Pheromones are essential for colony organization in honeybees. The pheromones 9-ODA ((E)-9-oxodec-2-enoic acid) and 9-HDA ((E)-9-hydroxydec-2-enoic acid), produced by the mandibular gland of the queen, have various functions within the colony, including inhibition of ovarian development of workers, attraction of swarms, and stabilization of the cluster group. An example of reaction of the colony to adverse conditions is absconding, which is defined as mass exit of all of the adult individuals, leaving even brood and food. In this study, the pheromones 9-ODA and 9-HDA were determined in virgin and normal mated, egg-laying European Carniolan and Africanized queens, as well as in mated queens that were in absconding colonies, using liquid chromatography with UV detection developed methodology. Absconding was induced by maintaining free-flying five-standard-Langstroth-frame colonies in a chamber artificially heated to 45 ºC. The obtained results showed that the amount of 9-ODA in Africanized queens (6.56 µg bee-1) is very low compared with European queens. However, large amounts of 9-HDA were found in the queens of absconding Africanized swarms (107.4 µg bee-1). According to our results, the quantities of 9-ODA and 9-HDA in Africanized honeybees in Brazil may be contributing to the high rates of absconding, promoting low effect of stabilizing agent, and high effect of attraction of dispersers cluster.

Parkinson’s disease is a neurodegenerative disorder characterized by progressive loss of dopaminergic neurons. There is substantial evidence that the endocannabinoid system modulates the dopaminergic activity in the basal ganglia, a forebrain system that integrates cortical information to coordinate motor activity regulating signals. In this article, a fused-silica capillary with a molecularly imprinted polymer was developed for in-tube solid-phase microextraction of the endocannabinoid anandamide in plasma samples from Parkinson’s disease patients and further analysis by ultra-high-performance liquid chromatography with tandem mass spectrometry. The molecularly imprinted polymer capillary presented recognition sites with complementary shape, size, and functionality to anandamide. Scanning electron micrographs and Fourier transform infrared spectra illustrated the physical and chemical modification of the printed and non-printed capillary surface. The in-tube solid-phase microextraction ultra-high-performance liquid chromatography with tandem mass spectrometry method presented a linear range from 0.1 to 20 ng mL-1, precision with coefficient of variation values ranging from 1.2 to 13%, and relative standard deviation accuracy ranging from -3.6 to 7.5%. The method developed herein can adequately determine anandamide in plasma samples from Parkinson’s disease patients. By applying the standard addition approach, the anandamide plasmatic concentration in these samples was found to range from 0.2 to 0.4 ng mL-1.

Two molecularly imprinted polymers (MIPs) were synthesized, by sol-gel and radical polymerization procedures. These MIPs were evaluated as selective stationary phases for miniaturized solid phase extraction (MISPE) to determine parabens in plasma samples by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Selective cavities of the MIPs, based on molecular recognition (hydrogen bonds), were revealed after removal of the template (benzylparaben). Both MIPs were characterized by scanning electron microscope (SEM) and Fourier-transform infrared spectroscopy (FTIR). MIP prepared by radical process presented higher selective binding capacity for the target parabens than MIP prepared by sol-gel. Several variables that influence MISPE performance, including sample pH, sorbent washing, elution solvent, and elution solvent volume were also evaluated. According to the analytical validation parameters, the MISPE/UHPLC-MS/MS method is suitable for the analysis of parabens in plasma samples. The effectiveness of this method was demonstrated through the analyses of the umbilical plasma samples from postpartum women.

Duas técnicas analíticas baseadas no equilíbrio de partição, extração sortiva em barra de agitação (SBSE) e microextração por sorvente empacotado (MEPS) foram avaliadas para a determinação de antidepressivos inibidores seletivos da recaptação de serotonina (SSRI): fluoxetina, sertralina, citalopram e paroxetina, em amostra de plasma por eletroforese capilar em meio não aquoso (NACE) com detecção espectrofotométrica. Os métodos SBSE/NACE e MEPS/NACE apresentaram linearidade na faixa de concentração do limite de quantificação (LOQ) até 500 ng mL-1. Os valores de LOQ variaram de 10 a 30 ng mL-1, em ambas as técnicas, dependendo do fármaco. A precisão interensaio dos métodos apresentou coeficiente de variação inferior a 12%. Os resultados analíticos de validação demonstraram que os métodos são adequados para análises de antidepressivos ISRS em níveis terapêuticos e, consequentemente, para fins de monitorização terapêutica. Estes métodos reduziram os volumes de amostras biológicas, a utilização de solventes orgânicos e o número de etapas do preparo das amostras.

Two approaches based on partition equilibrium, stir bar sorptive extraction (SBSE) and microextraction by packed sorbent (MEPS) were evaluated for determination of selective serotonin reuptake inhibitor antidepressants (SSRI): fluoxetine, sertraline, citalopram and paroxetine in plasma sample by non-aqueous capillary electrophoresis (NACE) with spectrophotometric detection. The SBSE/NACE and MEPS/NACE methods showed linear range from the LOQ up to 500 ng mL-1. LOQ values ranged from 10 to 30 ng mL(-1)1 in both techniques, depending on the compound. The inter-assay precision of the methods presented coefficient of variation lower than 12%. According to the analytical validation results, the methods are adequate for SSRI antidepressant analyses at therapeutic levels, consequently, amenable to therapeutic drug monitoring. These methods reduced the volumes of biological samples, the use of organic solvents and the number of steps involved in sample preparation.

A fase extratora de politiofeno (PTh), desenvolvida por eletropolimerização em haste de aço inox, foi avaliada para microextração em fase sólida (SPME) e análise por cromatografia líquida com detecção espectrofotométrica (LC-UV) de antidepressivos inibidores seletivos da recaptação de serotonina (citalopram, paroxetina, fluoxetina e sertralina) em amostras de plasma. A influência das variáveis da eletropolimerização (velocidade de varredura de potencial, potencial e ciclos de varredura) foi avaliada no desempenho SPME. As variáveis SPME (tempo de extração, temperatura, pH da matriz, força iônica e procedimento de dessorção), assim como a influência das proteínas do plasma no mecanismo de sorção, foram também avaliadas. O método SPME-PTh/LC-UV desenvolvido para a determinação de antidepressivos em amostras de plasma apresentou faixa linear de resposta do limite de quantificação (LOQ, 200-250 ng mL-1) a 4000 ng mL-1 e precisão interensaio com coeficiente de variação no intervalo de 11 a 15%. O método proposto poderá ser utilizado para a determinação de antidepressivos em amostras de plasma humano para análises toxicológicas de urgência, após a ingestão acidental ou suicida de doses altas de medicamentos.

Polythiophene (PTh) phase electropolymerized on the stainless steel wire was evaluated as solid-phase microextraction (SPME), and analysis by liquid chromatography with spectrophotometric detection (LC-UV) for determination of new-generation antidepressants, selective serotonin reuptake inhibitors (SSRIs) (citalopram, paroxetine, fluoxetine and sertraline), in plasma samples. The influence of electropolymerization variables (scan rate, potential range and scan cycles) was evaluated on SPME performance. The SPME variables (extraction time, temperature, matrix pH, ionic strength and desorption procedure), as well as the influence of plasma proteins on sorption mechanisms were also evaluated. The SPME/LC-UV method developed for determination of antidepressants in plasma sample presented a linear range between the limit of quantification (LOQ, 200-250 ng mL-1) to 4000 ng mL-1, and interday precision with coefficient of variation (CV) ranged from 11 to 15%. The proposed method can be a useful tool for the determination of antidepressants in human plasma samples in urgent toxicological analysis after the accidental or suicidal intake of higher doses of medications.

O presente trabalho descreve a aplicação bem sucedida da microextração em sorvente empacotado e cromatografia líquida com detecção de arranjo de diodos (MEPS/LC-DAD) para a determinação simultânea das sulfonamidas (sulfacetamida, sulfadiazina, sulfatiazol, sulfametazina sulfametoxipiridazina e sulfametoxazol) em amostras de ovos. As variáveis MEPS (pH da amostra, número de ciclos aspirar/dispensar, força iônica e procedimento de dessorção) foram otimizados para aumentar a sensibilidade analítica do método. O método apresentou linearidade na faixa de concentração de 30 ng g-1 (limite de quantificação, LOQ) a 300 ng g-1. Este valor de LOQ é inferior ao limite máximo de resíduo (LMR) preconizado para sulfonamidas em amostras de ovos (100 µg kg-1). As taxas de recuperação foram adequadas para todos os analitos (> 94%), bem como os dados de precisão inter-ensaio, com coeficientes de variação inferiores a 10%. Com base na validação analítica, a metodologia MEPS/LC é adequada para a determinação de sulfonamidas em amostras de ovos.

The present work describes a successful application of microextraction packed sorbent and liquid chromatography with diode array detection (MEPS/LC-DAD) for simultaneous determination of the sulfonamides (sulfacetamide, sulfadiazine, sulfathiazole, sulfamethazine, sulfamethoxypiridazine and sulfamethoxazole) in egg samples. The MEPS variables (pH of the sample, draw-eject cycles, ionic strength, and desorption procedure) were optimized, in order to improve the sensitivity of the proposed method. The method was shown to be linear at concentrations ranging from 30 ng g-1 (limit of quantification, LOQ) to 300 ng g-1. This LOQ value is lower than those established as the maximum residue limit (MRL) for egg samples (100 µg kg-1). The accuracy values were adequate for all analytes (> 94%), as well as the inter-day precision data, with coefficient of variation lower than 10%. On the basis of analytical validation, the MEPS/LC methodology has been shown to be a promising alternative for analysis of sulfonamides in egg samples.

Neste trabalho, o método de precipitação de proteínas e cromatografia líquida de alta eficiência com detecção de fluorescência (PP/CLAE-fluorescência) foi desenvolvido para a análise enantioseletiva da fluoxetina e norfluoxetina em amostras de plasmas. Diferentes agentes precipitantes, como solventes orgânicos, ácidos e sais, em diferentes proporções, foram avaliados. Segundo testes calorimétricos de Bradford, dentre todos os agentes precipitantes avaliados, a acetonitrila apresentou maior eficiência, considerando o número de etapas requeridas e a porcentagem de precipitação de proteínas (99,7%), quando adicionado na proporção de 3:1 (agente precipitante: plasma, v/v). O método PP/CLAE-fluorescência apresentou limite de quantificação de 30 ng mL-1 e intervalo linear de 30 a 1000 ng mL-1 com coeficientes de regressão linear acima de 0,9973 para os quatro enantiômeros. Em conclusão, o método PP/CLAE-fluorescência padronizado e validado proposto neste estudo foi aplicado com sucesso na análise de amostras de plasma de pacientes em terapia com a fluoxetina.

In this study, the enantioselective analysis of fluoxetine and norfluoxetine in plasma samples was performed by the protein precipitation method and high performance liquid chromatography with fluorescence detection (PP/LC-FD). Different precipitating agents - organic solvents, acids, and salts - in several proportions were available. The Bradford colorimetric method employed for evaluation of the efficiency of protein precipitation, has shown that for the sake of simplicity and percentage of protein precipitation (99.7%), acetonitrile was most effective when added at a ratio of 3:1 (acetonitrile/plasma, v/v). The quantification limit of the PP/LC-FD method was 30 ng mL-1 for the four enantiomers. The response of the proposed method was linear over a dynamic range from LOQ to 1000 ng mL-1, with correlation coefficients higher than 0.9973. In conclusion, the PP/LC-FD method can be successfully used to analyze plasma samples from ageing patients undergoing therapy with fluoxetine.

A new solid phase microextraction (SPME) system, known as in-tube SPME, was recently developed using an open tubular fused-silica capilary column, instead of an SPME fiber, as the SPME device. On-line in-tube SPME is usually used in combination with high performance liquid chromatography. Drugs in biological samples are directly extracted and concentrated in the stationary phase of capillary columns by repeated draw/eject cycles of sample solution, and then directly transferred to the liquid chromatographic column. In-tube SPME is suitable for automation. Automated sample handling procedures not only shorten the total analysis time, but also usually provide better accuracy and precision relative to manual techniques. In-tube SPME has been demonstrated to be a very effective and highly sensitive technique to determine drugs in biological samples for various purposes such as therapeutic drug monitoring, clinical toxicology, bioavailability and pharmacokinetics.

Os processos de adsorção e dessorção dos herbicidas ametrina, atrazina e metolaclor foram estudados em cinco solos brasileiros com diferentes conteúdos de matéria orgânica, utilizando-se cromatografia gasosa de alta resolução (HRGC). As linhas de regressão geradas apresentaram coeficiente de determinação > 0,964, indicando um bom ajuste dos dados à equação de Freundlich. O equilíbrio de adsorção foi atingido em aproximadamente 6 h. Histerese foi observada nas isotermas de adsorção e dessorção. Correlações significativas foram encontradas entre o coeficiente de adsorção, matéria orgânica e capacidade de troca de cátions. Não foram observadas correlações entre o coeficiente de adsorção dos herbicidas (ametrina, atrazina e metolaclor) e solubilidade em água, pKa e massa molecular destes compostos, pois estes herbicidas não pertencem à mesma família química. Por este fato, as correlações entre adsorção e propriedades dos herbicidas citadas acima foram estabelecidas somente entre as triazinas. O coeficiente de adsorção das triazinas mostrou-se diretamente correlacionado com a solubilidade em água, pKa e massa molecular destes compostos nos solos avaliados.

The sorption and desorption of herbicides ametryn, atrazine and metolachlor were studied in five Brazilian soils with various organic matter contents using high resolution gas chromatography (HRGC). The regression lines generated presented a coefficient of determination > 0.964, which indicates a good fit of the data by the Freundlich equation. Sorption reached an apparent equilibrium in the soils within approximately 6 h. Hysteresis was observed in both sorption and desorption isotherms. Significant correlations were found among sorption of herbicides, organic matter, and cation-exchange capacity. No relationship was found between adsorption of the herbicides (ametryn, atrazine, and metolachlor) and their water solubility, pKa, and molecular mass, since these herbicides do not belong to the same chemical family. On account of this, the relationship between sorption and herbicide properties cited above was established only for s-triazines. The s-triazine adsorption showed a direct relationship with water solubility, pKa and molecular mass of these compounds on the studied soils.