A high-performance liquid chromatography procedure or the determination of the herbicides simazine, propazine, bromacil, metoxuron, and hexazinone is elaborated. Stationary phases RP8 and RP18 and mixtures of methanol-water (2:1 and 1:1, v/v) as a mobile phase are applied for this purpose. The conditions for solid-phase extraction are established, allowing the separation of phenols and herbicid...

A rapid and reliable capillary zone electrophoresis method was used as a tool to obtain both qualitative and quantitative information about simple phenols, lignans, complex phenols (isomeric forms of secoiridoids), phenolic acids, and flavonoids in the solid-phase separation extracts from different Spanish extra-virgin olive oil in a short time (less than 6 min). Peak identification was done by...

The accurate O-H bond dissociation enthalpies for a series of meta and para substituted phenols (X-C6H4-OH, X=H, F, Cl, CH3, OCH3, OH, NH2, CF3, CN, and NO2) have been calculated by using the (RO)B3LYP procedure with 6-311G(d,p) and 6311++G(2df,2p) basis sets. The proton affinities of the corresponding phenoxide ions (XC6H4-O) have also been computed at the same level of theory. The effect of c...

A simple, fast, sensitive and versatile method for the analysis of phenols in water is proposed using microfluidic precolumn derivatization with the fluorogenic label coumarin-6-sulfonyl chloride (C6SCl) and HPLC separation on monolithic columns. Phenols react with C6SCl within 3.0 min in the microreactor at ambient temperature to produce phenol-coumarin sulphonamides derivatives which were sep...

An on-line post-column reactor based on air-segmented continuous flow is described for the determination of phenols. The reaction used is the coupling of diazotized sulfanilic acid with phenols to form highly colored azo dyes. The effect of experimental parameters on the detector response was investigated by both univariate and simplex approaches in order to establish optimum reaction condition...

Suimnwijitiry. The potential role of indoleactic acid (IAA)-oxidase as an in vivo abscission regullating system in the cotton (Gossvpiutiii hirsttuni L.) cotyledonary explant was investigated. Phenols (utsutally monophenols), which are cofactors of cotton IAA-oxidase in vitro, accelerated abscission. Phenols (tustually orthodihydroxyphenols), which inhibit cotton IAA-oxidase in vitro, inhibited...

The removal of phenol (Ph) and 2-chlorophenol (2-CPh) from aqueous solution by native and heat inactivated fungus Funalia trogii pellets were investigated. The effects of contact time, solid/liquid ratio, optimum pH and temperature on the phenols removal capacity by the pellets were established. The removal efficiency of phenols increased significantly with increasing biomass dose. The optimum ...

The antioxidant activity, total phenols content and phytochemical constituents of edible portions of four underutilised tropical fruits; Irvingia gabonensis (African mango), Artocarpus altilis (breadfruit), Annona muricata (soursop) and Annona squamosa (sweetsop) were determined. Extracts of fruit samples were screened for selected phytochemicals using standard methods whereas the total phenols...