Flash Pyrolysis Study of MnTC and NiCT by Using T-Jump/FTIR Spectroscopy

Flash pyrolysis of MnTC（ [Mn2（TNR）2（CHZ）2（H2O）4]·2H2O） and NiCT（ [Ni（CHZ）3]（TNR）·5H2O） is conducted by using T-jump/FTIR spectroscopy under 0.1 MPa Ar atmosphere. The mole fractions of the individual products in the pyrolysis gas mixture are described as a function of time. Results show that NiCT appears to produce more N2O, NH3 and HONO upon flash pyrolysis, thus secondary oxidation reduction reactions may take place to a certain extent during its thermal decomposition, which in turn leads to unsteady combustion and possibly to failure of the device. While H2O and CO2 are the major two gas products of flash pyrolysis of MnTC, it warrants further in-depth trials for the adoption in detonators as coo-friendly and chemically compatible primary explosive. The two compounds both liberate volatile metal carbonate, oxide and isocyanate compounds.

Molecular structure characterization of middle-high rank coal via^(13)C NMR,XPS,and FTIR spectroscopy

Elemental analysis,nuclear magnetic resonance carbon spectroscopy(^(13)C-NMR),X-ray photoelectron spectroscopy(XPS)and Fourier transform infrared spectroscopy(FTIR)experiments were carried out to determine the existence of aromatic structure,heteroatom structure and fat structure in coal.MS(materials studio)software was used to optimize and construct a 3D molecular structure model of coal.A method for establishing a coal molecular structure model was formed,which was“determination of key structures in coal,construction of planar molecular structure model,and optimization of three-dimensional molecular structure model”.The structural differences were compared and analyzed.The results show that with the increase of coal rank,the dehydrogenation of cycloalkanes in coal is continuously enhanced,and the content of heteroatoms in the aromatic ring decreases.The heteroatoms and branch chains in the coal are reduced,and the structure is more orderly and tight.The stability of the structure is determined by theπ-πinteraction between the aromatic rings in the nonbonding energy EN.Key Stretching Energy The size of EB determines how tight the structure is.The research results provide a method and reference for the study of the molecular structure of medium and high coal ranks.

利用ATR-FTIR研究脂质纳米粒的鼻黏液渗透性

鼻黏液是影响疫苗和药物经鼻吸收的首要屏障。由于干扰因素复杂多变,在体评价黏液渗透性较难实施,多采用体外评价。现有的药物鼻黏液渗透性检测方法如细胞模型法、多粒子示踪技术等,存在细胞培养周期长、操作繁琐、成本高、可获得信息少且需要进行荧光标记等不足,对鼻黏膜制剂的体外评价具有很大的局限性,因此迫切需要建立一种快速、简便、灵敏的鼻黏膜制剂黏液渗透性评价方法。基于衰减全反射-傅里叶红外光谱(ATR-FTIR)对药物结构以及粘蛋白二级结构变化的敏感性,利用其对不同性质(粒径与电荷)脂质体的鼻黏液渗透性进行研究,通过FTIR图谱分析不同脂质纳米粒与黏液中粘蛋白的相互作用,建立了鼻黏膜制剂黏液渗透性的体外评价方法。方法学研究表明,对于聚乙二醇10000(PEG10000)、壳聚糖、海藻酸钠脂质体,该方法线性关系分别为Y=2.3866X+2.154、Y=1.8703X+0.2789、Y=1.13014X+0.0609,线性相关系数分别为0.9958、0.9945、0.9909,精密度RSD值分别为0.62%、0.73%、0.95%;重复性试验中RSD值分别为0.83%、0.97%、0.88%,说明该方法线性关系良好、精密度高、重复性好,可用于体外评价药物制剂在黏液中的渗透性。研究结果表明,利用ATR-FTIR在不同时间内扫描样品可得到不同脂质体制剂样品的强度增加的吸收带。对于不同粒径PEG脂质体而言,粒径越小其黏液渗透性越强;对于不同电荷脂质体而言,壳聚糖脂质体黏液渗透性最弱,海藻酸钠次之,PEG脂质体黏液渗透性最强。进一步研究表明,不同电荷脂质体黏液渗透性的差异源于其与粘蛋白相互作用,该结论可通过分析粘蛋白酰胺Ⅰ带所包含的各二级结构信息得到。综上,基于ATR-FTIR所建立的体外评价方法灵敏简便,可作为多种不同制剂的鼻黏液渗透性的快速测定,经改进后还可用于药物制剂在其他黏液中的渗透性评价,应用前景广阔。

Flash Pyrolysis Study of M2TNR （M： Carbohydrazide or Semicarbazide） by T-jump/FTIR Spectroscopy

Flash pyrolysis of （CHZ）2TNR and （SCZ）2TNR was conducted by T-jump/FTIR spectroscopy under 0.1 MPa Ar atmosphere. The results show that eleven IR-active gas products obtained during flash pyrolysis process of the two title compounds are NO, CO, HCN, NH3, NO2, N2O, HNCO, HNO2, CO2, H2O and HCHO, of which NO and CO are the main gas products. The molar fraction of the individual product in the pyrolysis gas mixture was described as a function of time. At least some of the NO2, N2O and H2O can result from the oxidization reaction of NH3 during flash pyrolysis of （CHZ）2TNR. It can be concluded that the two compounds are not worthy of further in-depth consideration of the adoption in detonators as eco-friendly primary explosive, and should not be used as gas generation composition of automobile crash airbag system taking into account the toxicity.

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。

T-Jump/FTIR技术研究3,4-二硝基呋咱基氧化呋咱快速热裂解

采用温度快速跃迁原位池与快速扫描傅里叶变换红外联用(T-Jump/FTIR)技术在0.1-0.4MPa压强范围内研究了3,4-二硝基呋咱基氧化呋咱(DNTF)的快速热裂解.试验是以1000℃·s-1的升温速率在800和1000℃的温度下进行,用快速扫描傅里叶变换红外光谱实时跟踪分析DNTF裂解的气相产物.结果表明,DNTF快速热裂解的主要产物CO、CO2、NO和NO2的相对摩尔浓度c*与温度和压强有关,通过分析相对摩尔浓度比(c*NO/c*NO2)随温度和压强的变化,揭示了DNTF中碳硝基C—NO2存在均裂生成NO2和异构化生成NO两条竞争分解的可能途径,同时压强可能抑制呋咱环和氧化呋咱环生成NO的可能性.压强升高使c*CO和c*CO2升高,而使c*CO/c*CO2下降,证明DNTF的分解中存在非均相的气相/凝聚相反应和均相的气相产物间反应的二次或三次过程.

T-JUMP/FTIR联用技术研究RDX的热裂解过程

用T-JUMP/FTIR技术研究了模拟燃烧条件下RDX的热裂解过程。通过分析裂解产物随时间的分布规律及温度与压力对裂解过程的影响,提出了RDX可能的快速热裂解机理及影响快速热裂解机理的因素。结果表明,RDX裂解气相产物主要有CO2、N2O、NO2、HNCO、NO、CO和HCN,且在不同的测试条件下产物的相对含量有明显变化:在600℃、0.1～0.4MPa条件下,裂解5s以内的NO2与NCN含量比随压力的升高而下降;HCN与N2O含量比随压力的提高而增大;在0.1MPa压力条件下,随着温度的升高,HCN与N2O的含量比趋向于增大。RDX快速热裂解的初期存在两个竞争反应,即C—N和N—N键的断链竞争反应;提高温度和在0.1～0.4MPa压力范围内提高压力对生成HCN的N-N键断裂反应有利。

FTIR Spectroscopic Study of Broad Bean Diseased Leaves

[Objective] The aim was to indentify diseased leaves of broad bean by vibra- tional spectroscopy. [Method] In this paper, broad bean rust, fusarium rhizome rot, broad bean zonate spot, yellow leaf curl virus and normal leaves were studied using Fourier transform infrared spectroscopy combined with chemometrics. [Result] The spectra of the samples were similar, only with minor differences in absorption inten- sity of several peaks. Second derivative analyses show that the significant difference of all samples was in the range of 1 200-700 cm2. The data in the range of 1 200- 700 cm＇ were selected to evaluate correlation coefficients, hierarchical cluster analy- sis （HCA） and principal component analysis （PCA）. Results showed that the correla- tion coefficients are larger than 0.928 not only between the healthy leaves, but also between the same diseased leaves. The values between healthy and diseased leaves, and among diseased leaves, are all declined. HCA and PCA yielded about 73.3% and 82.2% accuracy, respectively. [Conclusion] This study demonstrated that FTIR techniques might be used to detect crop diseases.

Comparison Between Conventional Convective Heating and Microwave Heating: An FTIR Spectroscopy Study of the Effects of Microwave Oven Cooking of Bovine Breast Meat

The effects of microwave energy and conventional convective heating on bovine meat were studied in the mid-infrared region by FTIR spectroscopy, to highlight the differences between the two cooking methods. Samples of 100 g of bovine breast meat were cooked using three treatments: heating in a conventional electric oven at the temperature of 165°C for 16 min, heating in a microwave oven at 800 W for 95 sec, and heating in the same microwave oven at 650 W for 160 sec. Significant decreases in intensity of vibration bands of CH2 methylene group at 1921 and 1853 cm-1 and of the carbonyl band at 1742 cm-1 were observed after microwave heating with respect to heating in a conventional oven, showing that Maillard reaction occurs partially using microwave oven. Spectral analysis in the amide I region after microwave cooking at 800 W for 95 sec showed that an increase in intensity occurred in the region from 1665 to 1690 cm-1 which can be attributed to β-turns, characteristic of disorder processes in the protein. Further analysis after microwave cooking at 650 W for 160 sec evidenced major increase in intensity of β-turns content and the appearance of significant increases of β-sheet component at 1635 cm-1 and 1695 cm-1 that can be attributed to aggregated β-sheets structures.

Approaching intermolecular interactions and membrane activity of taxol by FTIR Spectroscopy-implications for anticancer therapeutics

We studied the incorporation of hydrophobic drug Taxol into a solid lipid matrices by FTIR spectroscopy. Lipid arrays containing different molar fractions of the drug were made and deposited on the spectrometer glass window substrates for obtaining multilayer stacks. The drug induced an alteration of lipid array spacings, indicating the drug-lipid recognition. Using excess amounts of Taxol provide information on extrapolations on its cellular solubility in biomembranes. The data obtained could be used further for developing novel anticancer drug formulations, as well as for elucidating its novel cellular pharmacological targets.

Authentication of <i>Rothmannia whitfieldii</i>Dye Extract with FTIR Spectroscopy

Extraction of dye from dry fruit of Rothmannia whitfieldii was carried out using four different extraction methods. Solvent and acid extraction methods gave a colourless supernatant solution after extraction time of 45 minutes at 60°C. The alkali method gave a deep brown coloured supernatant solution while the aqueous method gave a dark coloured supernatant solution after extraction under the same conditions. From the result of the FTIR spectroscopy characterization of the coloured solutions and the dry powder of Rothmannia whitfieldii fruit, it was observed that only the alkali method extracted what can be called a dye with likely presence of tannins. The result also showed that the possible functional groups present in the supernatant solution after aqueous extraction are same with the functional groups present in the dry pulverized Rothmannia whitfieldii fruit. Hence, aqueous method did not extract any dye. Similarly, a mixture of the solution after aqueous extraction with drops of alkali solution produced a deep brown coloured solution indicating solubility of the dye component in alkali media.

Waveband Selection with Equivalent Prediction Performance for FTIR/ATR Spectroscopic Analysis of COD in Sugar Refinery Waste Water

The level of chemical oxygen demand(COD)is an important index to evaluate whether sewage meets the discharge requirements,so corresponding tests should be carried out before discharge.Fourier transform infrared spectroscopy(FTIR)and attenuated total reflectance(ATR)can detect COD in sewage effectively,which has advantages over conventional chemical analysis methods.And the selection of characteristic bands was one of the key links in the application of FTIR/ATR spectroscopy.In this work,based on the moving window partial least-squares(MWPLS)regression to select a characteristic wavelength,a method of equivalent wavelength selection was proposed combining with paired t-test equivalent concept.The results showed that the prediction effect of the selected wavelength was very close to that of the MWPLS method,while the number of wavelength points was much smaller.SEPAve,RP,Ave,SEPStd,and RP,Std which characterized the modeling effect were 26.3 mg L^-1,0.969,3.49 mg L^-1,and 0.006,respectively.The validation effect V-SEP and V-RP were 28.64 mg L^-1 and 0.960,respectively.The selected waveband was between 1809 cm^-1 and 1568 cm^-1.The method was of more reference value for the design of FTIR/ATR spectral instrument for COD detection.

FTIR Spectroscopic Studies on Molecular Interaction between Alcohols and N,N-dimethylacetamide

The association between alcohols and N,N-dimethylacetamide in carbon tetrachloride was investigated using FTIR spectroscopy at 298 K.The formation constants for 1∶1 and 1∶2 complexes were calculated using the method of Whetsel and Kagarise.The observed 1∶1 complex values were also verified using the method of Nash.The rate of change in C=O bond moment on complexing with alcohols increased with increasing acidity of alcohols.The formation constant and values of free energy change increased with the increase in carbon chain length of alcohols,which suggested that the degree of complex formation varied with the length of the carbon chain of alcohols.

FTIR spectroscopic study of electrochemical flotation of jamesonite-diethyldithiocarbamate system

The flotation behavior of jamesonite was investigated with sodium diethyldithiocarbamate(DDTC) as a collector. The results show that jamesonite has good floatability from pH 2 to pH 13. The flotation of jamesonite is also dependent on the pulp potential. The potential-pH range for jamesonite flotation is established. The FTIR spectroscopy analysis shows that the major adsorption product of sodium diethyldithiocarbamate on jamesonite is lead diethyldithiocarbamate. The intensity of the FTIR signals of metal diethyldithiocarbamate adsorption on jamesonite and the flotation response of jamesonite are correlated with the pulp potential.

Synchrotron FTIR spectroscopy reveals molecular changes in Escherichia coli upon Cu^2＋ exposure

Copper ions(e.g.,Cu^(2+)) have outstanding antibacterial properties,but the exact mechanism is rather complex and not fully understood.In this work,synchrotron Fourier transform infrared(FTIR) spectroscopy was used as an analytical tool to investigate the CuCl_2-induced biochemical changes in Escherichia coli.Our spectral measurements indicated that this technique is sensitive enough to detect changes in membrane lipids,nucleic acids,peptidoglycans and proteins of Cu^(2+)-treated bacteria.Interestingly,for short-time treated cells,the effects on phospholipid composition were clearly shown,while no significant alterations of proteins,nucleic acids and peptidoglycans were found.PeakForce quantitative nano-mechanics mode atomic force microscopy(AFM)confirmed the changes in the topography and mechanical properties of bacteria upon the Cu^(2+) exposure.This study demonstrated that FTIR spectroscopy combined with AFM can provide more comprehensive evaluation on the biochemical and mechanical responses of bacteria to copper.

FTIR Spectroscopic Study of Crystallization of Uniaxial Drawn Syndiotactic Polystyrene/Carbon Nanotube Nanocomposite Films

The crystallization of uniaxial hot drawn syndiotactic polystyrene/multi-walled carbon nanotube （sPS/MWCNT） nanocomposite films was studied by FTIR spectroscopy. The effects of MWCNT content, draw ratio and drawing temperature on the sPS crystallinity were investigated. The sPS/MWCMT nanocomposite films show reduced crystallinities with the increase of MWCNT content. In addition, with the increase of draw ratio, both the pure sPS and the sPS/MWCNT nanocomposite drawn films exhibit increased crystallinity. The effect of drawing temperature on the sPS crystallization is complex. In a temperature range of 100―135 °C, the crystallinity decreases with drawing temperature, whereas it increases at 140 °C for both pure sPS and its nanocomposite films.

In situ and operando infrared spectroscopy of battery systems:Progress and opportunities

In situ and operando infrared spectroscopies are powerful techniques to support the design of novel materials for batteries and the development of new battery systems.These techniques can support the study of batteries by identifying the formation of new species and monitoring electrochemical energy stability.However,few works have employed these techniques,which can be used to investigate various materials,including systems beyond lithium-ion technology,in the research of batteries.Therefore,this review presents a comprehensive overview focusing on the main contributions of in situ and operando infrared spectroscopy for lithium-ion batteries(LIBs)and other battery systems.These techniques can successfully identify the formation of species during the electrolyte reduction,electrode degradation,and the formation of the solid-electrolyte interphase(SEI)layer.From these outcomes,it is possible to conclude that this characterization approach should be employed as a protocol to overcome remaining issues in batteries,consequently supporting battery research.This review aims to be a guide on how infrared spectroscopy can contribute to monitoring battery systems and to lead researchers interested in applying this technique.

In Situ FTIR Spectroscopic Study of Electrochemical Adsorption of Phosphate Ions on Gold

Infrared reflection-absorption spectra for primary, secondary and tertiary orthophosphate anions on a gold electrode in aqueous solution were studied by in situ FTIR spectroscopy. The spectra show that H2PO4- , HPO ions do not interact with the electrode surface as strong as PO do. According to the surface selection rule, we deduce the modes of adsorption of these anions on the electrode from these spectra. The experiment also confirms the affection to adsorption of ion on the electrode due to ion-migration into thin-layer cavity.

聚乙烯微塑料对青稞幼苗生长影响的FTIR光谱研究

利用傅里叶变换红外光谱(FTIR)结合二阶导数红外光谱(SD-IR)对在富含聚乙烯微塑料环境下生长的青稞幼苗进行研究。结果显示,青稞幼苗的一维原始光谱整体相似,主要由蛋白质、糖类和脂质的吸收峰组成。在二阶导数红外光谱中,不同条件下生长的青稞幼苗在1800~800 cm^(-1)范围内的吸收峰强度和形状展现出差异。结果显示,与对照组相比,在富含聚乙烯微塑料环境下生长的青稞幼苗的多糖、蛋白质和脂质含量发生了变化。结果表明,傅里叶变换红外光谱结合二阶导数光谱能够有效监测微塑料对青稞幼苗生长的影响。

ATR-FTIR结合DSC法快速鉴别食品接触用塑料包装制品

研究了一种衰减全反射红外光谱(ATR-FTIR)结合差示扫描量热法(DSC)快速鉴别食品接触用塑料包装制品单一材质的方法。红外光谱图能准确反应塑料制品的内部结构,结合DSC曲线得出其具体成分。该方法快速、准确且几乎不破坏样品。