Otimização e aplicação da microextração em fase sólida com e sem refrigeração interna em amostras de ervas medicinais e água de rio

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas. Programa de Pós-Graduação em Quimica, Florianópolis, 2013A microextração em fase sólida no modo de extração headspace (HS-SPME) e a microextração em fase sólida com recobrimento internamente refrigerado no modo headspace (HS-CF-SPME) foram utilizadas para a determinação do perfil volátil de amostras de ervas medicinais comumente encontrados no sul do Brasil. Otimizações multivariadas permitiram o estabelecimento das condições de extração para ambos procedimentos e as análises foram feitas por cromatografia gasosa. Foi testada a utilização de duas temperaturas da fibra no mesmo procedimento de extração, sendo posteriormente comparados os procedimentos, tendo a estratégia baseada em utilizar duas temperaturas da fibra apresentado melhor desempenho levando em conta a totalidade de compostos. A utilização de dois modos de extração (imersão direta e headspace) e duas temperaturas de extração em um mesmo procedimento de SPME para a determinação simultânea de trihalometanos e pesticidas organoclorados em amostras aquosas também foi estudada. Otimizações multivariadas para a escolha das melhores formas de extração (headspace e imersão direta) forma aplicadas. A partir desta otimização foi construída a curva de calibração para os compostos estudados sendo obtidos resultados satisfatórios quanto aos parâmetros analíticos de mérito e a aplicabilidade foi testada em amostras de água do rio Araranguá - SC.Abstract : The solid phase microextraction in headspace extraction mode (HSSPME) and internally-cooled-solid phase microextraction in headspace mode (HS-CF-SPME) were used for determining the volatile profile in samples of herbs commonly found in southern Brazil, such as sage, artichoke, fennel, peppermint, macela and chamomile. Multivariate optimizations allowed the determination of the extraction conditions for both procedures and analyzes were performed by gas chromatography with flame ionization detector (GC-FID) the responses were the geometric means of extracted compounds. The optimized conditions for the HS-SPME procedure were 60 °C and 40 min respectively for temperature and extraction time. For the HS-CF-SPME procedure the optimized condition was extraction temperature 60 °C and the extraction time of 15 min with the fiber coating temperature optimized at 5 °C. The use of two fiber temperatures in the HS-CF-SPME procedure in order to extract volatile and semi-volatile compounds has been optimized , were used 60 °C in first 7.5 min and 5 °C in 7.5 min remaining, on a total extraction time of 15 min. Both procedures HS-CF-SPME were compared, and the HS-CF-SPME procedure with one fiber temperature performed better only for the more volatile compounds, and the strategy of using two fiber temperatures showed better performance for all compounds. It was also possible to determine the volatile profile of each herb studied by this sample praparation technique using gas chromatography and mass spectrometry (GC-MS). The use of two extraction modes (direct immersion and headspace) and two extraction temperatures in the same SPME procedure to simultaneous determination of trihalomethanes (THM) and organochlorine pesticides in aqueous samples was studied. Multivariate optimizations for the choice of the best extraction conditions (headspace and direct immersion) so applied. Regarding the use of two modes of simultaneous extraction in a single extraction procedure, the ideal conditions were extraction time of 70 min, 28 min in the HS-SPME mode at 12 °C (favoring the extraction of THM) and 42 min in the DISPME mode at 80 °C (favoring the extraction of organochlorine pesticides). From this optimization was made a calibration curve for the compounds studied were obtained correlation coefficients above of 0.98; percentage of recovery between 90.8 - 103.7% and relative standard deviations between 11.4 e 17.9%, both this dates were obtained to concentrations of 20 ?g.L-1 being the arithmetic mean of triplicates (n=3). After, this procedure was applied in water samples collected from the river Araranguá - SC

Desenvolvimento e aplicação de estratégias alternativas para a microextração em gota única e microextração em fase sólida utilizando líquidos iônicos poliméricos

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas, Programa de Pós-Graduação em Química, Florianópolis, 2016.Neste trabalho foram abordadas novas metodologias de extração para duas técnicas de preparo de amostras distintas, a microextração em gota única (SDME) e a microextração em fase sólida (SPME). Essa abordagem consistiu na utilização, sequencialmente, dos modos de imersão direta (DI) e headspace (HS) em um mesmo procedimento de microextração com a finalidade de permitir extrações eficientes de compostos com comportamentos físico-químicos bastante distintos. Primeiramente, com a utilização da SDME, foram realizadas extrações/determinações de hidrocarbonetos voláteis incluindo benzeno, etil benzeno, xilenos e também trihalomentanos e hidrocarbonetos policlicos aromáticos em amostras de água de torneira por cromatografia gasosa acoplada ao espectrômetro de massas (GC-MS). As condições de extração para a nova metodologia foram otimizadas bem como os resultados obtidos foram comparados ao procedimento convencional. A nova abordagem chamada DI-HS-SDME proporcionou extrações eficientes dos analitos com distintas volatilidades, permitindo uma condição de extração compromisso entre as classes de compostos estudadas. Num segundo estudo, desta vez com a utilização da SPME e fases extratoras compostas de líquidos iônicos poliméricos e também com a aplicação do modo DI-HS, foram determinados 21 compostos de diferentes classes em água de torneira e de lago por GC-MS. Da mesma forma, as condições de extração foram otimizadas e as eficiências foram comparadas. Neste caso, a seletividade principalmente para hidrocarbonetos policíclicos aromáticos foi aumentada em virtude da utilização de líquidos iônicos poliméricos que possuíam em sua estrutura grupos aromáticos. Num terceiro estudo, pela primeira vez foram sintetizadas e aplicadas fases extratoras compostas por líquidos iônicos poliméricos compatíveis com cromatografia líquida (LC). Essas fases mostraram-se extremamente robustas mesmo com a utilização de dessorção líquida nos solventes tipicamente utilizados. Os recobrimentos poliméricos foram caraterizados, as condições de extração foram otimizadas e a seletividade de cada recobrimento foi avaliada frente à extração de fenóis, inseticidas e fármacos em amostras de água de lago e de torneira.Abstract : In this work, new extraction methodologies for two different sample preparation techniques, single drop microextraction (SDME) and solid-phase microextraction (SPME) are presented. These approaches consisted of using direct immersion (DI) and headspace (HS) modes, sequentially, in the same microextraction procedure to allow efficient extractions of compounds with huge difference in their physico-chemical behaviors. First, using SDME, the extraction/determination of volatile hydrocarbons including benzene, ethylbenzene, xylenes and also trihalomethanes and polycyclicaromatic hydrocarbons from tap water samples were performed using gas chromatography ? mass spectrometer (GC-MS). The extraction conditions were optimized and results were compared to a conventional procedure. The new approach called DI-HS-SDME provided efficient extractions of the analytes with different volatilities, allowing a compromise extraction condition among the classes of compounds. In a second study, using SPME and extraction phases comprised of polymeric ionic liquids, and also applying the DI-HS sampling mode, 21 analytes of different chemical classes were determined from tap and lake water samples using GC-MS. Likewise, the extraction conditions were optimized and the extraction efficiencies were compared. In this case, the selectivity for polycyclic aromatic hydrocarbons was increased due to the use of polymeric ionic liquids with aromatic groups in their structure. In a third study, extraction phases comprised of polymeric ionic liquids compatible with liquid chromatography (LC) were synthesized and applied for the first time. These phases exhibited extremely robust behavior even using the typical solvents for liquid chromatography. The sorbent coatings were characterized, the extraction conditions were optimized and the selectivity of each coating was evaluated for the extraction of phenols, pesticides and pharmaceuticals from lake and tap water samples

Development of a fast screening method for the direct determination of chlorinated persistent organic pollutants in fish oil by high-resolution continuum source graphite furnace molecular absorption spectrometry

The authors are grateful to the Conselho Nacional de Desenvolvimento Científico and Tecnológico (CNPq); the present research was mostly financed through Project no. CNPq 406877/2013-0. The authors are also grateful to the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for financial support and scholarships, and to Analytik Jena for financial support and donation of the contrAA 600 high-resolution continuum source atomic absorption spectrometer.Peer reviewedPostprin

Analysis of seized stanozolol formulations in South Brazil by liquid chromatography coupled to quadrupole time-of-flight-mass spectrometry

Anabolic-androgenic steroids (AAS) are synthetic derivatives of testosterone which are used medically for several diseases. However, misuse is commonly observed by athletes to promote enhancement of strength and performance. AAS are frequently obtained through online black markets from clandestine drug manufacturing laboratories, without any quality standards, being potentially dangerous for users. The purpose of this work was the development and application of a fast and simple procedure for the quantitation of stanozolol by liquid chromatography coupled to quadrupole time-of-flight-mass spectrometry (LC-QTOF-MS) in tablets packs seized in Rio Grande do Sul state, Brazil. The samples of stanozolol were separated considering its dosage form. The internal standard (methyltestosterone) was added to the aliquots of the samples, dissolved in methanol and 5μL were injected into the analytical system. The newly developed method has been validated for lower limit of quantitation (LLOQ), linearity, accuracy, precision and selectivity. The LLOQ was 0.1 µg/mL. The developed method was successfully applied to 31 samples seized by the Secretaria da Receita Federal do Brasil (a Brazilian federal revenue service agency). According to the results, 90.3% of the suspected medicines (n=31) were adulterated, and 65% exhibited higher concentrations of stanozolol than those indicated in the label. This work successfully established a new method for quantification of stanozolol using LC-QTOF-MS. This method aims at contributing to the identification and quantification of this anabolic androgenic steroid frequently seized by federal inspection agencies

Application of Parallel-DPX for the determination of potential cancer biomarkers in urine samples using cork as natural extraction phase followed by GC–MS

Early-stage diagnosis is important to discover possible cancers in the human body. Bioanalytical methods are tools that allow for these studies. Biogenic amines are markers of several cancers in the organism, such as colorectal, lung and pancreatic. In this study, the determination of three important amines, putrescine (Put), spermidine (Spd) and cadaverine (Cad), was proposed. The use of Parallel-DPX-Cork is demonstrated for the first time in this type of application, permitting an effective methodology based on Green Analytical Chemistry (GAC) principles, with separation/quantification by GC–MS in human urine. Multivariate and univariate designs were applied, and the sample was prepared as follows: 10 min for alkaline hydrolysis under agitation with NaOH (2 mol L−1), added in a proportion of 1:8 (v/v) with the sample, at 60 °C, followed by 10 min of centrifugation at 3500 rpm, 5 min for derivatization with chloroformate isobutyl (180 µL), sample pH adjusted at 12; the extraction step was performed using 6 cycles, with 2 mL for each cycle (totalizing 12 mL of sample per experiment) and 25 mg of cork; the desorption step was carried out using 2 cycles with ethyl acetate (300 µL). LODs and LOQs were 15.2 and 50 ng mL−1 for all analytes. Intraday and interday precisions ranged from 2 to 22% and 9 to 28%, respectively. For the relative recoveries, the range was 62% to 130%. Five urine samples, collected from male and female volunteers, were analyzed using the methodology proposed, and the analytes concentrations obtained lower than LOQ and LOD