基于红外光谱的苹果叶病害的快速诊断

基于傅里叶变换红外光谱技术,利用光谱检索的方法对苹果叶病害进行病害类型的鉴别研究。测试了正常苹果叶片和4种病害叶片共75份样本的红外光谱,光谱显示,各类样品的红外光谱非常相似,主要由纤维素、木质素、蛋白质和脂类的吸收带组成。利用omnic8.5软件依次建立了由每类样品的平均红外光谱、一阶导数光谱和二阶导数光谱组成的光谱库Lib1、Lib2、Lib3。各样品红外光谱分别与光谱库Lib1进行专家检索和绝对微分差算法检索,专家检索的正确率为80%,绝对微分差检索的正确率为82.7%。各样品红外光谱的一阶导数光谱和二阶导数光谱分别与光谱库Lib2、Lib3在全谱范围进行绝对微分差检索,基于一阶导数光谱的检索正确率为93.3%,二阶导数光谱的检索正确率为82.7%。结果表明:基于一阶导数红外光谱的绝对微分差算法的检索更适合于苹果叶病害的鉴别。基于红外光谱技术的光谱检索的方法能较好地鉴别苹果叶病害,有望成为简便、快捷、低成本的植物病害的鉴别方法。     

基于中红外漫反射光谱的土壤重金属元素含量预测研究

研究了中红外漫反射光谱快速预测土壤重金属元素含量的可行性。以在南京江宁区和八卦洲采集的共161个土壤样品为例,利用偏最小二乘回归(PLSR)法对土壤中Ni,Cr,Cu,As,Zn,Pb,Hg和Cd等8种重金属元素数据进行了预测。通过对样品的中红外(MIR)漫反射光谱进行各种预处理,探讨了中红外光谱数据预处理对预测精度的影响,并比较了中红外光谱与可见光-近红外(VNIR)光谱对土壤重金属含量预测的精度。结果表明,依次经平滑、基线校正、多元散射校正预处理能显著提高中红外光谱数据的预测精度;经校正的中红外光谱对异地样品预测的均方根误差是可见光-近红外光谱的21%～73%,比VNIR波段更能准确预测异地样品中土壤重金属元素含量。研究表明,中红外漫反射光谱可以作为一种快速、非破坏方法预测土壤重金属元素含量,且比可见光-近红外精度高。     

彝药包谷七和见肿消的红外光谱

采用傅里叶变换红外光谱法测定彝药包谷七和见肿消的红外光谱图。分析比较了两种彝药在红外光谱图上的异同,结果表明,两种样品在红外光谱图上的吸收峰的峰形、吸收位置和强度均有差异,不同样品的特征吸收峰明显,通过分析红外光谱,为彝药的识别、鉴定和药理分析提供了一定的科学依据。     

基于FTIR的苔藓植物表征关系除趋势对应分析

苔藓植物是一类重要高等植物。但是,苔藓植物体型小,可供鉴别性状少。应用OMNI采样器-傅里叶变换红外光谱直接测定法鉴别植物样品具有简便、快速和准确的优点。应用傅里叶变换红外光谱直接测定法测定了苔藓植物26种30个样品的红外光谱,以波数-吸光度为指标来表征吸收峰,以红外光谱图为对象,应用除趋势对应分析(Detrended Correspondence Analysis, DCA)比较了30个样品在红外光谱图上的差异程度。结果发现,基于傅里叶变换红外光谱的除趋势对应分析反映出苔藓植物红外光谱的差异与它们分类关系有较好的对应性。因此,应用傅里叶变换红外光谱直接测定法能够鉴别药用苔藓植物。     

癌症患者及正常人指甲的红外光谱研究

利用傅里叶红外光谱研究了20例正常人和3例左上颌窦癌、前列腺癌、胆管癌三种癌患者手指甲的红外光谱，结果表明：癌症患者指甲样品与正常人指甲样品的红外光谱在峰形、峰强度、峰频率等方面均存在明显差异。     

溴化钾质量对红外光谱测试结果的影响

溴化钾(KBr)在中红外区段没有吸收峰,所以常作为红外光谱测试样品的载体。如果溴化钾试剂中混有杂质,则杂质产生的吸收峰会对样品测试的红外光谱形成干扰和影响。对国内外多家厂商的溴化钾试剂分别进行了红外光谱测试,就溴化钾试剂质量对红外光谱测试的影响进行了分析和论述。分析表明,红外光谱实验所选用的溴化钾纯度至少应当在99%以上。     

红外光谱结合光谱检索对石斛品种的鉴别研究

用傅里叶变换红外光谱技术结合光谱检索的方法对石斛茎进行品种鉴别研究。测试了23个品种,165株石斛茎样品的红外光谱,光谱显示,各样品的红外光谱非常相似,石斛茎中的主要成分是纤维素等多糖物质。利用光谱软件Omnic8.0建立了三个光谱数据库Lib01、Lib02和Lib03,Lib01由每个品种前4株样品的平均光谱组成,Lib02由平均光谱的一阶导数光谱组成,Lib03由平均光谱的二阶导数光谱组成。各样品光谱分别与Lib01进行指定在1 800～500 cm-1光谱范围的相关性、平方差和平方微分差检索,相关性检索的正确率达到92.7%,平方差检索的正确率达到74.5%,平方微分差检索的正确率达到92.7%。各样品光谱的一阶导数光谱和二阶导数光谱分别与Lib02和Lib03进行指定在1 800～500 cm-1光谱范围的平方微分差检索,一阶导数光谱的检索正确率达到93.9%,二阶导数光谱的检索正确率达到90.3%。结果表明,平方微分差算法的一阶导数红外光谱检索更适合于石斛的品种鉴别。红外光谱结合光谱检索的方法能较好的鉴别不同品种的石斛,有望成为简便、易行的植物品种鉴别方法。     

含油岩心显微红外光谱成像方法的研究

虽然用红外光谱显微探针方法研究岩心中碳质物已有很多工作,但是通常对诸如岩心等样品物性的光谱学微探针实验研究多是局限于对经过复杂处理分离出的微小样品或样品中个别位点所得的结果,缺乏对复杂样品各组分(或基团)的空间分布及其相互关系的研究。近年来新发展起来的光谱成像分析系统将光谱技术与成像技术有机地结合起来融为一体,可在光谱和空间两个方面对目标样品进行分析和识别并已得到广泛应用,但是用红外显微成像光谱研究岩心的工作则少有报道。文章报道了应用透射和衰减全反射(ATR)两种方式对含油岩心进行了显微红外光谱成像(Mapping)的研究。从灵敏度、信噪比、光谱分辨率和空间分辨率以及工作效率等方面对两种方式所得实验结果进行了比较和评估。     

油菜籽品种的红外光谱鉴别研究

用傅里叶变换红外光谱(FTIR)技术结合光谱检索的方法对油菜品种进行鉴别研究。测试了15个油菜品种75份菜籽样品的红外光谱,利用光谱软件Omnic8.0建立了两个光谱数据库Lib01和Lib02,Lib01仅云南的9个品种的平均光谱组成,Lib02由全部15个品种的平均光谱组成。未知样品光谱分别与光谱数据库Lib01进行全谱范围的相关性检索和平方微分差检索,相关性检索的正确率达到77.8%,平方微分差检索的正确率达到82.2%。未知样品光谱分别与光谱数据库Lib02进行全谱范围和指定在1 700～950 cm-1光谱范围的平方微分差检索,全谱范围的检索正确率达到82.7%,指定光谱范围的检索正确率达到90.6%。研究结果表明,FTIR结合光谱检索的方法有望成为一种简便、易行的可以鉴别油菜籽品种的方法。     

蛇足石杉及其近缘种表征关系的FTIR主成分分析

蛇足石杉是一种重要药用植物,其种内变异程度高,近缘种多,植株体型小,可供鉴别性状少。运用OMNI采样器-傅里叶变换红外光谱直接测定法,获得了蛇足石杉(Huperzia Serrata)及其5个近缘种：四川石杉(Huperzia Sutchueniana)、闽浙马尾杉(Phlegmariurus Mingchegensis)、石松(Lycopodium Japonicum)、深绿卷柏(Selaginella Doederleinii)和异穗卷柏(Selaginella Heterostachys)16个叶片样品的红外光谱,以666～3 145 cm-1范围内吸收峰吸光度为指标,以红外光谱图为对象,应用主成分分析(Principal Component Analysis),比较了16个样品在红外光谱上的差异程度。发现基于傅里叶变换红外光谱的主成分分析排序图能够在一定程度上表征16个样品的分类关系。应用FTIR直接测定法能够鉴别蛇足石杉及其近缘物种。     

红外光谱法测定天蚕茧层丝蛋白结构

本文用红外光谱法测定了天蚕暗层丝蛋白结构,发现新的天蚕茧某种程度被氧化,且河南天蚕茧比东北天蚕茧氧化更甚些。确认龙蚝天蚕不同于东北及河南天蚕茧层丝蛋白结构,而是一种新的蚕丝蛋白。用柞蚕茧氧化实验证明了东北及河南天蚕茧１５３０ｃｍ＾－１谱峰强度降低的原因及其１３２０ｃｍ＾－１和７７０ｃｍ＾－１两谱峰的由来,并对后面两个谱峰给予了归避。     

白色柞蚕茧层的光谱研究

本文用红外光变和紫外光谱研究了近年培育成功的白色柞蚕茧层，发现该白茧与传统黄褐色柞蚕茧层丝蛋白一级结构２的主体相同，白茧还残留着少量的龙胆酸与丝蛋白的交联物，交联物的残留量越少其白度越好，其中有一种白度最好，几乎与白色桑蚕茧层没有差异。     

Cu^2＋—柞蚕丝蛋白络合物的ESR研究

本文用ESR、UV和IR研究了Cu~(2 )-柞蚕丝蛋白络合物,确定了铜的价态及其配位体,给出了化学结构模型,用实验参数计算了配位键参量和配位场能.     

Stability toward alkaline hydrolysis of B. mori silk fibroin grafted with methacrylamide

Bombyx mori silk fibroin fibers were grafted with methacrylamide (MAA) and characterized by Raman and infrared (IR) vibrational spectroscopy before and after hydrolysis in NaOH 5% to elucidate the possible interactions between the two components and the stability of the fibers toward alkaline hydrolysis. Upon grafting, the fibers underwent conformational rearrangements toward a more unordered state and lost orientation at weight gains higher than 60%. Vibrational spectroscopy disclosed the occurrence of intermolecular interactions (mainly hydrogen bonds) between B. mori silk fibroin and polyMAA in the grafted fibers, and the formation of covalent bonds has been explored. These strong interactions made the grafted fibers as a whole more stable toward alkaline hydrolysis because they prevented the solubilization of the polymer upon hydrolysis and made slower the transformation of its CONH₂ groups into COOH and COO⁻ groups. Upon hydrolysis, silk fibroin underwent an enrichment in the β‐sheet crystalline domains, because of the preferential removal of the unordered domains, which were more prone to the OH⁻ attack. IR and Raman spectroscopy proved valid techniques to investigate the degradation mechanism and kinetics of grafted silk fibroin fibers and so for designing high‐performing silk‐based materials. The A₇₃₁/A₁₀₀₄ Raman intensity ratio was proposed to spectroscopically evaluate the composition of the grafted samples; its value was found to linearly increase with weight gain (R² = 0.998), envisaging the possibility of using Raman spectroscopy as a routine analytical technique for qualitative and quantitative characterization of grafted industrial samples. Copyright © 2016 John Wiley & Sons, Ltd.     

Characterization of the monoclinic form of praseodymium chromate(V)

Pure samples of the monoclinic (monazite-like) form of PrCrO₄ have been obtained for the first time and some of its properties are reported. The unit cell parameters, determined from X-ray powder diagrams, and the IR spectrum are discussed in comparison with those of some structurally related compounds.     

Influence of grafting with acrylate compounds on the conformational rearrangements of silk fibroin upon electrospinning and treatment with aqueous methanol

Silk fabrics from Bombyx mori silkworm were grafted with 2‐hydroxyethyl methacrylate (HEMA) as well as a binary system of HEMA and 4‐hydroxybutyl acrylate (HBA) and then analysed by Raman and infrared (IR) spectroscopy to elucidate the interactions between the components and their possible conformational changes. The samples were then dissolved in trifluoroacetic acid and electrospun; the influence of the grafted polymers on the silk fibroin rearrangements upon these treatments was investigated by vibrational spectroscopy. Upon grafting, the fabrics underwent conformational rearrangements towards a more unordered state, although they kept their prevailing β‐sheet conformation; also the polymeric component underwent hydrogen bonding and backbone rearrangements upon interaction with silk fibroin and the occurrence of strong covalent bonds cannot be excluded. By immersing the as‐electrospun grafted and pure fibroin nanofibres (prevalently unordered) in aqueous methanol, they partially recovered the β‐sheet content observed in the corresponding starting fabrics; the percentage of recovery decreased along the series: pure silk > HEMA‐grafted silk > HEMA and HBA‐grafted silk. This trend suggests that the presence of the polyHEMA grafted component hinders the silk fibroin recrystallization into β‐sheet upon aqueous methanol treatment; moreover, the addition of the more sterically hindered HBA monomer in the grafting system further prevented this process. Copyright © 2016 John Wiley & Sons, Ltd.     

老化丝织品的红外光谱分析研究

古代丝织品老化程度的检测有助于了解丝织品的保存状况及保护方法的选择与改进,通过红外光谱分析对丝织品老化原因及程度进行了研究。样品为经光老化、热老化和水解老化的白色丝织品和出土于湖北、内蒙古、青海的古代丝织品。对这些样品进行了显微红外分析,结果表明,红外光谱分析虽然只是提供半定量分析,但是对于发生了水解老化的丝织品来说,由于羧基含量的增加,红外分析能很容易提供定性及较好的半定量的分析结果,因此对于出土古代丝织品保存状况及老化机理的研究来说很有实用价值。     

蜘蛛牵引丝不同溶剂伸缩特性及丝蛋白构象变化的研究

动物丝纤维的特殊性能与丝蛋白的构象密切相关,本文对蜘蛛牵引丝的不同溶剂下的收缩率和水处理的构象变化进行了研究。水中蜘蛛丝收缩最大,达到50%;通过红外光谱分析,对水处理的丝蛋白的构象进行了研究,结果表明丝蛋白β折叠结构增加,而β转角变化很小。氢键受到水分子的影响高频组份与低频组份比例发生变化,进而对酰胺I谱带的C=O的振动的频率产生影响,使C=O的电子云密度降低,酰胺I频率向低频方向发生移动,这说明酰胺I的振动频率与氢键是紧密相关的。     

Environmentally friendly surface modification of silk fiber: Chitosan grafting and dyeing

In this paper, the surface modification of silk fiber using anhydrides to graft the polysaccharide chitosan and dyeing ability of the grafted silk were studied. Silk fiber was degummed and acylated with two anhydrides, succinic anhydride (SA) and phthalic anhydride (PA), in different solvents (dimethyl sulfoxide (DMSO) and N,N-dimethyl formamide (DMF)). The effects of anhydrides, solvents, anhydride concentration, liquor ratio (L:R) and reaction time on acylation of silk were studied. The polysaccharide chitosan was grafted to the acylated silk fiber and dyed by acid dye (Acid Black NB.B). The effects of pH, chitosan concentration, and reaction time on chitosan grafting of acylated silk were investigated. The physical properties show sensible changes regardless of weight gain. Scanning electron microscopy (SEM) analysis showed the presence of foreign materials firmly attached to the surface of silk. FTIR spectroscopy provided evidence that chitosan was grafted onto the acylated silk through the formation of new covalent bonds. The dyeing of the chitosan grafted-acylated silk fiber indicated the higher dye ability in comparison to the acylated and degummed silk samples. The mechanism of chitosan grafting over degummed silk through anhydride linkage was proposed. The findings of this research support the potential production of new environmentally friendly textile fibers. It is worthwhile to mention that the grafted samples have antibacterial potential due to the antibacterial property of chitosan molecules.     

Affinity of protein fibres towards sulfation

Wool, Bombyx mori and Antheraea pernyi (Tussah) silk fibres were treated with chlorosulfonic acid in pyridine and investigated by FT‐IR and FT‐Raman spectroscopies as well as mechanical measurements. The reactivity towards sulfation was found to decrease along the series: wool > Bombyx mori silk fibroin > Tussah silk fibroin, in agreement with weight gain which decreased along the same series. Accordingly, Tussah silk maintained its intrinsic tensile properties essentially unchanged upon the treatment, while for Bombyx mori silk fibroin, the tensile performance decreased sharply especially at longer reaction times. Sulfated wool was characterized by an increased fibre extensibility. New IR and Raman bands attributable to various vibrations of sulfated groups were detected in sulfated wool and to a lower extent in Bombyx mori silk fibroin fibres; all the fibres underwent conformational rearrangements upon sulfation, independent of the sulfation yield. Wool fibres treated with chlorosulfonic acid in pyridine bound considerable amounts of sulfate mainly through the hydroxyl groups of serine, threonine and tyrosine. Also, tryptophan and basic amino acids were found to participate to the reaction. B. mori silk fibroin fibres appeared to bind a minor amount of sulfate groups mainly trough the hydroxyl groups of Ser. Weight gain, spectroscopic and mechanical data are discussed in relation to the difference in fibre morphology, structure and crystallinity, as well as to the amount and accessibility of potentially reactive amino acids. Copyright © 2012 John Wiley & Sons, Ltd.