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Benzene is an omnipresent liquid in industries. The occupational exposure to benzene leads to the urinary excretion of benzene metabolites, viz., phenol, pyrocatechol, hydroquinone, and trihydroxybenzene, due to its biotransformation. These metabolites are phenolic in nature and considered as immediate biomarkers of benzene exposure. The present work includes the separation and determination of urinary phenolic benzene metabolites by coupling two different techniques. Thin-layer chromatography (TLC) was used as the separation technique to get individually separated spots of all four metabolites, which were further quantified by ultraviolet (UV)–visible spectroscopy at 765 nm. For the development of the separated spots on TLC plate and determination of metabolites by UV–visible spectroscopic method, alkaline Folin‒Ciocalteau reagent was used. Folin‒Ciocalteau reagent is having wide applications for phenol determination and gives blue color with almost all types of phenols. The colored solutions were measured against the blank disk taken from the developed spots on plastic TLC plate. Based on the obtained results, a simple, rapid, and sensitive method for the quantitation of urinary phenolic benzene metabolites has been developed and validated according to the International Conference on Harmonization (ICH) guidelines. The validated method was efficaciously applied to cigarette smokers and petrol station workers, and it was found that the method has favorable application in the routine analysis of urine samples of benzene-exposed population.

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JPC - Journal of Planar Chromatography - Modern TLC
Authors: Qing Zhu, Haijun Wu, Fang Wang, Anqi He, Kun Huang, Yongju Wei, Cuige Liu, Yanjun Zhai, Shifu Weng, Zhanlan Yang, Yizhuang Xu, Isao Noda, and Jinguang Wu

655 J.G. Wu , Modern FTIR Spectroscopy, Technology and Application, Science and Technology Press, Beijing, 1994. Wu J

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-infrared spectroscopy as an index of brain and tissue oxygenation. Br. J. Anaesth. 103 (Suppl. 1.), i3–i13 (2009) Arango M Near-infrared spectroscopy as an index of brain and tissue oxygenation Br. J. Anaesth. 2009 103

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. However, in recent years, the use of infrared spectroscopy as a method of characterisation of crystallinity has grown in prominence. In the case of PCL, one of the first and often cited studies concerned the study of a PCL/PVC blend system using FTIR

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Abstract  

In the present paper we describe a technique for the determination of thin layer thicknesses by the conversion electron Mössbauer spectroscopy /CEMS/, using a new alternative method, a parallel plate avalanche counter /PPAC/, operating with the ketone gas in the ionization chamber. We determined the thickness of iron and magnetite on steel.

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The quartz-cristobalite transformation in heated natural chert (flint) rock composed of micro- and ŗypto-quartz was investigated in the temperature interval of 1000–1300°C by micro-Raman spectroscopy, FT-IR spectroscopy, X-ray diffraction and Scanning Electron Microscopy. A small amount of crystobalite was first observed in the chert after heating at 1000°C for 1 h and the transformation was almost completed after heating at 1300°C for 24 h. On the other hand, cristobalite was not detected in well-crystallized pure quartz after heating under the same conditions. The transformation occurs as a solid state nucleation and crystal growth of cristobalite replacing quartz at high-temperatures. The chert rock is naturally rich in crystal defects and boundaries which serve as nucleation sites and enable an earlier quartz-cristobalite transformation.

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The study of a limestone and clay mixture using Mössbauer spectroscopy, and X-ray powder spectrometry (XRD) for different firing temperatures are presented. This type of mixture is used in raw minerals in order to obtain industrial clinker. This study permits to know the changes of the iron present during the clinkerization process, its mineralogical transformation with the temperature, and the minimal temperature necessary to obtain a good quality clinker.

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Abstract  

The dimeric compound [Pd(bzan)(μ-OOCCH3)]2 (1) (bzan=N-benzylideneaniline) reacts with KX, in methanol/acetone (2:1), affording the analogous dimeric pseudohalogen-bridged species [Pd(bzan)(μ-X)]2 [X=NCO(2),SCN(3), CN(4)]. The compounds were characterized by elemental analysis, infrared spectroscopy, NMR and thermogravimetric analysis. IR data for 2–4 showed bands typical of coordinated pseudohalogen ligands clearly indicating the occurrence of the exchange reaction. Their thermal behaviour was investigated and suggested that their stability is influenced by the bridging ligand. The thermal stability decreased in the order[Pd(bzan)(μ-CN)]2>[Pd(bzan)(μ-SCN)]2>[Pd(bzan)(μ-OOCCH3)]2>[Pd(bzan)(μ-NCO)]2. X-ray results showed the formation of Pd as final decomposition product.

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Abstract  

Humic acids (HAs) extracted from soils developed under two Norwegian spruce (Picea abies, (L.) Karst) subalpine forests of northern Italy were characterized using chemical, thermal (TG-DTA) and spectroscopic (DRIFT) analyses. The samples were taken from five sites which differed in orientation (northern and southern exposure) and vegetal cover at different old age: grassland, regeneration, immature and mature stands. In general, the thermal patterns of HAs were similar (three exothermic reactions appeared around at 300, 400 and 500C) in both sites in grasslands and regeneration while a considerable modification appeared in HA from stands of different age at northern and southern exposure site. DRIFT spectroscopy confirmed the differences observed through TG-DTA analysis. In particular the main structural changes were ascribed to modification of carbonyl group and of CH stretching in aliphatic components in each HAs from different sites.

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Abstract  

Thermally stimulated luminescence (TSL), electron paramagnetic resonance (EPR) and photo-acoustic spectroscopy (PAS) techniques were used to investigate the radiation induced centers in polycrystalline LaBa2F7 containing trace amounts of other rare-earths particularly Gd3+ and Sm3+. The TSL glow curve of LaBa2F7 after g-irradiation to a dose of 3 kGy had shown a weak TSL glow peak at 390 K and a much stronger one at 495 K. The EPR spectra of the g-irradiated LaBa2F7 samples showed the presence of O- and O2 - ions. Temperature dependence study of the EPR spectra showed that the thermal destruction of O- ion occurs in the 460-490 K temperature range. In g-irradiated samples, O- and F-centers were identified by PAS. The correlation of EPR and PAS results indicate that the prominent TSL glow at 495 K is associated with the thermal destruction of O- radical ion. The trap parameters viz. trap depth and frequency factor have been determined from TSL data.

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