用ATR-FTIR快速检验蔬菜表面残留抑虫琳

运用傅立叶变换衰减全反射红外光谱法(ATR-FTIR)技术对青菜表面残留的抑虫琳进行了分析。通过对蔬菜表面残留的不同浓度抑虫琳的红外光谱图的分析得出,运用ATR-FTIR技术所能检测到的抑虫琳的最低检出限为0.06 mg/cm2菜叶。并且分别采用了峰高和峰面积定量的方法进行了定量分析,两种方法的线性相关系数分别为0.9971和0.9694。实验结果表明,该分析方法能够快速检验出能引起急性中毒的药品量,并且测定过程简便,无需预处理。     

ATR-FTIR结合判别分析法快速鉴别天然柠檬风味精油种类

以5种山苍子精油、2种柠檬草精油为研究对象,采用ATR-FTIR结合判别分析法建立了几类天然柠檬风味精油的识别模型。模型清晰地将样品分成了3大类:低浓度柠檬醛精油、高浓度柠檬醛精油、烯烃类(柠檬烯及长叶烯)精油。利用模型可以简便、快速地鉴别不同类型的天然柠檬风味精油,为天然柠檬风味精油的快速鉴别提供了一种新的方法。     

Phytochemical Constituents,Attenuated Total Reflectance Fourier Transform Infrared Analysis and Antimicrobial Activity of Four Plant Leaves Used for Preparing Rice Beer in Assam,India

Phytochemicals content and antimicrobial activity of Artocarpus heterophyllus, Cyclosorus extensa, Oldendia corymbosa, and Alpinia malaccensis were investigated. Maximum alkaloids and terpenoids were found in A. heterophyllus; tannins and saponins in C. extensa; flavonoids, polyphenols, and phytosterols in O. corymbosa and anthraquinone, glycosides, and anthocyaninin A. malaccensis. Aqueous, methanolic, ethyl acetate, and hexane extracts were prepared from all the leaves. Attenuated total reflectance Fourier transform infrared spectrophotometric (ATR-FTIR) analysis revealed that alkanes and alkyl halides were prevalent in all the extracts and the ethyl acetate extracts contained comparatively higher number of functional groups, which were also more effective against Candida albicans, Escherichia coli, and Staphylococcus aureus. The minimum inhibitory concentration values of A. malaccensis against the tested pathogens were found to be lesser than the other species.     

模拟PEMFC环境下弹性体垫片材料老化研究

垫片材料的耐久性和稳定性对质子交换膜燃料电池(PEMFC)密封及其性能至关重要。采用实验的方法研究一种潜在的PEMFC垫片用材料—甲基乙烯基硅橡胶在两种模拟的PEMFC环境下的老化损伤情况。采用光学显微镜和傅里叶转换红外光谱(ATR-FTIR)技术研究试样在模拟的PEMFC环境下其表面形貌和其化学结构的老化损伤。实验结果表明:材料浸泡在模拟的PEMFC环境下发生老化损伤,试样质量损失随着老化时间的增加而增加;光学显微镜观察结果表明:试样表面形貌发生了显著变化,其老化损伤趋势表现为试样表面从光滑到粗糙,到产生微裂纹,再到裂纹扩展;ATR-FTIR实验结果表明,试样表面的化学结构发生了显著的变化。     

橡胶沥青紫外老化过程的探索

研究了橡胶沥青在紫外光老化过程中结构与性能变化规律。以软化点为指标分析橡胶沥青在紫外老化条件下性能的变化,发现其软化点增长速度慢于基质沥青,羰基、亚砜基吸收峰的变化小于基质沥青。结果表明,橡胶沥青相对基质沥青具有较强的耐紫外老化性能。     

Measurement of diffusional parameters in membranes using ATR-FTIR spectroscopy

The use of ATR-FTIR spectroscopy for the assessment of synthetic and biological membrane permeability is described. Measurement of the diffusion coefficient of acetonitrile in a polydimethylsiloxane membrane showed the method to be of reasonable reproducibility. It has been demonstrated that the concurrent measurement of both solvent and solute permeability is feasible and that the deconvolution of the diffusion and partition coefficients of these species is theoretically possible. Where the diffusing species changed the nature of the membrane a correcting normalization routine was performed by assessing the state of the membrane as a function of time. The use of this method for the routine investigation of membrane permeation phenomena has great potential for the future.     

The effect of SnO2 on enhancing electrocatalytic property of palladium toward formic acid oxidation

Although palladium (Pd) based materials are considered the best catalyst for formic acid oxidation reaction (FAOR), they are still confronted with a lot of barriers, such as the growth/sintering of Pd nanoparticles (NPs) and the accumulation of adsorbed poisoning intermediates. Herein, tin dioxide (SnO₂) decorated carbon black was utilized as the catalyst carrier to synthesize Pd/SnO₂/C for FAOR. The introduction of SnO₂ significantly reduced the particle size of Pd NPs and forming the Pd–O–Sn structure. Compared with Pd/C, Pd/SnO₂/C owned higher concentration of O_ads and less adsorption amount of poisoning intermediates. The oxygen atoms adsorbed on Pd surface were rapidly transferred to SnO₂ due to the spillover effect. The FAOR reaction kinetic results showed that the introduction of SnO₂ accelerated the diffusion rate of formic acid on the electrode surface. Pd/SnO₂/C exhibited high specific activity (5.97 mA cm⁻²), excellent durability, and high anti-CO poisoning ability toward FAOR due to the introduction of SnO₂.     

In situ spectroscopy studies of ethanol oxidation reaction using a single fuel cell/ATR-FTIR setup

This work presents a new method to study the ethanol oxidation reaction in a functional fuel cell adapting the single cell on an ATR-FTIR accessory. Using this configuration it was possible to observe the formation of the main products — acetaldehyde and acetic acid — and also measure the decay of the ethanol concentration at various temperatures. Furthermore, it was ascertained that the increment of power density with the temperature increase in the Pt/C anode fuel cell favors the acetaldehyde production. The proposed setup is a very promising characterization technique for studies of in situ electrochemical oxidation of small organic molecules.     

In situ ATR-FTIR studies of the aluminium/polymer interface upon exposure to water and electrolyte

Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) with the Kretschmann configuration was applied for in situ studies of the transport of water and ionic species through a polymer film to an aluminium/polymer interface. The time dependent intensity changes of the infrared bands of water were used to follow the transport of water to the aluminium/polymer interfacial region and a NaSCN solution was employed as model electrolyte to follow the transport and accumulation of thiocyanate ions. Apart from water sorption and ion transport, the main processes identified were corrosion/oxidation of the aluminium surface and swelling of the polymer film. The method proved to be useful for detailed in situ studies of changes at a polymer coated metal surface, such as oxidation and surface film formation on the metal. It should also be possible to study the effects of defects and pores in the polymer film on the transport properties of water and ions to the metal/polymer interface, as well as adsorption and other chemical reactions and physical interactions in the metal/polymer interfacial region.     

Quantification of trans fatty acid content in French fries of local food service retailers using attenuated total reflection – Fourier transform infrared spectroscopy

The contents of trans fatty acids in French fries served at the local food service retailers in Honolulu were determined by simple Fourier transform infrared (FTIR) spectroscopic technique without the pretreatment of fatty acid extraction. A horizontal attenuated total reflection (ATR) crystal made of zinc selenide (ZnSe) was used to obtain FTIR spectra of French fries with and without fatty acid extraction. Residual oil films obtained by pressing French fries directly on the ATR crystal surface without removal of any solid particles or air bubbles were scanned for the spectral measurement. The calibration set consisted of triolein (C18:1, 9-cis) and trielaidin (C18:1, 9-trans) mixed in varying ratios. All spectral data were averaged and converted into GRAMS format. The peak heights of each spectrum at 966 cm⁻¹ were found to be linearly correlated with the contents of trans fatty acids in the validation set (n = 8, R² = 0.9835). The developed calibration model was validated by comparing the results obtained from the ATR-FTIR with Mojonnier extraction and gas chromatography–mass spectrometry (GC–MS).