JBCS

Graphical abstract illustrating the conversion of IR spectra of ink samples to a scores plot by making use of the error covariance matrix and maximum likelihood principal components analysis.

PABA-MCM-41 synthesis procedure. Anew functionalized MCM-41-based mesoporous material was synthesized using a hydrothermal/co-condensation method. The CTAB surfactant was removed by refluxing in a solution of CH₃CH₂OH/HCl.

Some physico-chemical parameters and dissolved organic carbon data of waters of a mining region in southeast of Brazil were analysed using the multivariate technique Kohonen neural network. It provided a better visualisation and easier interpretation of the results.

This study developed gluten-free cookies containing the whole flour of quinoa and linseed as source of essential fatty acids and minerals. The Principal Component Analysis (PCA) is a useful chemometric tool to facilitate the visualization of the best formulation.

A DLLME-SFOD method based on the formation of the yellow Se(IV) complex with the 3,3'-diaminobenzidine (DAB) ligand combined with the spectrophotometry method was developed for the preconcentration, separation and determination of the inorganic selenium species.

The steroids composition is not the same for different oils. Free steroids were extracted from unsaponifiable oil using the saponification reaction adapted micro-scale, and after extraction steroids were analyzed by gas chromatography (GC) for separation, characterization and quantification of the steroids contained in this fraction.

[C₄MIM][PF₆] was used as an extracting solvent for pre-concentration of cadmium ions from aqueous solution by temperature controlled ionic liquid dispersive-liquid phase microextraction.

We have developed an efficient method for esterification and thioesterification of various carboxylic acids with different alcohols and thiols using PPh₃/N-chlorobenzotriazole mixed reagent in CH₂Cl₂ at room temperature.

This paper describes a procedure to evaluate metals associated to proteins in wheat seed samples using a sequential extraction procedure.

The occurrence of residues of pharmaceuticals in aquatic environments is considered an emerging environmental issue. In Malaysia, this is the first report to identify these compounds in the Tangkas River. Six pharmaceutically active compounds were detected using LC-ESI-TOF/MS instrument.

NMR experiments at lower temperatures and DFT(B3LYP/6-31G)/PCM methods were used to determine the 3D geometry of the favoured conformer of the macrocyclic ellagitannin oenothein B.

Linalyl acetate (LA): a chemical compound extracted from biomass and used as green corrosion inhibitor. Adsorbed species formed from LA adsorption on the metal surface inhibits the mechanism associated with the oxidation processes of the metal.

Linear alkylbenzene sulphonates (LAS) occur in high concentration in raw sewage, thereof interfering with the analysis of micropollutants by mass spectromety. This paper proposes a tandem solid phase extraction procedure that combines two distinct solid phase extraction cartridges to reduce LAS concentration in the extracts, thereby enhancing the sensitivity of the analytical method for the quantification of five pharmaceutical compounds and three endocrine disrupting chemicals in samples of raw and treated sewage.

A donor-active solvent-assisted liquid-phase microextraction procedure followed by spectrophotometric determination of zinc was developed. The method is based on the ion associate formation between Zn(II), thiocyanate and 2-[2-(5-dimethylamino-thiophen-2-yl)-vinyl]-1,3,3-trimethyl-3H-indolium bromide (DTVTI) reagent which is extractable by the mixture of toluene and tributylphosphate.

Polymer-clayfilms based on cassava starch and synthetic Laponite were prepared. Exfoliated nanocomposites are producedat low clay loadings. Starch crystallinitydecreases as the amount of Laponite is increased. Thermal decomposition profile is sensitive to the clay quantity in the hybrid material.

A simple and fast solid phase extraction sample preparation procedure for the flame atomic absorption spectrometry determination of traces of Cd, Co, Ni and Pb in honeys was proposed. The method provided the precision and the accuracy better than 4.5% and detection limits of 0.005 µg g^-1 (Cd), 0.015 µg g^-1 (Co, Ni) and 0.073 µg g^-1 (Pb)

In this work, the CH₃Cl + OH^- → CH₃OH + Cl^- reaction is investigated at the MP2/6-31+G(d) level and by the CVTST method. Final results for rate coefficients (1.94 x 10^-9 cm³ molecule^-1 s^-1 at 298.15K) are found in agreement with the experimental data.

First Brazilian development of toxic polyaromatic compounds (PAHs) certified reference material, with quality assurance, reliability and traceability for environmental analysis.

In this research, the application of dibromo dimethylhydantoin (DBDMH) and dichloro dimethylhydantoin (DCDMH) in oxidation of secondary alcohols under solvent free condition in the range of temperature 70-80 ºC has been investigated. This method offers some of the advantages as following: simplicity of the reaction conditions and work-up, short reaction times and high yields.

Herein, we report the synthesis of new substituted 3-(2-chloroquinolin-3-yl)-5-phenylisoxazole derivatives by click chemistry on good to moderate yields.

When carbon steel was subjected to constant plastic deformation in a cement extract solution, the thickness of the space charge layers significantly decreased as the deformation magnitude increased.

The Port of Itaqui (São Luís, Maranhão State, Northeast Brazil) stands out for heavy flow of vessels. Irgarol and Diuron are booster biocides present in antifouling paints and they were identified in such region that, jointly with north of Pará State, is located in the largest continuous mangrove area worldwide.