In situ FTIR diagnostics of the radio-frequency plasma decomposition of N2O

The decomposition of N₂O in a 13.56-MHz parallel-plate system was studied usingin situ Fourier transform infrared (FTIR) spectroscopy. Areas of two infrared absorption bands of N₂O recorded at 8 cm^–1 resolution were used to estimate relative gas-phase dissociation as a function of rf power and flow rate at 500 mT. Flow rate was found to strongly affect band areas over the range of powers investigated (10–90 W). The effect of rf power on band areas diminished above 40 W, probably due to poor plasma confinement. Distortion of the band shapes by the plasma permitted rotational temperatures to be estimated. Rotational temperature increased essentially linearly with power at constant flow rate, reaching 450 K at 80 W, but was independent of flow rate at constant power. Rotational temperatures were also found to depend on the temperature of the electrodes, which were heated by plasma exposure. No infrared-active product species were observed even under batch conditions where all N₂O was irreversibly dissociated. This lack of detectable products and a 50% pressure rise observed in a batch study suggest that N₂ and O₂ are the primary stable discharge products.     

Flow-through microdispenser for interfacing micro-HPLC to Raman and mid-IR spectroscopic detection

A flow-through microdispenser has been coupled to a micro HPLC separation system and used as a solvent elimination interface for Fourier transform infrared (FTIR) and Raman spectroscopic detection of the separated compounds. Using the microdispenser picoliter sized droplets can be generated and deposited on an appropriate target placed on a computerized x, y-stage. Evaporation of volatile solvent and buffer is rapid and allows analysis of the obtained dry deposits by various techniques. Due to the destruction free character of Raman and FTIR spectroscopy they can be applied sequentially to interrogate the same deposit. In the reported application five phenolic acids typically present in wine have been separated on a C-18 column technique using a mixture of water, methanol and acetic acid as mobile phase. For spectrum acquisition infrared and Raman microscopes have been used. The spectra recorded from the dried deposits of the separated compounds agreed well with the reference spectra of corresponding components.     

Solvates of Indomethacin

Indomethacin is known to exhibit polymorphism and solvates, the different forms obtained do not exhibit the same solubility and their bioavailabilities are different. It is of a prime importance to identify the various polymorphic and solvated forms. This study was carried out by: DSC (different scanning calorimetry), TG (thermogravimetric analysis), X-ray diffraction and thermomicroscopy. Seven solvates, with acetone, benzene, dichloromethane, tetrahydrofurane, propanol, chloroform and diethylether, were isolated and studied. Their formulae have been determined by thermogravimetric analysis and their X-ray patterns on powder are presented, by DSC their behaviour after desolvation is recorded, the temperature and the enthalpy of fusion are measured and by this way the form obtained is deduced. This revised version was published online in July 2006 with corrections to the Cover Date.     

Reactivity and characterisation of various rank turkish bituminous coal chars

A set of seven bituminous coal chars has been characterised by IR spectroscopy (FTIR), thermogravimetry (TG) and elemental analysis. FTIR study provided suitable information to establish differences between coal samples according to their chemical compositions. The reactivity of these samples was also studied and correlated with the coal parameters of mean vitrinite reflectance, fuel ratio and H/C ratio. The data suggest that reactivity as determined can be correlated with the mean vitrinite reflectance, fuel ratio and H/C ratio (0.90). The order of reactivity of samples were; Amasra (S1) (R _m= 0.65)>Azdavay (S4) (R _m=0.99)»Armutcuk (S2) (R _m=0.81)»Acenta (S3) (R _m=0.92)>Ac2l2k (S6) (R _m=1.11) Cay (S5) (R _m=1.03)>Sogutozu (S7) (R _m=2.14).     

纸张上光油关键物质的成分分析

利用色相色谱／质谱联用技术，傅立叶红外及裂解－气相色谱／质谱联用技术，对印刷用上光油的关键成分进行了分析，共鉴定出７种挥发性组分，２种高分子聚合物。     

尼龙1216晶型转变的红外光谱研究

采用变温红外光谱研究了尼龙1216的Brill转变并测得Brill温度约为150℃。一些α谱带在转变过程中消失，氢键强度也急剧减弱。这些现象证明了Brill转变的“局部熔融”机理。     

脲对丙烯酰胺聚合及产物结构的影响

本文研究了添加脲（添加量为丙烯酞胺的０．０６３到０．２００质量比）对丙烯酰胺聚合的影响。脲的加入能取代丙烯酞胺的双分于氢键缔合，使聚丙烯酰胺的水溶性速度提高，玻璃化温度下降。用红外光谱分析和差热分析的结构分析证实了上述机理。     

Comparison of quantitative methods for analysis of polyphasic pharmaceuticals

Adequate very sensitive quantification methods are needed for the development and are also now required for the monitoring of undesirable solid form(s) as routine tests. The pre-requisite for quantitation are selectivity, sensitivity and most important the purity of standards and their proper storage, what is a challenge for metastable forms. Several analytical techniques are available such as X-ray diffraction, spectroscopy, thermal analysis and microcalorimetry. The different steps of the validation of the analytical methods and problems to be solved are discussed. Examples illustrate the different techniques and compare their possible advantages and limits. The relative standard deviation of measurements should allow for checking the homogenization procedure of mixtures for calibration. The validation should be carried out following ICH guidelines for validation of analytical methods. Comparison of different techniques in adequate concentration range add confidence in the analytical results.     

固体超强酸SO_4~(2-)/SnO_2-Al_2O_3的红外光谱研究

以四氯化锡、硫酸铝为原料,氨水为沉淀剂,采用共沉淀法制得新型固体超强酸SO42-/SnO2-A l2O3。采用FT-IR技术考察了金属元素摩尔比、焙烧温度、浸渍液以及掺杂稀土氧化物对该固体超强酸结构和性能的影响。FT-IR结果表明在该固体超强酸中,锡和硫酸根是以螯合和桥式两种方式配位结合,其中起催化活化作用的主要是和硫酸根以螯合双齿结合的锡;和SO42-/ZrO2型超强酸相比,SO42-/SnO2-A l2O3超强酸的硫酸根FT-IR特征吸收峰发生蓝移,显示出更强的酸性。锡铝摩尔比为9∶1、焙烧温度为773K、焙烧时间为3h时,制得的SO42-/SnO2-A l2O3样品对酯化反应的催化性能最好。     

甲醇燃料车尾气净化催化剂的研究Ⅰ.甲醇深度氧化用钯催化剂上吸附物种的原位红外研究

利用原位红外技术研究了ＣＨ３ＯＨ、ＣＯ、Ｏ２等在Ｐｄ／γＡｌ２Ｏ３上的吸附情况及ＣＨ３ＯＨ和Ｏ２共吸附时表面物种的变化，结果表明：表面纯净的Ｐｄ／γＡｌ２Ｏ３催化剂对甲醇具有很好的解离吸附性能，在无氧条件下，ＣＨ３ＯＨ可在其上脱氢产生ＨＣＨＯ及ＣＯ。Ｐｄ对Ｏ２的吸附力强，氧均以解离方式吸附于Ｐｄ／γＡｌ２Ｏ３上。当吸附的［ＣＨ３Ｏ］与［Ｏ］在Ｐｄ／γＡｌ２Ｏ３上相互作用时，可产生ＨＣＨＯ、ＣＯ、甲二氧基、甲酸根等中间物种