JBCS

High-performance liquid chromatography with UV diode array detector (HPLC-UV-DAD) provides quantitative information for planning more detailed analysis. Coffea arabica leaves exposed to sun have higher caffeine contents than shaded ones. Coffea arabica leaves suffer more ecological stress exposed to sun than in shade. Light conditions have very different effects on Coffea arabica and yerba mate leaves. Lipid contents are higher in shaded leaves than those exposed to the sun.

Copolymers of aniline with 2-substituted anilines bearing a variety of carboxyl groups were synthesized and characterized by several techniques. Some of the synthesized copolymers show moderate-to-high solubility in a diverse set of solvents and good-to-excellent conductivity.

Chromatographic retention parameter of the investigated N-substituted-2-phenylacetamide derivatives obtained by reversed phase thin-layer chromatography (RP-TLC) could be used for the description of their lipophilicity and the chemometric methods used are able to reduce the dimensionality of the data and create a connection between large numbers of data obtained in different ways.

The total phenolic contents, total flavonoid contents, total ketosteroid contents, antioxidant activities, and phenolic composition of cornhusk, corncob, and stigma maydis were evaluated.

1-Methylcarbazole-2,3-dicarboxylic acid dimethyl ester, a key intermediate in the synthesis of b-fused carbazoles can be selectively brominated or nitrated at position 6. Subsequent annulation of a pyridazine or pyrrole ring with basic side chains gives new compounds with cytotoxic activity against human tumor cells.

A solid phase extraction method using cadion immobilized on sodium dodecyl sulfate-coated TiO₂ nanoparticles combined with cold vapor atomic absorption spectrometry has been proposed for the separation, preconcentration and determination of cadmium.

The response surface demonstrates that mixtures containing the antioxidants tert-butylhydroquinone (TBHQ) and propylgallate (PG) provide activation energy (E_a, for biodiesel oxidation reaction) greater than 160 kJ mol^-1.

Bioaccessibility of Ca, Mg, Mn and Fe in ground coffee brews was assessed using in vitro gastrointestinal digestion. Among studied metals, Mg was the most bioaccessible (62%). The bioaccessibilities of Ca (42%) and Fe (43%) were similar but individual results for both metals varied widely. The least bioaccessible metal was Mn.

The central composite design done for simultaneous degradation of diuron (DR) and hexazinone (HX) via H₂O₂/UV showed that the H₂O₂ concentration is more influential than pH. The optimum degradation conditions provided a total organic carbon removing of 96.4% and the reduction in toxicity.

The photodegradation of chloramphenicol (CAP) in different aqueous media using solar and artificial irradiation was evaluated, being determined the reaction kinetics and initial transformation products.

The extraction of analytes by single drop microextraction (SDME) is not exaustive and the amount extracted is dependent on the contact time. Migration of analytes (pesticides) of the aqueous phase to the organic phase followed by diffusion kinetics model Noyes-Whitney.

Catalytic oxidation of benzene, toluene and xylene (BTX), to CO₂ and H₂O promoted by WO₃ catalyst.

A simple, rapid, inexpensive, direct and green FTIR methods for the analysis of two antidiabetic drugs. Such methods have a strong potential to replace classical methods in quality assurance/quality control (QA/QC) in pharmaceutical preparations.

A new magnetic iron oxide nanoparticle for extraction and determination of lead and copper ions from water samples was synthesized and characterized with different techniques. This adsorbent has not been used before for the separation and preconcentration of trace amount of metal ions.

Aniline and pyrrole monomers were added onto a filter paper, and then oxidant was added to the mixture. During the polymerization of aniline and pyrrole, they penetrated into the cellulose structure of the filter paper and it changed to a black color. Thus, a nanocomposite of PANI/PPY-cellulose was made and used as a solid phase extraction sorbent.

A new mixed oxide (SiO₂/TiO₂/ZnO)-based sorbent was evaluated for copper preconcentration and determination in water and food samples. The sorbent presents high reusability and proposed preconcentration method shows satisfactory sample consumption and limit of detection.

SPE-FAAS system was used for preconcentration and determination of Pb(II) and Cd(II) ions by synthesized graphene oxide and 4-acetamidothiophenol as adsorbent and chelating reagent, respectively.

Diaquabis(L-phenylalaninato)nickel, when encapsulated in zeolite, exhibited high catalytic activity and selectivity when cyclohexene, ethyl benzene and toluene were oxidized by hydrogen peroxide.

Novel Eu³⁺-indandionate complexes containing 1,10-phenanthroline and 4,7-dimethyl-1,10-phenanthroline as neutral ligands have been reported. The luminescent and structural properties of these compounds have been investigated using experimental and theoretical methods.

Sugarcane bagasse was pretreated with three novel chemically inert 1,2,3-triazolium-based ILs and the effect of pretreatment on lignocellulosic biomass showed that the pretreatment promoted structural changes in the fiber increasing the surface exposure of the bagasse samples.

LC-MS and LC-PDA were employed to appraise the intrinsic stability of donepezil. The drug and their degradation products were separated and detected after forced degradation studies.

The decomposition of three phenolic acid compounds (salvianic acid A, protocatechuic acid and ferulaic acid) increased with rising temperature and the acids became less stable with longer heating time. Reaction temperature and time showed relatively little effect on the decomposition of catechol and protocatechualdehyde.

An unknown compound, in addition to seven known alkaloids and three glycosides from the ethanol extract of seeds of Aspidosperma pyrifolium are reported. The nuclear magnetic resonance data assignments of several alkaloids reported in the literature are suggested to be revised, and the antinociceptive and anti-inflammatory activities are presented.

Phytochemical investigation of the leaf extracts of Clinopodium tomentosum (Lamiaceae) allowed the isolation of one new tartaric acid derivative, together with twelve known compounds.

Palladium- and copper-catalyzed highly selective mono-coupling between 2,6-diiodoanisoles and terminal alkynes has provided alkynylated 2-iodoanisoles as useful building blocks with potential application in the synthesis of functionalized benzo[b]furans.