分析测试新成果(238~242)电线塑料护套的傅立叶变换红外光谱分析

采用傅立叶变换红外光谱法对21个5种不同颜色的电线塑料护套样品进行了分析.从红外光谱图中可观察到样品特征峰的峰数、峰位、相对峰面积比均有差异,但可以归纳为两大类.其中同种颜色的不同样品在红外谱图中又反映出了不同的信息,这表明在外观颜色十分相近的情况下,采用此方法能够有效的为刑事案件现场遗留的各种塑料制品提供鉴别与比对.     

鞋底材料的傅立叶变换红外光谱类型分析

利用傅立叶变换红外光谱技术对收集的29种皮鞋类黑色鞋底样品进行了测定分析,其中24种样品来自不同品牌或型号,5种样品来自同一品牌同一厂家同一批次.从红外光谱图中可以看出,依据红外光谱图中特征峰的峰数、峰位、峰形可将29个鞋底样品分为3大类.同一大类的部分鞋底样品有着相似的红外光谱特征,但在相对峰高比和指纹区中一些弱吸收峰上仍然存在明显差异.同一品牌同一厂家同一批次的鞋底样品红外光谱特征基本一致.这表明傅立叶变换红外光谱法是鉴别鞋底材料的有效方法,可以为案件现场遗留的各种鞋底材料残渣及其擦痕提供种属鉴别及比对分析.     

蒙药荜茇不同提取物的红外光谱

采用傅里叶变换红外光谱法(FT-IR)并借助于二阶导数谱研究了蒙药荜茇原药材及不同溶剂提取物(采用石油醚,95%乙醇和水)所含化学成分的红外谱图整体变化规律。结果表明:荜茇石油醚提取物的红外光谱图可见羰基的吸收峰(1722 cm~(-1))和亚甲基的吸收峰(2927和2855 cm~(-1))比较强,说明其中所含大量的小分子萜类、脂肪酸(酯)等低极性成分;95%乙醇提取物中可能含有芳酮类化合物及糖苷类化合物。水提取物中主要含鞣质及多糖类成分。FT-IR能够简便、快速地提供蒙药不同提取物中主要化学成分的信息,可对其主体成分进行初步的识别,为制定下一步的提取方案和检测方法提供了方向性参考。     

芽胞杆菌全细胞热裂解气相色谱聚类分析

通过热裂解气相色谱对１４ 个芽胞杆菌模式菌株全细胞进行分析, 确定芽胞杆菌不同属间特征性谱峰;利用ＳＴＡＴＩＳＴＩＣＡ 系统对热裂解气相色谱图中３０ 个主要谱峰进行聚类分析, 绘制出的树状谱清楚地表明各菌株间的亲缘关系。     

检测器(Ⅲ)

（续上期）3.3氖灯的问题紫外检测器中氖灯问题是一个令人头痛的问题。现代检测器中用于启辉和维持氖灯工作的电路比较复杂，电路部分通常还要检测氖灯是否已经工作，如果没有工作，电路系统将继续启辉氖灯。图3的情况正是说明了这一现象。色谱分析中希望的出峰时间是12min左右，但如果同时还出现了4个方形峰，这4个方形峰就是电路系统连续启辉氖灯造成的（图3－a），换只新的氛灯后色谱图就正常了（图3－b）。氖灯寿命和能量又是另一个问题。通常的氖灯寿命是在1000～2000h，但是并不是绝对的。有的氖灯在使用几百小时后，检测器的噪声水平…     

衰减全反射红外光谱法测定电工胶带粘合剂

采用衰减全反射傅里叶变换红外光谱法(ATR-FTIR)对31个品牌电工胶带的粘合剂进行分析,通过红外特征吸收峰确定粘合剂的主要成分均为天然橡胶和丁苯橡胶混合物,不同品牌的样品通过红外光谱定性分析无法区分。通过OPUS软件分别选择天然橡胶和丁苯橡胶的红外特征吸收峰进行峰面积积分,计算两种物质特征峰面积的相对比例,采用单因素方差分析确定不同样品天然橡胶和丁苯橡胶特征峰面积的相对比例是否存在统计学差异,然后采用最小显著性差异法进行验后多重比较,分析特征峰面积相对比例存在统计学差异的品牌。31个品牌电工胶带组成的465组样品对中有422组可以区分,区分率达到90.8%。结果表明,通过红外光谱定量分析可实现不同品牌电工胶带粘合剂的区分。     

傅里叶变换红外光谱法鉴别黑色签字笔油墨种类

采用傅里叶变换红外光谱法对不同产地、不同牌号及同一牌号不同型号的122种黑色签字笔字迹进行了种类鉴别.以乙腈一水以体积比60比40作为提取剂,分别对122种黑色签字笔字迹进行了提取,根据提取效果的不同,分为可溶(63种)和不可溶(59种)两大类.然后对黑色签字笔字迹进行了傅里叶变换红外光谱测定,根据红外光谱图中特征峰数目的不同,吸收峰的峰位及峰面积比或峰高比的异同进一步进行区分,从而达到对黑色签字笔字迹油墨进行种类鉴别.对红外光谱测定的有关因素如:与溴化钾混合及压片的试样制备,写有字迹纸张的质量,以及不同波长及时间的紫外光照等也作了试验.     

纳米/微米碳酸钙的结构表征和热分解行为

采用棕榈酸对纳米碳酸钙进行有机表面改性, 运用SEM﹑TEM、XRD、FTIR 及TG-DTG 对表面改性前后的纳米碳酸钙进行表征, 并与微米碳酸钙的微晶结构及热分解特性进行比较. FTIR 分析结果确证了棕榈酸与纳米碳酸钙表面是以化学键合和物理吸附方式相结合, 粒子表面存在羧基等有机官能团的红外吸收特征. 对比研究发现, 碳酸钙微晶纳米化后, 其红外V3特征吸收峰出现约35 cm-1 的蓝移现象, 并且明显窄化. 初步解释了纳米碳酸钙红外吸收峰蓝移的原因, 认为尺寸效应和晶体场效应是影响纳米碳酸钙红外光谱特征的主要因素. 微晶结构的变化使得纳米碳酸钙的热分解反应表现出反常特性, 热分解温度较微米碳酸钙下降了40.6 ℃.     

尿毒症患者血清及正常人尿液内中分子物质的分离分析

采用凝胶色谱法，以２０６ｎｍ处的紫外吸收为检测手段，分别从尿毒症患者血 清及正常人尿液内分离出Ａ，Ｂ两个中分子峰，而从正常人血清中分离出来的Ａ峰远低 于尿毒症患者血清的Ａ峰；在Ｂ峰的位置正常人血清未出现明显的吸收．运用该方法 不仅提高了凝胶色谱的分离效果，且能方便地得到中分子级分的纯品．对清除了淋洗 液组分的中分子级分进行紫外和红外扫描，结果发现来源于尿毒症患者血清及正常人 尿液的Ａ峰物质具有相同的紫外吸收且红外吸收光谱极其相似，而不同来源的Ｂ峰物 质虽然紫外吸收相同，但它们的红外吸收却存在一定的差异．采用离子交换色谱法对Ｂ 峰物质进行进一步的分离，以２３０ｎｍ处的紫外吸收为检测手段，正常人尿液的Ｂ峰物 质被分离成１７个亚峰，尿毒症血清的Ｂ峰物质被分离成１３个亚峰．其中绝大部分亚峰 的出峰位置（洗脱体积）相同．     

阳极溶出催化极谱法测定微量金的研究

使用阳极溶出催化极谱法测定某些元素已成为可能,但在测定金的方面尚未见报导。采用溶出催化极谱法通常可使峰电流提高数十倍到数百倍,因而能大大提高测定灵敏度。在普通极谱仪上测不出的溶出电流,经催化后,可以明显地观察到溶出催化电流。金的溶出催化原理是:三价金在一定条件下经阴极极化以元素态被电解沉积在玻璃碳电极表面上,之后在含有氯化亚锡的催化体系中进行阳极溶出,被电氧化下的金离子又很快被氯化亚锡还原成为元素态金,并在电极上再被电氧化,如此反复,使有限的金能循环使用,从而提高了峰电流(见图1)。     

亚甲基富勒烯衍生物[6,6]-苯基-C61丁酸甲酯的密度泛函研究

运用密度泛函理论和含时密度泛函理论研究了亚甲基富勒烯衍生物[6,6]-苯基-C61丁酸甲酯(PCBM)的几种物理化学性质, 包括几何结构、电子结构、电荷布居与成键, 以及IR、Raman和电子吸收光谱. 自然键轨道方法的结果表明, 大约有0.11个电子通过成键由分子的一部分苯基和丁酸甲酯基团(电子给体)转移到富勒烯笼(电子受体). 最强的IR和Raman谱峰来自于不同的振动模式, 分别位于1773和1492 cm-1处. 计算的各向同性极化率、极化率各向异性不变量以及超极化率分别是577.7、96.9、-22.8 a.u.. 基于含时密度泛函理论计算并分析了PCBM的电子吸收谱, 在349 nm处的吸收峰与实验结果符合很好.     

亚甲基富勒烯衍生物[6，6]-苯基-C61丁酸甲酯的密度泛函研究

运用密度泛函理论和含时密度泛函理论研究了亚甲基富勒烯衍生物[6.6]-苯基-C61丁酸甲酯(PCBM)的几种物理化学性质,包括几何结构、电子结构、电荷布居与成键,以及IR、Raman和电子吸收光谱.自然键轨道方法的结果表明,大约有0.11个电子通过成键由分子的一部分苯基和丁酸甲酯基团(电子给体)转移到富勒烯笼(电子受体).最强的IR和Raman谱峰来自于不同的振动模式,分别位于1773和1492 cm-1处.计算的各向同性极化率、极化率各向异性不变量以及超极化率分别是577.7、96.9、-22.8 a.u..基于含时密度泛函理论计算并分析了PCBM的电子吸收谱,在349 nm处的吸收峰与实验结果符合很好.     

DFT Study on Methanofullerene Derivative [6,6]-Phenyl-C61 Butyric Acid Methyl Ester

Density functional theory (DFT) and time-dependent density functional theory (TDDFT) with hybrid functional B3LYP were used to investigate several physical and chemical properties of [6,6]-phenyl-C₆₁ butyric acid methyl ester (PCBM), including the geometry, electron structure, charge population, bond properties, as well as IR, Raman and electronic absorption spectra. The analysis of the natural bond orbital (NBO) suggested that there were about 0.11 electrons transferred from moiety phenyl and butyric acid methyl ester group of PCBM to fullerene cage. The strongest IR and Raman peaks came from different modes with the frequencies of 1773 and 1492 cm⁻¹, respectively. The calculated isotropic polarizability, polarizability anisotropy invariant, and hyperpolarizability were 577.7, 96.9, and −22.8 a.u., respectively. Based on TDDFT, the electronic absorption spectra of PCBM were calculated and analyzed. The calculated absorption band near 349 nm agreed well with the experimental measurement.     

The chemical bonding and spectral assignments of rhodium(III)‐catalyzed closo‐dodecaborate complexes: Ab initio study

The chemical bonding and spectral assignments of rhodium(III)‐catalyzed closo‐dodecaborate (RhCD) complex are systematically studied using the density functional theory calculations. It is found that the calculated main bond lengths of framework are in good agreement with experimental X‐ray observation, and the pronounced hybridization of B‐2p and Rh‐4d states is responsible for the structural stability, reflected by the large dissociation energy and HOMO–LUMO energy gap. The AdNDP chemical bonding analysis indicates that the RhCD complex can be stabilized by two H‐bridged 3c‐2e σ‐bonds (B‐H‐Rh triangles). Additionally, the theoretical calculations reproduce well the main experimental IR spectrum, and the characteristic peaks are properly assigned. These results will be helpful for further insight into the unique electronic structure of the species, and provide valuable references for potential applications in novel materials.     

Spectral analysis of acetylcholine halides by density functional theory calculations

The optimized molecular structures, vibrational frequencies and ¹H and ¹³C NMR chemical shifts of acetylcholine halides (F, Cl, and Br) have been investigated using density functional theory (B3LYP) method with 6-311G(d) basis set. The comparison of their experimental and calculated IR, R and NMR spectra of the compounds has indicated that the spectra of three optimized minimum energy conformers can simultaneously exist in one experimental spectrum. Thus, it was concluded that the compounds simultaneously exist in three conformations in the ground state. The calculated optimized geometric parameters (bond lengths and bond angles), vibrational frequencies and NMR chemical shifts for the minimum energy conformers were seen to be in a good agreement with the corresponding experimental data. All the assignments of the theoretical frequencies were performed by potential energy distributions using VEDA 4 program.     

环氧丙烷在金属氧化物表面上吸附的IR研究

环氧丙烷(PO)是一种重要的化工原料,可用于合成多种特殊化学品及材料[1].其中在某些化学品合成过程中,经常以均相酸或碱作催化剂,例如在合成有机溶剂丙二醇醚的过程中就用到了矿物酸或苛性碱.虽然均相酸或碱作催化剂有活性高、选择性好等优点,但同时存在产物与催化剂分离、腐蚀和废液处理等多种弊端,因此在一些反应过程中人们正积极探求用符合要求的多相催化法来代替均相催化法.A l2O3、ZnO和MgO分别具有酸性、两性和碱性并已用于多种催化反应中[2,3],本文通过IR光谱法研究了环氧丙烷在MgO,A l2O3和ZnO上的吸附活化态.在这些氧化物中…     

From Infrared Spectra to Macroscopic Mechanical Properties of sH Gas Hydrates through Atomistic Calculations

The vibrational characteristics of gas hydrates are key identifying molecular features of their structure and chemical composition. Density functional theory (DFT)-based IR spectra are one of the efficient tools that can be used to distinguish the vibrational signatures of gas hydrates. In this work, ab initio DFT-based IR technique is applied to analyze the vibrational and mechanical features of structure-H (sH) gas hydrate. IR spectra of different sH hydrates are obtained at 0 K at equilibrium and under applied pressure. Information about the main vibrational modes of sH hydrates and the factors that affect them such as guest type and pressure are revealed. The obtained IR spectra of sH gas hydrates agree with experimental/computational literature values. Hydrogen bond’s vibrational frequencies are used to determine the hydrate’s Young’s modulus which confirms the role of these bonds in defining sH hydrate’s elasticity. Vibrational frequencies depend on pressure and hydrate’s O···O interatomic distance. OH vibrational frequency shifts are related to the OH covalent bond length and present an indication of sH hydrate’s hydrogen bond strength. This work presents a new route to determine mechanical properties for sH hydrate based on IR spectra and contributes to the relatively small database of gas hydrates’ physical and vibrational properties.     

侧链含酞菁铜功能基的聚苯胺的制备与性能研究

以酞菁铜、氯磺酸和氯化亚砜为原料合成酞菁铜磺酰氯,并将其与本征态聚苯胺进行反应,合成了侧链悬挂酞菁铜功能基的聚苯胺(PAnCuPc).用元素分析、红外光谱和紫外-可见吸收光谱对产物和反应中间体进行了结构表征.PAnCuPc可溶于强极性非质子溶剂.如NMP,DMF,DMSO和DMAc,甚至在常用的低沸点溶剂如THF和三氯甲烷中也有一定的溶解性.红外光谱研究表明,与本征态聚苯胺相比,侧链含酞菁铜功能基的聚苯胺的吸收峰向低频方向移动.紫外-可见吸收光谱表明,侧链悬挂酞菁铜功能基的聚苯胺在可见光区和近红外区都具有较强的吸收.透射电镜和X射线衍射研究表明,该产物具有较强的结晶性能.     

Structural, photophysical, and nonlinear absorption properties of trans-di-arylalkynyl platinum(II) complexes with phenyl and thiophenyl groups

Optical power limiting and luminescence properties of two Pt(II) complexes with thiophenyl and phenyl groups in the ligands, trans-Pt(P(n-Bu)3)2(C[triple bond]C-Ar)2, where Ar = -C4H2S-C[triple bond]C-p-C6H4-n-C5H11 (1) and -p-C6H4-C[triple bond]C-C4H3S (2), have been investigated. The fluorescence lifetimes were found to be on the sub-nanosecond time scale, and the quantum yields were low, in accord with fast intersystem crossing from the excited singlet to triplet manifold. The phosphorescence lifetimes of 1 and 2 were shorter than that of a Pt(II) complex having two phenyl groups in the ligands. In order to elucidate the C-Pt bonding nature in the ground state, the 13C NMR chemical shift of the carbon directly bonded to Pt, the coupling constants 1JPtC, 2JPtC, and 1JPtP, and IR nuC[triple bond]C wavenumbers were obtained for 1, 2, and three other trans-diarylalkynyl Pt(II) complexes. X-ray diffraction data of 1 and 2 and density functional theory calculated geometries of models of 1, 2, and trans-Pt(P(n-Bu)3)2(C[triple bond]C-p-C6H4-C[triple bond]C-C6H5)2 (3) show that 1 preferably exists in a different conformation from that of 2 and 3. The variations in photophysical, NMR, and IR data can be rationalized by differences in geometry and pi-backbonding from Pt to the alkynyl ligand.     

2D NMR方法研究抗癌药物冬凌草乙素的结构与谱线归属

用异核化学位移相关谱、远程异核化学位移相关谱和同核化学位移相关谱等现代核磁共振技术对抗癌中草药冬凌草中分离出的抗癌、抗菌有效成分冬凌草乙素分子的~(13)C和~1H化学位移进行了完全归属,为冬凌草乙素分子溶液中的三维空间结构研究提供了可靠的结构参数。