Microwave-assisted acid hydrolysis of toluene diamine conjugates in urine samples for biomarkers in toluene diisocyanate analysis

Toluene diamines (TDAs) in urine have been used widely to determine the amount of toluene diisocyanate (TDI) absorbed by humans. Conventional hydrolysis to prepare a sample of urine takes approximately 16 h. An attempt is made to apply microwave-assisted heating (MAH) to reduce the duration of analysis. Urine collected from rats exposed to a mixture of 2,4- and 2,6-TDI was diluted with non-exposed human urine 1/1250-, 1/500- and 1/250-fold. The urine samples were hydrolyzed by both conventional heating and MAH. The hydrolysis efficiency obtained using MAH significantly exceeded that obtained using conventional heating. Hydrolysis by MAH required only 20 min, 48 times faster than with conventional heating. The use of the MAH method in hydrolysis was demonstrated to be reproducible, timesaving and efficient technique in measuring the concentration of urinary TDAs.     

Brønsted acid-mediated ring-opening reactions of methylenecyclopropanes: a dramatic counter ion effect

We report herein two different ring-opening patterns of methylenecyclopropanes (MCPs) in the presence of two Brønsted acids heptadecafluorooctane-1-sulfonic acid (C₈F₁₇SO₃H) and toluene p-sulfonic acid (TsOH) under mild conditions: (a) the ring-opening of MCPs by H₂O and subsequent etherification give the corresponding homoallylic ethers in the presence of heptadecafluorooctane-1-sulfonic acid; (b) the direct ring-opening of MCPs by the Brønsted acid gives the corresponding homoallylic alcohol derivatives in the presence of toluene p-sulfonic acid.     

GMA-EDMA-TiO2扩张床介质合成的改进及其在复合干扰素分离纯化中的应用

通过合成条件的改进,得到了一种性能更好的扩张床介质GMA-EDMA-Lipo-TiO2(GELT),其平均密度为1.25g/ml,孔容为0.564ml/g,平均孔径为15.6nm,比表面积为127.58m2/g,渗磨圆球率为95%。研究表明GELT在氢氧化钠溶液是稳定的。同时讨论了甲苯致孔剂对孔结构的影响及二氧化钛添加量对湿真密度的影响;将GELT与二乙胺偶联得到阴离子树脂(GELT-DEAE),在静态和动态条件下,GELT-DEAE吸附量分别88mgBSA/ml、65mgBSA/ml。将GELT-DEAE应用于扩张床直接从发酵液中分离复合干扰素,一步活性收率为75%,后经SPSepharoseFF离子交换层析和CellufastGel01凝胶层析进一步纯化。最后得到的成品其比活为6.82×108IU/mg,与商品干复津(Infergen)的比活相当,纯度为95%。     

Detection of hippuric acid: A glue solvent metabolite,using a mobile test kit

Many testing kits for screening common drugs are widely used in Malaysia, such as the dip strip urine drug testing kit which is specified for detecting drug in abuser. However, currently there is no specific testing kit for screening urine samples to detect glue abusers. This research is dedicated to develop a specific color test method to emphasize the screening for glue abusers, known as G.S. Kit. It contains benzenesulphonyl chloride, pyridine and distilled water. The urine sample is mixed with pyridine and benzenesulphonyl chloride and followed by distilled water. A positive result will be in the form of a color reaction from yellow to red. This novel G.S. Kit would be quite useful for the screening and detection of glue sniffing and toluene abusing qualitatively, as a way of helping National Anti Drug Agency, Department of Education and Royal Police of Malaysia in preventing glue sniffing from becoming a social pandemic.     

Enhanced effect of RM-β-cyclodextrin on biodegradation of toluene in wastewater by activated sludge

Recently, air and ground water pollution and contamination of soil by toluene have been drawing increasing attention and became an urgently important problem in environmental pollution. Hence, the development of highly sophisticated removal techniques of toluene is required for the global environmental preservation. Since toluene is a highly volatile material, it is difficult to treat it by usual activated sludge water treatment. In this study, in order to prevent volatilization of toluene, randomly methylated β-cyclodextrin (RM-β-CD) was used to complex with toluene and by reason of that, facilitates the biodegradation of toluene by activated sludge. The enhanced effect of RM-β-CD for the biodegradation of toluene by activated sludge was studied in batch systems. The addition of RM-β-CD dominantly promoted proliferation of activated sludge. This implied that the addition of RM-β-CD prevented toluene from evaporating during treatment, and as a result, toluene was effectively decomposed by the activated sludge.     

Crystal and Molecular Structure of an Inclusion Complex of p-tert-Butylcalix[6]arene with Toluene

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Correlations between the Rayleigh ratio and the wavelength for toluene and benzene

The values of the Rayleigh ratio of two pure liquid, toluene and benzene, at various wavelengths have been collected from the literature, and a correlation between the Rayleigh ratio and the wavelength in the form of power law has been developed for each liquid and can be used to compute accurately the Rayleigh ratio at any wavelength between 420 and 700 nm. The Rayleigh ratio scales with the wavelength with a power of −4.17 and −4.38, respectively, for toluene and benzene, which deviate significantly from the Rayleigh law (−4.0). However, if the effect of the wavelength on their refractive indexes is accounted for, the power is reduced to −4.0 and −4.2 for toluene and benzene, respectively.     

Phase equilibria on five binary systems containing 1-butanethiol and 3-methylthiophene in hydrocarbons

Isothermal vapor–liquid equilibrium (VLE) of the following systems was measured with a recirculation still: 1-butanethiol + methylcyclopentane at 343.15 K, 1-butanethiol + 2,2,4-trimethylpentane at 368.15 K, 3-methylthiophene + toluene at 383.15 K, 3-methylthiophene + o-xylene at 383.15 K, and 3-methylthiophene + 1,2,4-trimethylbenzene at 383.15 K. 1-Butanethiol + methylcyclopentane and 1-butanethiol + 2,2,4-trimethylpentane systems exhibit positive deviation from Raoult's law, whereas systems containing 3-methylthiophene in aromatic hydrocarbons exhibit only slight positive deviation from Raoult's law. A maximum pressure azeotrope was found in the system 1-butanethiol + 2,2,4-trimethylpentane (x₁ = 0.548, P = 100.65 kPa, T = 368.15 K). The experimental results were correlated with the Wilson model and compared with original UNIFAC and COSMO-SAC predictive models. Raoult's law can be used to describe the behavior of 3-methylthiophene in aromatic hydrocarbons at the experimental conditions in this work. Liquid and vapor-phase composition were determined with gas chromatography. All measured data sets passed the thermodynamic consistency tests applied. The activity coefficients at infinite dilution are also presented.     

Reaction of the heteronuclear cluster RuOs3(μ-H)2(CO)13 with toluene

The heteronuclear cluster RuOs₃(μ-H)₂(CO)₁₃ (4) reacts with refluxing toluene to form the clusters Ru₂Os₃(μ-H)₂(CO)₁₆ (5) RuOs₃(CO)₉(μ-CO)₂(η⁶-C₆H₅Me) (6) and Ru₂Os₃(CO)₁₂(μ-CO)(η⁶-C₆H₅Me) (7). Cluster 5 exists as a mixture of five isomers. The inter-relationship among the clusters has also been investigated.     

Field analysis of benzene, toluene, ethylbenzene and xylene in water by portable gas chromatography-microflame ionization detector combined with headspace solid-phase microextraction

In this work, portable gas chromatography-microflame ionization detection (portable GC-μFID) coupled to headspace solid-phase microextraction (HS-SPME) was developed for the field analysis of benzene, toluene, ethylbenzene and xylene (BTEX) in water samples. The HS-SPME parameters such as fiber coating, extraction times, stirring rate, the ratio of headspace volume to sample volume, and sodium chloride concentration were studied. A 65 μm poly(dimethylsiloxane)-divinylbenzene (PDMS-DVB) SPME fiber, 900 rpm, 3.0 ml of headspace (1.0 ml water sample in 4.0 ml vial), and 35% sodium chloride concentration (w/v) were respectively chosen for the best extraction response. An extraction time of 1.0 min was enough to extract BTEX in water samples. The relative standard deviation (R.S.D.) for the procedure varied from 5.4% to 8.3%. The method detection limits (MDLs) found were lower than 1.5 μg/l, which was enough sensitive to detect the BTEX in water samples. The optimized method was applied to the field analysis of BTEX in wastewater samples. These experiment results show that portable GC-μFID combined with HS-SPME is a rapid, simple and effective tool for field analysis of BTEX in water samples.