Expensive and complex methodologies are available to determine the ethanol concentration in alcohol gel samples. The aim of this article was to demonstrate that alcoholmeter could be used as an alternative method to determine ethanol in gel formulations. Alcohol gel samples were produced using: hydroxypropylmethylcellulose (HPMC), hydroxyethylcellulose (HEC) and Carbopol 940© (CBP). A factorial design was performed to evaluate the interaction between the ethanol concentration, glycerin and polymer contents in the samples in the recovery data of the ethanol content. Rheological analyses were also performed to identify the limiting factors to ethanol quantification. All the results were compared to high resolution magic angle spinning nuclear magnetic resonance (HR-MAS NMR) as a reference methodology. The results demonstrated that the alcoholmeter could be used to determine alcohol concentration, moreover the level of polymer HEC or HPMC, glycerin and ethanol has no effect in the determination. Yield stress, and not viscosity or flow index, appeared as the limiting factor to the use of alcoholmeter in non-acidified CBP samples. Acidification appears to be mandatory to determination of ethanol concentration in CBP samples. It was possible to achieve an inexpensive, handy and fast methodology to quantify alcohol in gelled samples, in the range of concentrations used in this article.

Parabens are widely used as preservatives in the last decades. Others preservatives such as 2-phenoxyethanol, which in addition to his good antimicrobial activity, has low allergenic potential as well others properties of interest to the cosmetic industry. In this work was developed a method for determination of methylparaben (MP), propylparaben (PP) and 2-phenoxyethanol (FE) in cosmetic products by HPLC-DAD using QuEChERS as sample preparation. For application in cosmetic samples, the original QuEChERS method was modified and optimized by evaluate of different solvents for extraction and sorbents for clean up step. Increases at recoveries of analytes were obtained employing acetone as solvent and PSA for clean up step, showed recoveries between 83.7% and 88.6% for all analytes. The method was validated according to ANVISA (linear range: 0.1 to 2.5 µg mL-1 for MP and PP, and 1.5 to 6.0 µg mL-1 for FE). Precision was evaluated by repeatability and intermediate precision with coefficients of variation (%) lower than 10% in all concentrations analysed, and accuracy was evaluated, with values ranging from 93.77% to 108.13%. The QuEChERS-HPLC-DAD method was tested in real samples (moisturizing cream and lotion, cleansing gel), where the concentration values were found below the maximum limit established by ANVISA.

A binary solvent dispersive liquid-liquid microextraction (BS-DLLME) technique was developed for simultaneous determination of diuron, teflubenzuron, atrazine, and two of its metabolites (desisopropylatrazine and desethylatrazine) in natural waters. The extraction was investigated using a three components mixture design to determine the best ratio between the extractors (dichloromethane and chloroform) and the disperser solvent (acetonitrile). According to the analysis of variance, empirical response surfaces were obtained for each analyte, correlating the absolute recovery and the mixture composition. The analysis of the overlapping surfaces allowed the detection of the best condition for the analytes extraction: 481 µL of chloroform, 56.6 µL of dichloromethane, 906 µL of acetonitrile, 5.00 mL of the aqueous sample, and 10% (m/v) of sodium chloride. The proposed method was validated and successfully applied in the analysis of surface waters, presenting suitable linearity (r > 0.9990), low limits of detection (0.015 to 0.36 µg L-1) and quantification (0.049 to 1.2 µg L-1), and relative recoveries between 84.8 and 106.1%.

This work evaluated the photocatalytic activity of suspended TiO2, and TiO2-coated glass Raschig rings with respect to degradation of estrogens estrone (E1), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2) in aqueous solutions and wastewater effluent samples. Gas chromatography/tandem mass spectrometry (GC-MS/MS) studies were carried out to identify degradation products for EE2. TiO2 suspensions allowed degradation rates higher than 90% for all studied estrogens in 30 min for an artificial (ultraviolet A) UVA-assisted process and aqueous solution. Immobilized TiO2 showed less favorable degradation kinetics, requiring ca. 60 min to achieve almost complete estrogen degradation. Some derivatized degradation products were identified for the first time by GC-MS/MS applying ultraviolet C (UVC) photolysis and TiO2/UVA photocatalysis. A degradation route was suggested for EE2 in UVC photolysis and TiO2/UVA processes. In the degradation of pretreated sewage samples, the immobilized TiO2 was more efficient than free TiO2, allowing ca. 85% removal of E2 and EE2 in 60 min.

A sensitive high-performance liquid chromatography-fluorescence detection method (HPLC-FLD) was developed and validated for 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) determination in wastewater samples. Sample preparation was performed by solid-phase extraction (SPE) on Hypersep C18 cartridges. Conditioning and elution solvents and sample volume were investigated by a 23 factorial design for both analytes. The pre-concentration factor was 2500 times, allowing to quantify 5.0 ng L-1 for both hormones. The SPE-HPLC-FLD method was successfully applied to detect and quantify trace amount of target compounds in raw and treated wastewater samples. E2 was found below limit of quantification in influent and effluent samples. Nevertheless, the recoveries of E2 in standard addition experiments were between 41 and 72%, with relative standard deviations between 4 and 16%. An important matrix effect was observed in the determination of EE2, with fluorescence signal suppression.

Two simple and efficient procedures have been developed for the rapid simultaneous determination of compounds with mutual spectral interference (rifampicin (RIF) and isoniazid (INH)). The first method was based on the UV–Vis spectral signal (190–600 nm) of synthetic RIF and INH aqueous solutions, whereas the second method involved the visible spectral signal registered between 350 and 800 nm after the reaction of INH with a Cu2+/neocuproine complex. Both multivariate spectrophotometric methods show excellent prevision capacity, providing results that are statistically equivalent with those provided by the standard chromatographic procedure. The methods were validated according to criteria established by ANVISA, showing precision, accuracy and robustness compatible with the requirements for new analytical methods, additionally allowing the reduction of waste generation.

O sucesso no tratamento do câncer está intrinsicamente relacionado à sua prévia detecção, até mesmo antes dos sintomas surgirem. Neste contexto, estratégias metabonômicas baseadas na espectroscopia de ressonância magnética nuclear de ¹H (¹H NMR) foram empregadas para identificar as alterações metabólicas ocorridas na composição química de biofluidos de camundongos como consequência do surgimento de tumores. Através da análise discriminante por mínimos quadrados parciais (PLS-DA) dos espectros de ¹H NMR foi possível diagnosticar a presença dos tumores de Ehrlich e Sarcoma 180 após cinco e dez dias da indução dos tumores, respectivamente. Lipídeos, lipoproteínas e lactato foram os biomarcadores mais importantes indicativos do processo carcinogênico. Portanto, estratégias metabonômicas baseadas na espectroscopia de NMR podem ser valiosas ferramentas para investigar os efeitos do surgimento de anomalias celulares na composição química dos biofluidos.

The success of cancer treatment is directly related to early detection before symptoms emerge, although nowadays few cancers can be detected early. In this sense, ¹H nuclear magnetic resonance (¹H NMR)-based metabonomics was used to identify metabolic changes in biofluid as a consequence of tumours growing in mice. Through partial least squares discriminant analysis (PLS-DA) analysis of ¹H NMR spectra from serum samples it was possible to diagnose Ehrlich ascites and Sarcoma 180 tumours five and ten days after cell inoculation, respectively. Lipids, lipoproteins and lactate were the main biomarkers at onset as well as in the progress of carcinogenic process. Thus, NMR-based metabonomics can be a valuable tool to study the effects of tumour establishment on the chemical composition of biofluids.

A estabilidade dos óleos vegetais à oxidação depende do equilíbrio entre a composição e a presença de pró-oxidantes e antioxidantes. O objetivo deste estudo consistiu em avaliar o efeito da presença de antioxidantes sintéticos durante o processo de foto-oxidação dos óleos de canola e milho. As amostras dos óleos de canola e milho em presença e em ausência dos antioxidantes butil-hidroxitolueno (BHA), propil galato (PG) e terc butil-hidroquinona (TBHQ), foram submetidas ao estresse foto-oxidativo. A reação de foto-oxidação seguiu uma cinética de primeira ordem. A constante de velocidade no período de 20 dias de foto-oxidação evidenciou que o antioxidante PG apresentou maior efeito protetor para o óleo de canola e o TBHQ para o óleo de milho. A partir dos dados de UV e RMN de ¹H, no período de 60 dias, constatou-se que os três antioxidantes apresentaram um efeito protetor a foto-oxidação. Os dados de UV evidenciaram aumento de absorção da banda em 232 nm devido à foto-oxidação e formação de dienos conjugados. A redução da intensidade de absorção desta banda na foto-oxidação com o tempo de exposição revelou que a proteção, tanto para o óleo de canola como para o de milho, foi mais efetiva com o antioxidante PG. Os índices de oxidação Roa e fração residual de hidrogênios (H) dialílicos, alílicos e vinílicos também evidenciaram que o antioxidante PG apresentou o melhor desempenho na proteção dos dois tipos de óleo.

The stability of vegetable oils in relation to oxidation depends on the balance between the composition and the presence of antioxidants and pro-oxidants. The objective of this study was to evaluate the effect of the presence of antioxidants in vegetable oils in the protection of photo-oxidation. Samples of canola oil and corn oil in the presence and absence of the antioxidants, butylated hydroxytoluene (BHA), propyl gallate (PG) and tert-butylhydroquinone (TBHQ), were subjected to photo-oxidative stress at room temperature for 60 days. The photo-oxidation reaction followed a first order kinetics. The rate constant for the period of 20 days of photo-oxidation showed that the PG antioxidant showed greater protective effect for canola oil and TBHQ showed a greater protective effect for corn oil. The UV and ¹H NMR data at 60 days showed that the three antioxidants had a protective effect on photo-oxidation. The UV data showed increased absorption at the 232nm band due to photo-oxidation and the formation of conjugated dienes. The reduction in intensity of this absorption band in photo-oxidation with time of exposure revealed that the protection, both for the canola oil and for the corn oil, was more effective with the PG antioxidant. The rates of Roa oxidation and residual fraction of diallyl, allyl and vinyl hydrogens also showed that the PG antioxidant showed the best performance in protecting both oils.

O método de regressão por mínimos quadrados parciais (PLSR) foi utilizado para a quantificação simultânea de dois tuberculostáticos rifampicina (RIF) e isoniazida (INH) por espectrofotometria na região do visível utilizando uma reação de derivatização simples. Na presença de neocuproína, íons cobre(II) foram facilmente reduzidos por INH para um complexo Cu(I)-neocuproína de absorção máxima a 455 nm. Sob essas mesmas condições, RIF mostrou uma absorção máxima a 449 nm. O conjunto de calibração foi estabelecido entre 8 e 57 mg L-1 de RIF e 1,5 e 7 mg L-1 de INH. O método foi aplicado para a determinação das drogas em amostras de urina (recuperações entre 92 e 119%) e em formulações farmacêuticas (erro relativo inferior a 5%).

Partial least squares regression (PLSR) was used for the simultaneous quantification of rifampicin (RIF)and isoniazid (INH) by visible spectrophotometry using a simple derivatization reaction. In the presence of neocuproine, copper(II) is easily reduced by INH to a Cu(I)-neocuproine complex that shows an absorption maximum at 455 nm. Under these conditions, RIF shows an absorption maximum at 449 nm. The calibration set was established between 8and 57 mg L-1 for RIFand 1.5and 7 mg L-1 for INH. The method was applied to the determination of the drugs in urine samples (recoveries between 92and 119%)and in pharmaceutical formulations (relative error lower than 5%).

O estudo da variabilidade espacial de atributos do solo e plantas ou agricultura de precisão, técnica que visa ao uso racional dos recursos naturais, está expandindo-se comercialmente no Brasil. Porém ainda ressente-se de análise que dê respaldo matemático a correlação de variáveis independentes e suas interações com a variável produtividade, identificando padrões científicos tecnologicamente aplicáveis. Objetivou-se identificar padrões de variabilidade do solo com base em onze indicadores químicos e sete físicos em área agrícola. Utilizaram-se duas técnicas de estatística multivariada: análise hierárquica de agrupamentos (HCA) e análise por componentes principais (PCA). De acordo com a HCA, separou-se a área de estudo em cinco zonas de manejo, sendo a zona 1 com 2,87 ha; a zona 2 com 0,8 ha; a zona 3 com 1,84 ha; a zona 4 com 1,33 ha; e a zona 5 com 2,76ha. Por meio da PCA identificaram-se as variáveis mais importantes dentro de cada zona: na zona 1 o V%; na 2 a CTC; na 4 o H+Al, e na 5 o conteúdo de areia e a altitude. A zona 3 foi classificada como uma zona intermediária, apresentando características de todas as outras. Sendo assim, é possível separar em grupos (zonas de manejo) as amostras que possuem os mesmos padrões de variabilidade com técnicas de estatística multivariada.

The study of spatial variability of soil and plants attributes, or precision agriculture, a technique that aims the rational use of natural resources, is expanding commercially in Brazil. Nevertheless, there is a lack of mathematical analysis that supports the correlation of these independent variables and their interactions with the productivity, identifying scientific standards technologically applicable. The aim of this study was to identify patterns of soil variability according to the eleven physical and seven chemical indicators in an agricultural area. It was used two multivariate techniques: the hierarchical cluster analysis (HCA) and the principal component analysis (PCA). According to the HCA, the area was divided into five management zones: zone 1 with 2.87ha, zone 2 with 0.8ha, zone 3 with 1.84ha, zone 4 with 1.33ha and zone 5 with 2.76ha. By the PCA, it was identified the most important variables within each zone: V% for the zone 1, CTC in the zone 2, levels of H+Al in the zone 4 and sand content and altitude in the zone 5. The zone 3 was classified as an intermediate zone with characteristics of all others. According to the results it is concluded that it is possible to separate into groups (management zones) samples with the same patterns of variability by the multivariate statistical techniques.

A composição dos voláteis emitidos por diferentes árvores é usada com sucesso como marcador em uma grande variedade de estudos, como a quimiotaxonomia. A caracterização dos voláteis emitidos por diferentes espécies de Pinus provou ser uma ferramenta importante para entender o processo de seleção de plantas hospedeiras por insetos herbívoros. Os voláteis dos galhos de cinco espécies de Pinus (P. caribaea, P. elliottii, P. maximinoi, P. patula e P. taeda) foram coletados por aeração e analisados por cromatografia gasosa com detector de ionização de chama (GC-FID), utilizando colunas de fase não-polar e quiral, e espectrometria de massas (GC-MS) com analisador de quadrupolo. A composição relativa foi usada para análises de componentes principais (PCA) e de agrupamento hierárquico (HCA) para a discriminação das cinco espécies.

The composition of the volatiles emitted by different trees has been successfully used as a marker in a wide variety of studies, such as chemotaxonomy. Characterization of the volatiles emitted by different species of Pinus has proven to be an important tool to understand the process of host-tree selection by herbivorous insects. The volatiles present in samples of the branches of five species of Pinus (P. caribaea, P. elliottii, P. maximinoi, P. patula and P. taeda) were collected by aeration, and the contents analyzed by gas chromatography using a flame ionization detector (GC-FID), applying non-polar and chiral column phases, and mass spectrometry (GC-MS) using a quadrupole mass analyzer. The relative composition of the different volatiles was used to perform a discriminant analysis among the five pine species, by means of cluster (HCA) and principal component (PCA) analyses.

In this work, the materials used in the recovery of estrogens from aqueous matrices by filtration and solid phase extraction were evaluated. The results showed that glass-fiber filters allow a recovery and repeatability compatible with this type of analysis, whereas cellulose esters lead to significant losses of the analytes, mainly due to adsorption processes. On the other hand, the transferring of the sample to the extraction cartridges should be carried out with glass or Teflon tubing, since the adsorption observed with other polymeric materials (eg. silicone, Tygon, polyethylene and PVC) dramatically reduces the recovery and repeatability of the extraction process.

In this work the evaluation of the dissolution profile of captopril-hydrochlorothiazide and zidovudine-lamivudine associations were carried out by multivariate spectroscopic method. The models were developed by partial least square regression from 20 synthetic mixtures using mean-centered spectral data. The external validation was accomplished with 5 synthetic mixtures shown mean prevision error of about 1%. Good agreement was observed in the analyses of commercial drugs (content uniformity and dissolution profile), considering the results obtained by the standard chromatographic method, with prevision error lower than 10%.

A determinação espectroscópica multivariada da associação lamivudina-zidovudina foi realizada por regressão de mínimos quadrados parciais. O modelo foi desenvolvido a partir de 20 misturas sintéticas utilizando-se dados espectrais centrados na média adquiridos entre 190 e 350 nm e 3 variáveis latentes. A validação externa foi realizada a partir de 6 misturas sintéticas, observando-se erros médios de previsão de aproximadamente 1%. Na análise de medicamentos foram obtidos bons resultados, com erros de previsão inferiores a 10%. A metodologia multivariada foi validada de acordo com os critérios do International Conference on Harmonization (ICH), demonstrando precisão, exatidão e robustez compatíveis com a legislação vigente.

The multivariate spectroscopic determination of lamivudine-zidovudine associations was carried out by partial least square regression (PLS). This model was developed from 20 synthetic mixtures using mean-centered spectral data acquired from 190 to 350 nm and with 3 latent variables. External validation was performed with 6 synthetic mixtures providing prediction errors close to 1%. Moreover, the analysis of commercial drugs showed good results with prediction errors lower than 10%. The multivariate methodology was validated according to International Conference on Harmonization (ICH) criteria, demonstrating precision, accuracy and robustness within legal requirements.

A multivariate spectrophotometric method was developed for analysis of kojic acid/hydroquinone associations in skin whitening cosmetics. The method is based on the reaction between kojic acid and Fe3+ and on the reduction of Fe3+ by hydroquinone and further complexation of Fe2+ with 1,10-phenanthroline. The multivariate model was developed by Partial Least Squares Regression (PLSR), using 25 synthetic mixtures and mean-centered spectral data (350-380 nm). The use of 3 (kojic acid) and 2 (hydroquinone) latent variables permits the observation of mean errors of about 5% in the external validation phase.