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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Stanovení stechiometrie komplexu aktivního metabolitu dexrazoxanu ADR-925 s železem a mědí standardní Jobovou metodou / Assessment of the complex stoichiometry of the active dexrazoxane metabolite ADR-925 with iron and copper by the standard Job's method

Szotáková, Tereza January 2018 (has links)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology and Toxicology Candidate: Tereza Morávková Supervisor: Assoc. Prof. Přemysl Mladěnka, Pharm.D., Ph.D. Title of Thesis: Assessment of the complex stoichiometry of the active dexrazoxane metabolite ADR-925 with iron and copper by the standard Job'smethod Iron and copper are important trace elements which participate on many physiological processes in humans. Their kinetics in the organism is tightly regulated since both lack or excess of these elements are associated with pathological states. Free ions of iron and copper can catalyse reactive oxygen species (ROS) production and hence cause damage to proteins and DNA. Imbalance in these metals is linked with diabetes, cardiotoxicity, cirrhosis of the liver and neurodegenerative diseases as Alzheimer's disease or Parkinson's disease. Dexrazoxane is a drug with documented protecting effect against cardiotoxicity of anthracyclines. A former theory associated its protective effects against these cytotoxic drugs with the iron-chelating properties of its active metabolite ADR-925. The goal of this diploma thesis was to explore if ADR-925 is able to chelate Fe2+ , Fe3+ , Cu+ a Cu2+ ions at physiologically and pathophysiologically relevant pH values (4,5; 5,5; 6,8 and 7,5) and...
2

Stanovení pKa huminových kyselin pomocí UV/VIS spektrometrie / Determination of pKa of humic acids by means of UV/VIS spectrometry

Kratochvílová, Romana January 2012 (has links)
The behaviour of humic acids in aqueous solutions is closely connected to the content of acid functional groups and their dissociation abilities. The titration methods are the most often used for the research of acid-base characteristics of humic acids, their results should lead to the determination of the content of functional groups and their pKa. However the determined values depend on many factors including the titration speed. The spectrophotometric determination of dissociation constant was used in this diploma thesis. Reliability of this method was confirmed in bachelor thesis where is mentioned that spectrophotometric determination of pKa corresponds with realistic dissociation behaviour of humic acids in the water much more better than values obtained from titration methods. The principle of newly used spectrophotometry method is the preparation of humic acids solutions in three different media with different pH values. Acid groups of humic acids are practically completely dissociated in intensely basic environment and the measured absorbance is caused by anion of „humate“. On the contrary their dissociation in acid environment is suppressed so much that we measure the absorbance of non-dissociated molecules of humic acids. Deionized water was used like neutral solvent. Water was replaced by acetic buffer in this thesis because of water’s properties which have significant influence on solutions' pH. Buffer was used for diluting or for solubilisation and in these both cases more stable pH values were occurred. The aim of this diploma thesis is investigate UV/VIS spectra of various solutions of humic acids with different values of pH and determinate mean value of pKa of humic acids which could be used like comparison of dissociation behaviours for vary samples. Values of acid dissociation constant were determined from measured dates and compared with values obtained by titration method. The UV/VIS spectra gained in combination with the results of pH measuring and the conductivity next showed the differences in the behaviour of differently prepared samples of humic acids.
3

Inkorporace nízkomolekulárních a vysokomolekulárních látek do vezikulárních systémů / Incorporation of low molecular weight and high molecular weight substances into vesicular systems

Geistová, Karolína January 2021 (has links)
This master´s thesis deals with the study of the incorporation of low and high molecular weight substances into liposomal systems. The aim of the work was to determine the encapsulation efficiency (EE) of the active substance and the influence of individual components of the liposomal system on EE. Liposomes were prepared from dipalmitoylphosphatidylcholine. They were stabilized by cholesteroland and phosphatidic acid was added to give a negative charge. Stealth properties gain the binding of polyethylene glycol and other trimethyl chitosan we enabled the entry of liposomes into the bloodstream by the paracellular pathway. Vitamin C and the enzyme bromelain were used for incorporation into liposomes. UV-VIS spectrophotometry was used to determine the encapsulation efficiency of liposomes prepared by combining the individual components. It has been suggested that vitamin C and the enzyme can be incorporated into liposomes, but an enzyme with a higher EE. Furthermore, phosphatidic acid and trimethyl chitosan have been found to affect EE, which increases the EE of vitamin C and decreases the EE of the enzyme.
4

Optimalizace extrakce pigmentů z buněk kvasinek a řas / Optimization of extraction of pigments from yeast and algae cells

Šimanský, Samuel January 2020 (has links)
The presented diploma thesis deals with the extraction and storage stability of lipophilic pigments produced by selected strains of yeasts and algae. In this thesis, there was studied the influence of the selected solvents on the efficiency of extraction, as well as the effect of ambient temperature on the stability of the pigments during storage. The work is divided into two main parts, theoretical and practical part. In the theoretical part knowledge about algae, yeasts and their cultivation parameters is summarized. Furthermore, some information regarding the selected lipid metabolites, their properties and possibilities of application in various branches of industry is mentioned. The practical part deals with the preparation of extracts and stability tests. Extracts were prepared from selected biomass samples in solvents suitable for applications in food industry or cosmetics (ethanol and hexane). Subsequently, the long-term stability tests lasting 4 months and short-term stability tests lasting a total of 28 days were performed on these extracts. The pigments were determined by HPLC and spectrophotometrically, the fatty acid content was determined by GC. For the extraction of pigments from biomass, in the most cases ethanol appears to be the optimal solvent. However, for lipid extraction from biomass, hexane appears to be the optimal solvent for a significant number of samples. In most samples, storage in the freezer showed the most favourable effect on pigment stability, but some samples showed comparable stability even when stored in the refrigerator.
5

Interakce huminových hydrogelů s měďnatými ionty / Interactions of humic hydrogels with cupric ions

Lang, David January 2014 (has links)
This diploma thesis deals with humic acid gels and their ability to bind metallic ions on their surface. In the thesis, there was studied the adsorption of copper ions on the provided gels. The gels were prepared by dissolving the humic acid in sodium hydroxide or sodium tripolyphosphate and then precipitated with hydrochloric acid or metal chlorides. Adsorption was studied at different concentrations of the copper (II) chloride and measured on UV-VIS spectrophotometer. It was proved from measuring that gels made from sodium tripolyphosphate are adsorbing less copper ions than the ones prepared by sodium hydroxide. Also, the copper ions are bound with smaller force on gels prepared with polyphosphate. Gels precipitated with magnesium chloride adsorb much more than gels precipitated with acid, thus in the case of gels sequestered metal ions extracted higher.
6

Analýza šťáv vybraných odrůd červeného a bílého rybízu / Analysis of juices of selected red and white currant varieties

Černá, Anna January 2015 (has links)
Presented diploma thesis deals with the analysis of juices of selected red and white currant varieties. The theoretical part is dedicated to the characteristics of a currant, biologically active substances of its fruits, its growing proces and the utilization of currants in the food industry. The analyzed parameters of currants - phenolics, anthocyanins and vitamin C are also characterized in the theoretical part with possibůe methods of their determination. The experimental part is devoted to the preparation of samples and the working practices of individual analysis. Six selected varieties of white and eleven varieties of red currant from Research and Breeding Institute of Pomology Holovousy Ltd. and six varieties of white and ten varieties of red currant from private grower were used for the analysis. Total phenolics and anthocyanins were determined spectrophotometrically, the content of vitamin C was determined by HPLC. Higher values of these compounds were measured mainly in the varieties of Research and Breeding Institute of Pomology Holovousy Ltd. Varieties of red currants contained higher amounts of total phenolics and anthocyanins while white currants contained higher amounts of vitamin C.
7

Determinação espectrofotométrica de sulfato em águas de chuva em um sistema de análises químicas em fluxo envolvendo troca-iônica / Spectrophotometric determination of sulphate in rain waters using a flow injection system with ion-exchange

Gomes, Taciana Figueiredo 05 April 2013 (has links)
Um sistema de análises químicas por injeção em fluxo foi desenvolvido e aplicado à determinação espectrofotométrica de baixas concentrações de sulfato em águas de chuva. O método explora a reação de deslocamento entre o ânion sulfato e o complexo dimetilsulfonazo (III) de bário, Ba-DMSA, com consequente formação do sal pouco solúvel BaSO4. A solução com o complexo Ba-DMSA apresenta alta absortividade molar a 656 nm, e uma diminuição pronunciada na absorbância ocorre na presença de sulfato. Desta forma, o sinal analítico é registrado como pico invertido proporcional à concentração de sulfato na amostra. A presença de altas concentrações de dimetilsulfóxido, DMSO, no reagente favorece a intensidade do sinal analítico, por coordenar as moléculas de água, melhorando a sensibilidade do método. A utilização do tensoativo dodecilsulfato de sódio, SDS, determina também uma melhoria considerável na sensibilidade analítica, pois sua presença no ambiente reacional altera as condições de supersaturação. A sensibilidade e seletividade do procedimento são melhoradas incluindo-se uma etapa de troca iônica em linha, com resina aniônica Dowex 1-X8, para concentração do sulfato e separação dos íons interferentes em potencial. O sistema proposto é robusto e fornece resultados precisos (d.p.r. < 0,01) com frequência analítica de 30 determinações por hora. O consumo de DMSA é de 0,17 \'mü\'mol por determinação. A curva analítica se apresenta linear até 2,0 mg L-1 SO42- e os limites de detecção e de quantificação foram estimados em 0,01 mg L-1 SO42- e 0,04 mg L-1 SO42-. / A flow injection system was developed and applied to the spectrophotometric determination of low concentrations of sulphate in rain waters. The method exploits the displacement reaction involving the sulphate anion and the barium dimethylsulfonazo (III) complex, Ba-DMSA, with consequent formation of the slightly soluble BaSO4 salt. As the Ba-DMSA solution is characterized by a high molar absorptivity at 656 nm, a pronounced absorbance lessening is observed in the presence of sulphate. The analytical signal is then recorded as an inverted peak proportional to the sulphate content in the sample. Presence of dimethylsulphoxide, DMSO, at high concentrations in the reaction medium leads to an enhancement of the analytical signals, coordinating water molecules, thus improving the sensitivity of the method. Addition of the surfactant sodium dodecylsulphate, SDS, results also in a pronounced improvement in sensitivity, as its presence in the reaction medium alters the supersaturation conditions. The sensitivity and selectivity of the method were improved by including an in-line ion exchange mini-column with the anionic resin Dowex 1-X8 into the manifold, for sulphate concentration and separation from potential interfering ions. The proposed system is robust and provides accurate results (R.S.D. <0.01) at an analytical frequency of 30 determinations per hour. About 0.17 \'mü\'mol DMSA are consumed per determination. The analytical curve is linear up to 2.0 mg L-1 SO42- and the detection and quantification limits were estimated as 0.01 mg L-1 SO42- and 0.04 mg L-1 SO42-.
8

EFEITO DO TEMPO E TEMPERATURA DE EXTRAÇÃO NA COMPOSIÇÃO FENÓLICA E PROPRIEDADES FUNCIONAIS in vitro DE EXTRATO AQUOSO DE ROOIBOS VERMELHO ORGÂNICO Aspalathus linearis (fabaceae)

Santos, Jânio Sousa 29 July 2016 (has links)
Made available in DSpace on 2017-07-21T18:53:07Z (GMT). No. of bitstreams: 1 Janio Santos.pdf: 2918457 bytes, checksum: 102357b433cd6ca1bff688e4810640bc (MD5) Previous issue date: 2016-07-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Rooibos (Aspalathus linearis) is a leguminous shrub of African origin, which attention has been dedicated to its most important technological product: Aqueous extract (tea).Rooibos tea has a complex chemical composition with various quantities phenolic compoundsin addition to high levels of aspalathin, a dihydrochalcone found only in rooibos. Therefore, the objective of this study is to evaluate the effects of time and temperature of extraction the phenolic compounds and functional in vitro properties of aqueous extracts of fermented organic Aspalathus linearis. Initially been prepared by an aqueous 22 extracts seven experiment design red rooibos for evaluation of the linear and combined effects of temperature and extraction time. By means of spectrophotometric methods primarily extracts were evaluated for the effect of time and temperature of extraction the content of phenolic compounds, flavonoids, flavonols, hydrolyzable condensed tannins and ortho-phenolic antioxidant activity against the DPPH and ABTS radical, reducing capability iron and reducing total capacity. Posteriorly it was performed for identification and quantification phenolic compounds 19 by high-performance liquid chromatography. The third step was to evaluate the inhibitory activity of α-amylase and α-glucosidase in vitro and hemolytic profile of aqueous extracts of rooibos red in human erythrocytes. The principal component analysis (PCA) was used to associate the chemical composition, antioxidant activity, reducing capacity, and inhibition of enzymes (α-amylase and α-glucosidase). In a general way the extract that was subjected to the extraction process in the higher temperature of the design (85 °C) showed the highest levels of total phenolics, flavonoids, flavonols, hydrolyzable condensed tannins and ortho-phenolic and antioxidant activity against the DPPH and ABTS, as the reducing capacity of iron and reducing total capacity, with little influence of time.The antioxidant activity and reducing capacity of rooibos extracts were shown to be correlated with the content of phenolic compounds, flavonoids, flavonols and ortho-diphenols. The quercetin contents, isoquercitrin, and rutin and were correlated with ABTS, DPPH, FRAP and total capacity reduction.Thus, we can say that such compounds are in vitro directly linked functionality presented by the aqueous extract of rooibos. In relation the antimicrobial activity of the extracts at concentrations from 7.81 to 1000 mg L-1 were not been effective in inhibiting the growth of tested microorganisms.As regards the inhibitory activity of α-amylase and α-glucosidase in general, all analyzed samples showed similar values extract to inhibit 50% of enzyme activity (IC50).The tea extract at 80 °C for 10 min was used for hemolysis test in which it was observed that there was beneficial interaction with the erythrocytes, reducing the occurrence of erythrocyte hemolysis in the cell.Is possible to observe a decrease in haemolytic activity with increased concentration of rooibos extract, this characteristic indicates that inhibition of plasma hemoglobin release is dependent on the concentration of rooibos extract contained in the medium. However, overall, the extraction temperature is the mainpositive factor that influences these variables in organic red rooibos. / Rooibos (Aspalathus linearis) é um arbusto leguminoso de origem africana, cuja atenção tem sido voltada ao seu produtotecnológico mais importante: Extrato aquoso (chá).O chá de rooibos apresenta uma composição química complexa com quantidades de vários compostos fenólicos, além de níveis elevados de aspalatina, uma dihidrocalcona encontrada apenas em rooibos. De tal modo o objetivo do presente estudo foi avaliar os efeitos do tempo e temperatura na extração dos compostos fenólicos e propriedades funcionais in vitro de extratos aquosos de Aspalathus linearis orgânicofermentado. Inicialmente foram preparados por meio de um delineamento de experimento 22 sete extratos aquosos de rooibos vermelho para avaliação dos efeitos lineares e combinados da temperatura e tempo de extração. Por meio de métodos espectrofotométricos primeiramente os extratos foram avaliados quanto ao efeito do tempo e da temperatura de extração no teor de compostos fenólicos totais, flavonoides, flavonóis, taninos condensados hidrolisáveis e orto-difenólicos, atividade antioxidante frente aos radicais DPPH e ABTS, capacidade redutora do ferro e capacidade redutora total. Posteriormente à identificação e quantificação de 19 compostos fenólicos foram realizadas por meio de cromatografia liquida de alta eficiência acoplada à espectrometria de massas (LC-ESI-MS/MS). O terceiro passo foi avaliar atividade inibitória das enzimas α-amilase e α-glucosidasein vitro e o perfil hemolítico dos extratos aquosos de rooibos vermelho em eritrócitos humanos. A análise de componentes principais (PCA) foi usada para associar a composição química, atividade antioxidante, capacidade redutora, e inibição das enzimas (α-amilase e α-glucosidase). De modo geral o extrato que foi submetido ao processo de extração na maior temperatura do delineamento (85 °C) apresentou os maiores teores de compostos fenólicos totais, flavonoidestotai, flavonóis totais, taninos condensados hidrolisáveis e orto-difenólicose na atividade antioxidante frente aos radicais DPPH e ABTS, como na capacidade redutora do ferro e capacidade redutora total, com pouca influência do tempo. A atividade antioxidante e capacidade redutora dos extratos de rooibos mostraram-se correlacionadas com o teor de compostos fenólicos totais, flavonoides, flavonóis e orto-difenólicos.Os teores de quercetina, isoquercitrina, e rutina e foram correlacionados com ABTS, FRAP e capacidade redutora total. Assim, é possível afirmar que tais compostos quantificados estão diretamente ligados às funcionalidades in vitro apresentadas pelo extrato aquoso de rooibos. Em relação a atividade antimicrobiana, os extratos nas concentrações de 7,81 a 1000 µg mL-1 não foram eficazes em inibir o crescimento dos micro-organismos testados.No que diz respeito à atividade inibitória das enzimas α-amilase e α-glucosidase, todas as amostras analisadas mostraram valores similares de extrato para inibir 50% da atividade enzimática (CI50). O chá extraído a 80°C por 10 min foi usado para o teste de hemólise no qual foi constatado que ocorreu uma interação benéfica com os eritrócitos, diminuindo a ocorrência de hemólise nas células eritrocitárias. Observa-se uma diminuição da atividade hemolítica com o aumento da concentração do extrato de rooibos, tal característica aponta que a inibição da liberação de hemoglobina no plasma é dependente da concentração de extrato de rooibos contido no meio. Conclui-se de modo global, que a temperatura de extração é o fator de maior influência positiva nessas variáveis em rooibos fermentado orgânico.
9

Desenvolvimento de metodologia espectrofotométrica multivariada para o controle de qualidade da associação acido kojico e hidroquinona em dermocosméticos

Calaça, Giselle Nathaly 26 February 2010 (has links)
Made available in DSpace on 2017-07-24T19:38:02Z (GMT). No. of bitstreams: 1 Giselle Nathaly Calaca.pdf: 1144795 bytes, checksum: 67dd1a377ef4bf40b69d80c46ee27a58 (MD5) Previous issue date: 2010-02-26 / Fundação Araucária de Apoio ao Desenvolvimento Científico e Tecnológico do Paraná / Kojic Acid (KA) and Hydroquinone (HQ) are depigmenting agents used as skinwhitening cosmetics to treat dyschromias. The need for low cost analytical methodologies that enable quality control of this association is evident. Due to the characteristics such as high sensitivity, low cost and operational simplicity, this work aims to use spectrophotometry in the visible region and multivariate calibration tools, mainly Partial Least Squares Regression (PLSR) for quantitative etermination of KA and HQ. The method is based on the complexation of kojic acid with Fe3+ ion (λ = 494nm), while hydroquinone reduces Fe3+ ions to Fe2+, which complex with 1,10-phenanthroline (λ = 510nm). The quantitative determination of KA and HQ by conventional methods was performed by analytical curve, spectrophotometric additivity principle and first-derivative pectrophotometry, and the average errors were: 20,65% (HQ) and 469,91% (AK), 41,44% (HQ) and 47,11% (AK), 57,59% (HQ) and 156,72% (AK), respectively. The results of conventional methods were compared to PLSR, and the multivariate models with better predictive capacity used: spectral range from 350 to 800 nm, mean center data, 03 and 02 latent variables for kojic acid and hydroquinone, respectively. The mean relative errors obtained from these models were: 4,20% for AK and 6,05% for HQ, indicating that PLSR method showed better results for the quantification of analytes, when compared to conventional methods. The multivariate methodology developed was validated according to ANVISA criteria and then used for quantification of analytes in real samples, obtained from manipulation pharmacies of the region. / O Ácido Kójico (AK) e a Hidroquinona (HQ) são agentes despigmentantes freqüentemente comercializados em associações dermocosméticas de manipulação magistral, utilizadas no tratamento de discromias. A necessidade de metodologias analíticas de baixo custo que viabilizem o controle de qualidade dessa associação é evidente. Em função de características como alta sensibilidade, baixo custo e simplicidade operacional, o presente trabalho tem por objetivo a utilização da espectrofotometria na região do visível associada a métodos de calibração multivariada, principalmente Regressão de Mínimos Quadrados Parciais (PLSR) para determinação de AK e HQ. A metodologia proposta consiste na complexação de ácido kójico com o íon Fe3+ (λ = 494 nm), enquanto a hidroquinona reduz os íons Fe3+ a Fe2+, que por sua vez complexam com 1,10-fenantrolina (λ = 510 nm). A determinação quantitativa de AK e HQ pelos métodos convencionais de análise foi realizada via curva analítica, princípio da aditividade espectrofotométrica e primeira derivada, cujos erros relativos médios foram: 20,65% (HQ) e 469,91% (AK), 41,44% (HQ) e 47,11% (AK), 57,59% (HQ) e 156,72% (AK), respectivamente. Os resultados dos métodos convencionais foram comparados ao PLSR, sendo que os modelos de melhor capacidade preditiva empregaram: faixa espectral de 350 a 800 nm, dados centrados na média, 03 e 02 variáveis latentes para ácido kójico e hidroquinona, respectivamente. Os erros relativos médios obtidos a partir desses modelos foram: 4,20% para AK e 6,05% para HQ, evidenciando que o método PLSR apresentou melhores resultados para a quantificação dos analitos, quando comparado aos métodos convencionais. A metodologia multivariada desenvolvida foi validada segundo critérios da ANVISA e posteriormente utilizada para previsão dos analitos em amostras reais obtidas em farmácias de manipulação da região.
10

Determinação espectrofotométrica de sulfato em águas de chuva em um sistema de análises químicas em fluxo envolvendo troca-iônica / Spectrophotometric determination of sulphate in rain waters using a flow injection system with ion-exchange

Taciana Figueiredo Gomes 05 April 2013 (has links)
Um sistema de análises químicas por injeção em fluxo foi desenvolvido e aplicado à determinação espectrofotométrica de baixas concentrações de sulfato em águas de chuva. O método explora a reação de deslocamento entre o ânion sulfato e o complexo dimetilsulfonazo (III) de bário, Ba-DMSA, com consequente formação do sal pouco solúvel BaSO4. A solução com o complexo Ba-DMSA apresenta alta absortividade molar a 656 nm, e uma diminuição pronunciada na absorbância ocorre na presença de sulfato. Desta forma, o sinal analítico é registrado como pico invertido proporcional à concentração de sulfato na amostra. A presença de altas concentrações de dimetilsulfóxido, DMSO, no reagente favorece a intensidade do sinal analítico, por coordenar as moléculas de água, melhorando a sensibilidade do método. A utilização do tensoativo dodecilsulfato de sódio, SDS, determina também uma melhoria considerável na sensibilidade analítica, pois sua presença no ambiente reacional altera as condições de supersaturação. A sensibilidade e seletividade do procedimento são melhoradas incluindo-se uma etapa de troca iônica em linha, com resina aniônica Dowex 1-X8, para concentração do sulfato e separação dos íons interferentes em potencial. O sistema proposto é robusto e fornece resultados precisos (d.p.r. < 0,01) com frequência analítica de 30 determinações por hora. O consumo de DMSA é de 0,17 \'mü\'mol por determinação. A curva analítica se apresenta linear até 2,0 mg L-1 SO42- e os limites de detecção e de quantificação foram estimados em 0,01 mg L-1 SO42- e 0,04 mg L-1 SO42-. / A flow injection system was developed and applied to the spectrophotometric determination of low concentrations of sulphate in rain waters. The method exploits the displacement reaction involving the sulphate anion and the barium dimethylsulfonazo (III) complex, Ba-DMSA, with consequent formation of the slightly soluble BaSO4 salt. As the Ba-DMSA solution is characterized by a high molar absorptivity at 656 nm, a pronounced absorbance lessening is observed in the presence of sulphate. The analytical signal is then recorded as an inverted peak proportional to the sulphate content in the sample. Presence of dimethylsulphoxide, DMSO, at high concentrations in the reaction medium leads to an enhancement of the analytical signals, coordinating water molecules, thus improving the sensitivity of the method. Addition of the surfactant sodium dodecylsulphate, SDS, results also in a pronounced improvement in sensitivity, as its presence in the reaction medium alters the supersaturation conditions. The sensitivity and selectivity of the method were improved by including an in-line ion exchange mini-column with the anionic resin Dowex 1-X8 into the manifold, for sulphate concentration and separation from potential interfering ions. The proposed system is robust and provides accurate results (R.S.D. <0.01) at an analytical frequency of 30 determinations per hour. About 0.17 \'mü\'mol DMSA are consumed per determination. The analytical curve is linear up to 2.0 mg L-1 SO42- and the detection and quantification limits were estimated as 0.01 mg L-1 SO42- and 0.04 mg L-1 SO42-.

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