed that the identification accuracies achieved 97.53%and99.18%for the cluster analysis and CVA analysis,respectively,demonstrating the high potential of this technique for fungal strain identification.

Rapid Method for the Determination of Total Monosaccharide in <i>Enterobacter cloacae</i>Strains Using Fourier Transform Infrared Spectroscopy

Fourier Transform Infrared Spectroscopy (FTIR) was used to quantify total monosaccharide content in the bacterium Enterobacter cloacae and several of its biofilm mutants. Bacterial biofilm samples were grown on trypticase soy agar, and 30 μL aliquots of aqueous sample bacterial plus biofilm were deposited into the center of barium fluoride crystals and dried at 50°C for 1-hour before being scanned by FTIR. The total amounts of monosaccharides were estimated using the absorbance of the mono-saccharide peak, 1192 - 958 cm–1, and normalized using the amide II peak, 1585 - 1483 cm–1. This method provided a linear correlation between the absorbance of the monosaccharide peak and concentration of monosaccharide in standard monosaccharides, fructose, glucose, mannose, and rhamnose, over a concentration range of 0.5 - 2.0 mg/mL.

Fourier Transform Infrared Spectroscopic Study of Sodium Phosphate Solids and Solutions

Solids and solutions of sodium phosphates with various chain lengths have been studied by using the techniques of diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and attenuated total reflection-Fourier transform infrared (ATR-ETIR) spectroscopy, respectively. A systematic study of the infrared spectra of the solid sodium phosphates has been conducted on the basis of the information available it? the literatures to establish the assignments of the infrared vibrations of the different groups in the phosphate molecules. The infrared spectra of the solutions of sodium phosphates have been analyzed according to the infrared study on the relevant solids, in conjunction with the study of the phosphate species distribution in solution on the basis of the acid-base reaction equilibria. The results obtained have revealed the correlations between the infrared absorption spectra and the structure of the different P-O groups in different kinds of phosphates and are useful in the analysis of phosphate solids and solutions widely used in the various operations of mineral processing.

基于移动平台的便携式FTIR灾害现场气体检测技术

傅里叶红外光谱技术(FTIR)的引入极大地提升了气体的检测速度和准确性。然而在石油化工泄露和爆炸、森林火灾等突发危险现场,存在着人力无法现场检测的情况。为了应对这种场景,开发了基于移动平台的便携式FTIR灾害现场气体检测方法。通过将云服务器和树莓派的优势相结合实现远程操作移动平台,将搭载便携式FTIR光谱仪的移动平台远程操作驶入现场,并及时通过4G/5G模块传回现场位置数据、视频数据和光谱气体浓度数据。最后,在野外基地利用该平台进行了实测,对CO_(2)、CO、SO_(2)、C_(6)H_(6)等多种污染气体进行了检测,结果验证了该系统在野外工况下的可靠性。本工作为FTIR光谱仪或其他光谱类检测系统在移动平台上的集成应用提供了思路和解决方案。

Assessment of portable FTIR and Raman spectroscopy for the detection of 2,3-dimethyl-2,3-dinitrobutane(DMDNB)in plastic explosives

The Marplex Convention was established to prevent the manufacture of unmarked plastic explosives and stipulates that a volatile detection agent must be added at the time of manufacture.However,to-date,laboratory testing remains the internationally accepted practice for identifying and quantifying the taggants stipulated in the Convention.In this project,portable FTIR and Raman instruments were tested for their ability to detect 2,3-dimethyl-2,3-dinitrobutane(DMDNB),the chemical marker incorporated in plastic explosives that are manufactured within Australia.While both FTIR and Raman instruments detected solid DMDNB(98%purity),field analysis of plastic explosives at an Australian Defence establishment showed that both FTIR and Raman spectra were matched the relevant explosive(RDX or PETN),rather than the DMDNB taggant.For all three plastic explosives tested,the concentration of DMDNB was measured by SPME-GC-MS to be between 1.8 and 2%,greater than the minimum 1%concentration stipulated by the Marplex Convention.Additional testing with a plastic explosive analogue confirmed that the minor absorption peaks that would characterize low concentrations of DMDNB were masked by absorption bands from other compounds within the solid.Thus,while both FTIR and Raman spectroscopy are suitable for detection of plastic explosives,neither rely on the presence of DMDNB for detection.It is likely that similar results would be found for other taggants stipulated by the Marplex Convention,given they are also present in concentrations less than 1%.

当归痛风方对小鼠高尿酸血症肾病的FTIR研究

傅里叶变换红外光谱(FTIR)是鉴别物质和分析物质结构的有效手段,可对样品进行定性和定量分析,广泛应用于医药化工等众多领域。FTIR作为一种操作简便、实用、准确率高和费用低的鉴别方法,如今已经普遍应用于各种药品检验中,而有关其应用于药理研究中还非常少,目前仅有采用红外光谱分析法对各种肿瘤组织进行研究的报道。高尿酸血症肾病是人体血尿酸升高后,过高的尿酸负荷超过肾脏的清除能力,尿酸结晶沉积于集合管、肾盂和尿道等。采用FTIR技术评价高尿酸血症肾病模型,并评价药物的药效,具有一定的可行性。该实验为探讨FTIR评价高尿酸血症肾病模型和当归痛风方疗效的科学性,将60只KM小鼠随机分为6组,正常对照组、模型组、阳性对照组和当归痛风方低、中、高组,采用氧嗪酸钾复制高尿酸血症肾病模型,灌胃当归痛风方,检测血清UA、尿液UA、血清CRE、尿液CRE、血清IL-1β和肾脏IL-1β、肾脏FTIR谱图等,并观察肾脏的病理变化。结果表明模型组各项指标与正常组比较有统计学意义(p<0.05),当归痛风方高剂量组的血清UA、血清CRE、血清IL-1β和肾脏IL-1β等与模型组比较且有统计学意义(p<0.05)。当归痛风方高剂量组肾脏的病理变化有所改善,无炎性细胞浸润,管腔内无管型,说明对肾损伤具有保护作用。各组FTIR谱有明显的差异,模型组的强度均低于正常组,阳性对照组和当归痛风方高剂量组谱接近正常组,进一步说明当归痛风方对肾损伤具有保护作用。研究表明FTIR可以作为一种简便快捷灵活经济的评价动物模型及药物疗效的方法之一,也为高尿酸血症肾病模型及有效药物的筛选提供了一个有意义的技术手段。该实验拓展了FTIR检测方法的使用范围。

模块化FTIR测定FCV用氢气痕量杂质

设计构建了用于质子交换膜燃料电池汽车(FCV)氢气痕量杂质的模块化FTIR分析表征平台,开发了适用于氢气痕量杂质的分析方法,无需处理一次进样,能够同时快速测定HCOOH、CO、CO_(2)、NH_(3)、H_(2)O、CH_(4)、C_(2)H_(4)、C_(2)H_(6)、HCHO等多种痕量级别杂质。考察了各含氢杂质分析的影响因素,精选了杂质物种定性区域,优化了定量方法,提出了实用性强的定量检出限,在降低了背景气和空白气纯度的要求也能确保限值浓度准确测定。九种杂质的计算方法检出限达到ASTM D7653-18参考值,其定量限也均低于ISO 14687:2019相应的限值,定量线性范围约2个数量级,相关系数均大于0.999,准确度和精密度均不高于10%,通过ISO 21087:2019规定的方法适用性验证规则,满足ISO 14687:19相应的质控标准。根据不同场景需求,样品模块、气体净化控制模块、配气模块、红外分析模块和尾气处理模块可以有机结合并具有良好的实用性和扩展性,尾气处理后氢气浓度可降至100μmol·mol^(-1)以下排放,满足安全绿色环保的要求。与实验室其他参考方法测定值有较好的一致性,并已在FCV氢气工业生产样品质量检测中得到应用,它将从实验室离线方法逐步发展成为适用于工业不同场景的在线方法,这对燃料级氢气品质体系的建立、纯化技术的推广应用及燃料电池催化剂新材料开发均具有意义。

Comparative Study on the Infrared Spectra of Straight Guard Hairs of Leopard Cat and Golden Cat

[Objective] The paper was to compare the infrared spectra of straight guard hairs of leopard cat and golden cat. [Method] The straight guard hairs of leopard cat and golden cat were detected and analyzed by FTIR （Fourier Transform Infrared Spectroscopy）. [Result] There was significant interspecific difference in the infrared spectra and second derivative spectra for the middle part of guard hair. An evident M-shaped bimodal absorption peak appeared in golden cat at 648 and 654 cm-1, respectively, while did not appear in leopard cat. The second derivative spec-tra of golden cat at wave numbers from 709 to 763 cm -1 were mainly unimodal peaks with strong peak intensity, while that of leopard cat mainly was M-shaped bi-modal absorption peak with weak peak intensity. It indicated that there was obvious difference in the structure of protein side chain in guard hairs of these two animals. [Conclusion] The FTIR analysis showed great application foreground in the study of animal hairs for interspecific identification.

Thermal,infrared spectroscopy and molecular modeling characterization of bone:An insight in the apatite-collagen type I interaction

An insight into the interaction of collagen type I with apatite in bone tissue was performed by using differential scanning calorimetry, Fourier transform infrared spectroscopy, and molecular modeling. Scanning electron microscopy shows that bone organic content incinerate gradually through the different temperatures studied. We suggest that the amide regions of the type I collagen molecule (mainly C=O groups of the peptide bonds) will be important in the control of the interactions with the apatite from bone. The amide I infrared bands of the collagen type I change when interacting to apatite, what might confirm our assumption. Bone tissue results in a loss of thermal stability compared to the collagen studied apart, as a consequence of the degradation and further combustion of the collagen in contact with the apatite microcrystals in bone. The thermal behavior of bone is very distinctive. Its main typical combustion temperature is at 360°C with a shoulder at 550°C compared to the thermal behavior of collagen, with the mean combustion peak at ca. 500°C. Our studies with molecular mechanics (MM+ force field) showed different interaction energies of the collagen-like molecule and different models of the apatite crystal planes. We used models of the apatite (100) and (001) planes;additional two planes (001) were explored with phosphate-rich and calcium-rich faces;an energetic preference was found in the latter case. We preliminary conclude that the peptide bond of collagen type I is modified when the molecule interacts with the apatite, producing a decrease in the main peak from ca. 500°C in collagen, up to 350°C in bone. The combustion might be related to collagen type I, as the ΔH energies present only small variations between mineralized and non-mineralized samples. The data obtained here give a molecular perspective into the structural properties of bone and the change in collagen properties caused by the interaction with the apatite. Our study can be useful to understand the biological synthesis of minerals as well as the organic-inorganic interaction and the synthesis of apatite implant materials.

云南普阳煤矿新近系褐煤中稀土元素的赋存状态

目前对于褐煤中稀土元素(REY)赋存状态的研究还存在较多疑问,主要体现在两个方面:一是褐煤中REY究竟主要赋存于有机质中还是矿物质中?二是褐煤含有较多容易受到酸溶干扰的含氧官能团,在逐级化学提取实验过程中,高比例HCl提取相中的REY究竟来自于碳酸盐、磷酸盐、单硫化物等矿物还是来自于有机质?着眼于此,本文在逐级化学提取这一常规元素赋存状态研究方法的基础上,结合密度分离实验、红外光谱(FTIR)等手段,对普阳煤矿新近系褐煤中REY的赋存状态进行了系统研究。研究结果表明,普阳煤矿M2和M3煤层为极低—中灰、中高—高挥发分、中硫分褐煤,其组成矿物主要为石英、方解石、高岭石、黄铁矿。M2和M3煤层中常量元素以Al和Si为主,其REY配分模式主要为L型和N型,其中M2煤层中REY轻度富集。逐级化学提取实验结果显示M2和M3煤层中的REY主要被HCl浸取,其次被HNO3浸取,同时还有部分REY保留在残渣中,HF对煤中REY的提取率很低(一般<10%)。密度分离实验结果表明REY主要赋存于低密度组分中。红外光谱分析结果显示煤样品经HCl处理后,酚羟基、羟基等含氧官能团增多,可能是经HCl浸取后样品中与酚羟基、羟基点位结合的REY被浸出迁移所致。综合来看,普阳煤矿M2和M3煤层中的REY主要赋存于有机质中,少量赋存于硅酸盐矿物中,碳酸盐、磷酸盐、单硫化物和双硫化物也可能是部分REY的赋存载体。逐级化学提取实验过程中HCl所提取的异常高比例的REY可能主要来自于有机质。

不同溶剂预处理煤在ScCO_(2)作用下的谱学差异及其机制

为了探究溶剂预处理后超临界二氧化碳(ScCO_(2))对煤化学结构的影响,以长治霍尔辛赫贫煤为研究对象,分别用四氢呋喃(THF)、盐酸(HCI)和氢氟酸(HF)对煤样进行预处理,采用傅里叶红外光谱(FTIR)、固体核磁共振(^(13)C-NMR)和X射线衍射(XRD)测试,探讨了ScCO_(2)对预处理煤的化学组成和结构的影响机理。研究表明:①FITR分峰拟合谱图实验曲线基本一致,而各官能团吸收峰位置及峰强度仍出现一定的偏差,酸(HCI、HF)预处理后部分波段脂肪族峰位消失。两类酸预处理顺序不同,对煤中含氧官能团、脂肪结构及芳烃结构作用效果也不相同。HF-HCI处理后芳烃C=C结构和含氧官能团峰强度均增强,而HCI-HF处理后芳烃C=C结构强度减弱,含氧官能团结构峰强度变化不明显。THF预处理后煤样芳烃C=C结构峰强度增强,含氧官能团结构峰强度降低。总体芳烃C=C结构峰强度远大于脂肪族结构和含氧官能团结构的峰强度。②^(13)C-NMR谱中主要官能团谱峰的化学位移出现了一定程度的偏移,芳香碳f_(a)^(B)化学位移向增大的方向偏移。大分子结构参数中,芳香碳含量远大于脂肪碳含量,说明煤大分子结构中芳香碳占主要组成部分。③XRD谱中002峰与101峰衍射强度明显增大,芳香微晶层网面间距d_(002)呈现升高趋势,说明THF、酸(HF、HCI)处理和ScCO_(2)对煤大分子结构产生了一定程度的改造作用,使煤的大分子网络结构变得疏松,进而使微晶结构参数d_(002)整体增大。研究认为,溶剂作用后煤的谱学特征变化不仅与溶剂性质有关,还与无机酸处理顺序有关,由此使得官能团组成和大分子结构不同程度改变,进而影响ScCO_(2)对预处理煤的萃取效果。

银耳多糖对麦醇溶蛋白纳米体系的影响及复合物的特性研究

该研究是以提高麦醇溶蛋白(gliadin,Gli)纳米颗粒(gliadin nanoparticles,GNPs)稳定性为目标,利用银耳多糖(Tremella fuciformis polysaccharides,TFPs)的乳化性能,探究TFPs添加量对GNPs稳定性的影响。采用反溶剂法制备银耳多糖和麦醇溶蛋白复合载体颗粒(gliadin-Tremella fuciformis polysaccharides composite nanoparticles,G/T NPs),并利用纳米粒度仪、傅里叶变换红外光谱仪、热场发射扫描电镜对G/T NPs的粒径和电位、相互作用、微观结构进行分析。结果表明,TFPs和Gli之间通过静电作用力和氢键作用力相结合,形成GNPs在内、TFPs外层附着的复合颗粒;TFPs的添加能够有效提高GNPs体系的稳定性,减少颗粒之间的聚集,制得的G/T_(4∶1)NPs的平均粒径、多分散指数(polydispersion index,PDI)、ζ-电位分别为(198.5±2.6)nm、0.269±0.005、(36.7±0.6)mV,且具有pH响应性。该研究为后续构建疏水营养成分的包埋和运载体系奠定了基础。

应用衰减全反射红外光谱无损鉴别中国传统手工纸的方法研究

纤维种类鉴别是古代纸张保护的重要基础工作。探究中国传统手工纸的无损纤维鉴别的方法对中国古籍、档案及纸质文物的研究和保护具有重要意义。该研究应用衰减全反射傅里叶变换红外光谱(ATRFTIR)对已知纤维成分的17类64种中国传统手工纸标准样品进行了无损分析,参考纤维素和木质素的红外峰位及部分纸样的X射线衍射(XRD)分析结果确认纸样中的所有红外谱峰归属;并采用分波段比较分析的方法对相似度极高的谱图进行比对分析,分别总结各类纸张在4000~1800、1800~1500、1500~1200和1200~600cm^(-1)四个波段的谱图特征;同时对4cm^(-1)精度的谱图进行二阶导数处理,分别总结各类纸张在1500~1200和1200~900cm^(-1)两个波段的二阶导数谱图特征;最后通过红外结晶指数及其他峰高和峰面积比值计算结果实现对纸类更细致的区分。应用上述方法对16个盲测样品进行了有效性测试,红外分析结果与显微纤维鉴别结果一致,初步证明了该方法在中国传统手工纸无损纤维鉴别上的可行性和有效性。实验结果表明,应用ATR-FTIR无损分析法可对麻、桑构皮、檀皮、瑞香皮和竹几大类原料的传统手工纸纤维类型作出快速而准确的鉴别,对于混料的宣纸也同样适用;但对于显微分析也难以鉴别的亲缘关系较近的植物原料如桑、构皮之间的精细鉴别仍有一定局限性。

用FTIR光谱仪测量排气系统中红外光谱辐射强度的方法

通过理论分析及实验研究讨论了傅立叶变换红外(FTIR)光谱仪测量排气系统中红外光谱辐射强度过程中误差产生的原因,设计了一套简易有效的测量方法.用此方法测量了黑体和热喷流的光谱辐射强度.结果表明:该测量方法能够有效地获得排气系统的中红外光谱辐射强度,具有工程实用价值.

铬诱导植物根细胞壁化学成分变化的FTIR表征

随着制革、电镀等行业的发展,铬污染已成为严重的环境问题而受到人们的关注。铬在植物体内主要积累于根部,植物根细胞壁化学变化与金属元素在植物体内的蓄积行为有密切关系。与其他方法比较,应用OMNI采样器-FTIR直接测定法表征细胞化学成分变化具有简便、快速和准确的优点。文章用FTIR对凤眼莲(Eichhornia crassipes)和空心莲子草(Alternanthera philoxeroides)根细胞壁进行了测定、分析和指认,并利用半定量分析方法研究了铬处理和对照处理下根细胞壁红外光谱的差异。结果表明,铬处理的凤眼莲和空心莲子草根细胞壁上的—OH向低频分别发生了20和6 cm-1的位移,同时凤眼莲的根细胞壁上—OH和自由羧基COO-等吸附位点数目较对照均有所增加,而空心莲子草则相反。说明这些基团与铬的结合密切相关,进一步解释了凤眼莲耐铬及其在根部积累铬的机理,说明FTIR在监测逆境诱导植物化学成分变化和环境绿色修复方面具有广泛的应用前景。