Ruminant milk is the lead source of conjugated linoleic acid (CLA) in the human diet, with cis-9, trans-11 CLA being the major among all. Small amounts of trans-10, cis-12 CLA are also found in synthetic supplements. Since both isomers are biologically active with potential health benefits, there is great interest in quantifying them for quality control routines. An alternative method for the analysis of the aforementioned CLAs by fast gas chromatography (GC) is discussed in the present study. The fatty acid methyl ester mixture obtained by alkaline catalysis was injected into a GC equipped with a fame ionization detector (FID) and fitted with an ionic liquid SLB-IL111 chromatographic column (15 m × 0.10 mm × 0.08 µm). Separation was achieved in less than 5 min using a 168 °C isotherm run. Both CLA isomers were quantified by using of single point standard addition statistical approach. Results were contested to those obtained using the recommended 100 m long CP-Sil88 capillary column and none evidence of significant differences was found within 95% confidence interval. Therefore, the proposed method could be valuable to focused regulatory routines of large numbers of samples with greater analytical frequency.

Buffers are a widely used resource to keep solutions from abruptly change their pH when amounts of acids or bases are added or when dilution occurs. Considering this, buffer is a topic addressed in several university majors and due its relevance should be well known by students and by all professionals who eventually need to prepared a buffer. Mistakes during the procedure might bring unwanted effects depending on the purpose of the buffer. Even though the theory behind buffers is extensively covered in textbooks, the calculations required can sometimes be interpreted as difficult. Therefore, the aim of this work is to disseminate a tool to assist on these calculations. We provide a practical guide on how to prepare buffers of the user’s choice with or without ionic strength adjustment. Exploring the free software PeakMaster®, the user can calculate pH, ionic strength, buffer capacity and predict the precise concentration of each component involved to the proper preparation of the most common and several others buffer solutions. In addition, we hope this paper can be helpful for anyone who is interested in acquire deeper knowledge about buffers.

The present work describes a mini oven built to be applied in the preparation of monolithic stationary phase through the thermal polymerization approach. The developed device was successfully tested for functionalization of monolithic stationary phase in the internal surface of the silica capillary column fused with gold nanoparticles.

Resumo Este trabalho descreve a análise de tecidos comestíveis de frango como coração, fígado e moela, crus e cozidos com temperos em diferentes panelas (panela de ferro, panela de alumínio e panela de alumínio batido) comumente utilizadas no Brasil. A digestão ácida assistida por radiação micro-ondas, com utilização de ácido nítrico diluído, foi empregada para decomposição das amostras. Os teores dos elementos metálicos Al, Ca, Cu, Fe, Mn e Ni foram determinados por Espectrometria de Emissão Óptica com Plasma Induzido por Micro-ondas. A comparação dos teores de Fe obtidos também por Espectrometria de Absorção Atômica em Chama mostrou uma boa exatidão do método. Os limites de quantificação para os analitos avaliados ficaram abaixo de 0,011 mg kg-1, mostrando detectabilidade adequada. As cocções das amostras nas diferentes panelas utilizadas promoveram um aumento dos teores de cinzas e proteínas e uma diminuição dos teores de umidade. A Análise de Componentes Principais e os diagramas de caixa mostraram que as variáveis Ca e Fe apresentaram as maiores variações entre as amostras, seguidas pelas variáveis Al e umidade. As variáveis Al, Cu, Mn, Ni, cinzas e proteínas apresentaram comportamento semelhante após a cocção nos três tipos de panela empregados. A amostra de fígado cozida tanto na panela de ferro quanto na panela de alumínio batido apresentou teores similares de Fe, enquanto as amostras de coração e moela apresentaram teores similares de Ca após cocção nas mesmas panelas.

Abstract This work describes the analysis of different chicken tissues (gizzard, heart, and liver) both raw and cooked with seasonings in different types of cooking pots (iron pot, , aluminum pot and hammered aluminum pot) commonly used in Brazil. The samples were decomposed using microwave-assisted digestion with diluted nitric acid; and the contents of Al, Ca, Cu, Fe, Mn and Ni were determined using Microwave Induced Plasma Optical Emission Spectrometry (MIP OES). The Fe content was also determined by Flame Atomic Absorption Spectrometry, and the comparison showed good accuracy of the method. The limits of quantification were below 0.011 mg kg-1, showing adequate detectability. Cooking in the different pots increased the ash and protein contents as well as decreased the moisture content. Box-plot and Principal Components Analysis showed that Ca and Fe contents present the largest variations in the samples, followed by Al and moisture. The variables Al, Cu, Mn, Ni, ash, and protein presented similar behavior after cooking in all different pots. In addition, liver cooked in both iron and hammered aluminum pots presented similar Fe contents, while gizzard and heart showed similar Ca contents.

Abstract This work describes the synthesis of composites steatite/flexible polyurethane by replacing 4.5 wt. % of polyol with steatite rock powder. We evaluated two mechanical properties of composites (comfort factor and support factor) for various formulations based on a fractional factorial design. The new synthesized composites showed higher support factor, greater comfort factor, and lower cost, compared to conventional flexible polyurethane foams. There is not a significant change in the chemical composition of the foams, due to substitution of 4.5 wt. % polyol by steatite. However, there was a decrease in cell size and greater interaction between the hard segments of the composite.

Abstract A 32 factorial design was employed to develop an in vitro digestion method for estimation of Fe bioaccessible fractions in cooked chicken meat. The effects of sample size and the in vitro bioaccessible fractions of this essential element were evaluated. A sample preparation method employing a microwave assisted digestion with dilute nitric acid was used prior to total Fe determination. For the bioacessibility studies, the optimized procedure employed 7.5 g of sample and 6% w/v of an acid pepsin solution. This procedure was applied to two kinds of chicken meat samples: breast and liver. Flame Atomic Absorption Spectrometry was used to determine total and bioaccessible (chyme or soluble portion) levels of iron in the samples. With respect to total Fe content, the bioaccessible fractions of Fe found in these samples were around 23% and 56 %, for breast and chicken liver, respectively. The chicken liver sample showed the highest total (400 ± 10 mg kg-1) and bioaccessible Fe contents (223 ± 18 mg kg-1) and stands out as a good source of this micronutrient.

A fast gas chromatography with a flame ionisation detector (GC-FID) method for the simultaneous analysis of methyl palmitate (C16:0), stearate (C18:0), oleate (C18:1), linoleate (C18:2) and linolenate (C18:3) in biodiesel samples was proposed. The analysis was conducted in a customised ionic-liquid stationary-phase capillary, SLB-IL 111, with a length of 14 m, an internal diameter of 0.10 mm, a film thickness of 0.08 µm and operated isothermally at 160 °C using hydrogen as the carrier gas at a rate of 50 cm s-1 in run time about 3 min. Once methyl myristate (C14:0) is present lower than 0.5% m/m in real samples it was used as an internal standard. The method was successful applied to monitoring basic and acidic catalysis transesterification reactions of vegetable oils such as soybean, canola, corn, sunflower and those used in frying process.

<p>Among the analytical separation techniques, capillary electrophoresis (CE) has attracted attention in both academic and industrial fields, mainly owing to its efficiency, short analysis times, low reagent consumption and residue generation. This is also the case in Chemistry courses, books and papers, demonstrating CE´s well-established status. However, despite the range of available bibliographic material, there is a lack of animations showing the CE dynamic process. Therefore, the aim of this work was to show the development of a group of animations available for public access, where electrolyte and analytes movements under different CE modes; electropherogram formation; and online ultraviolet-visible spectra can be viewed. The normal or reverse electroosmotic flow generation in the vicinity of the silica capillary wall and the partition motion of neutral compounds between micellar and aqueous phases are also shown. Capillary zone electrophoresis, micellar electrokinetic chromatography, capillary electrochromatography, capillary isoelectric focusing, capillary isotachophoresis and capillary gel electrophoresis, are included in this package. This animation approach can be highly didactic and can complement the theoretical study of CE techniques, which may aid researchers, teachers and students interested in understanding the dynamism and potential of different CE modes.</p>

The filling of capillaries via the sol-gel process is growing. Therefore, this technical note focuses on disseminating knowledge acquired in the Group of Analytical Chemistry and Chemometrics over seven years working with monolithic stationary phase preparation in fused silica capillaries. We believe that the detailed information presented in this technical note concerning the construction of an alternative high pressurization device, used to fill capillary columns via the sol-gel process, which has promising potential for applications involving capillary electrochromatography and liquid chromatography in nano scale, may be enlightening and motivating for groups interested in developing research activities within this theme.

In vitro release of bioidentical hormones in four different liposomal transdermal emulsions (containing testosterone, progesterone, estradiol, or estradiol and estriol) was assessed. For this purpose, novel high-performance liquid chromatography methods were developed and validated in an eco-friendly manner and used to determine the in vitro release of such products. The methods were suitable for our intended goal, and the emulsions employed were found to be effective as transporting candidates for the efficient release of hormones in the transdermal delivery of human sexual steroids.

The assembly of a photochemical reactor with six fluorescent lamps, used for photopolymerizations is described. This chamber presents a mobile support, allowing the placement of samples at different heights and a safety lock that interrupts the radiation, if it is opened during operation. The mirrored internal walls avoid the dispersion and non-uniform distribution of light. There is no high heating because the own character of the used lamps. All parts could be purchased in commerce with less than U$ 150,00. This reactor was successfully used for monolithic stationary phase photopolymerization.