Analysis of nitrophenols in cloud water with a miniaturized light-phase rotary perforator and HPLC-MS

An all-glass miniaturized light-phase rotary perforator for the enrichment of polar compounds has been modified/miniaturized and applied. Its application is demonstrated here for the analysis of nitrophenols and dinitrophenols from low-concentration/low-volume samples. For the method development of high-performance liquid chromatography–mass spectrometry (MS) four eluents were tested: (1) water–methanol, (2) acetic acid–methanol, (3) trifluoroacetic acid–methanol and (4) water–acetonitrile. The last eluent mentioned was used for the subsequent investigation of samples from field experiments. Detection limits varied between 1 ng and 50 pg. The relative standard deviation in repeated measurements was below 15%, corresponding to a good reproducibility. Recoveries ranged between 31 and 100%, showing a significant dependence on the extraction time and the final volume of the sample after evaporation. Quantification was carried out by using deuterated 4-nitrophenol and 2,4-dinitrophenol as standards and applying previously determined response factors. Structure determination of further substances under atmospheric pressure chemical ionization was performed by a first screening with a source collision-induced dissociation, followed by the definite analysis by MS ⁿ . The first results are shown for cloud water, fog water and rainwater samples from different locations.     

Solar Light Induced Photocatalytic Degradation of Pollutants over Titania Pillared Zirconium Phosphate and Titanium Phosphate

Titania pillared zirconium phosphate (ZrP) and titanium phosphate (TiP) were prepared by intercalating Ti (IV) isopropoxide sol in the interlayers of the mono sodium form of the corresponding metal phosphate. The sol-intercalated samples were activated at various temperatures and characterized by XRD, UV–vis DRS, FTIR, BET-surface area, BJH-pore size distribution and acid sites measurement. Basal spacing and surface area analyses revealed that highest amount of pillaring has taken place with 2 and 4 wt.% titania loading for ZrP and TiP, respectively. The photocatalytic degradation of 4-nitrophenol (4-NP), phenol, methylene blue (MB) and hexavalent chromium (Cr (VI)) was studied in aqueous solution over the neat as well as pillared materials under solar irradiation. Catalytic activity tests revealed that hexavalent chromium (Cr (VI)) and 4-nitrophenol (4-NP) were completely degraded under acidic conditions, whereas, the same was observed in almost neutral conditions for phenol and methylene blue (MB) over 0.6 g/L of catalyst.

Phenols in whisky

Summary Twelve volatile phenols were identified in whisky by combined gas chromatography-mass spectrometry. Of these phenols 2,4-dimethylphenol was found for the first time in the aroma of whisky. The content of phenol, o-, m-, and p-cresol, guaiacol, p-ethylphenol, p-ethylguaiacol and eugenol in whiskies originating from different countries was determined by gas chromatography as their 2,4-dinitrophenyl ethers using electron capture detection. The results show that Scotch whiskies differ from others in the content of o-, m-, and p-cresol. The odour threshold values of phenols studied were determined in a 10% (v/v) ethanol-water mixture and in some cases also in the whiskies. Cresols have been found to make contribution to the aroma of Scotch whisky.Presented at the 14th International Symposium on Chromatography London, September, 1982     

Biosensors for phenol derivatives using biochemical signal amplification

Two different approaches, both exploiting two enzymes cooperative functioning, to enhance the sensitivity of tyrosinase (PPO) based biosensor for amperometric detection of phenols have been compared. For this purpose, one monoenzyme electrode (PPO) and two bienzyme electrodes (PPO and d-glucose dehydrogenase, GDH; PPO and horseradish peroxidase, HRP) were constructed using agar-agar gel as enzyme immobilization matrix. The biosensors responses for l-tyrosine detection were recorded at −50 mV versus saturated calomel electrode (SCE). The highest sensitivity (74 mA M⁻¹) was observed for the PPO-GDH couple, while that recorded for PPO-HRP couple system was only 32 times higher than that measured for monoenzyme electrode (0.01 mA M⁻¹). The ability of the PPO-, PPO-GDH-, PPO-HRP-based biosensors to assay phenols was demonstrated by quantitative determination of phenol, 1,2-dihydroxybenzene, 1,3-dihydroxybenzene, 1,4-dihydroxybenzene, 2-amino-3 (4-hydroxyphenyl) propanoic acid, 2-hydroxytoluene, 3-hydroxytoluene, 4-hydroxytoluene, 4-clorophenol, 3-clorophenol, 2-clorophenol, 4-hydroxybenzoic acid.     

Strategies for the determination of bioactive phenols in plants,fruit and vegetables

Analytical strategies dealing with bioactive phenols in plants and foods are reviewed. These depend on the purpose of the analysis which may be classified as studies where the principal purpose is biological screening, phytochemical and/or chemical screening. Nevertheless, extraction of the phenol from the sample matrix is common and methods of achieving a suitable extract are assessed. Advances in the separation sciences and spectrometry are exploited for identification and quantification of isolated phenols. The various procedures are summarized and some typical “case studies” are presented. Two important areas are introduced briefly. Thus, plant phenols are reactive species and their ultimate fate has been relatively neglected. Studies of bioactive compounds generate a considerable volume of data making data handling and informatics important topics that warrant a separate review.     

水中痕量酚的富集和紫外分光光度测定法的研究

本文研究了用微型树脂柱快速富集,分离,紫外分光光度测定水中痕量酚的方法。结果表明,以GDX-502为吸附剂,水样pH为1～3并含0.2mol/L氯化钠,以每分种15～20ml的速度通过吸附柱,以热的1％氢氧化钠水溶液为淋洗剂时,在291nm处测定苯酚的回收率为89～98％。此外探讨了干扰物的消除方法。吸附柱对苯酚的富集倍数达300倍,最低检测限为0.001ppm。方法精密度为0.3(％),相对标准偏差为3.18％。本法对实际水样进行了测定。结果满意。