Desenvolvimento e validação de método analítico por cromatografia líquida de alta eficiência (CLAE) para determinação de associação de ampicilinas em pó liofilizado para injeção

An analytical method has been developed and validated for the determination of an association of ampicillins in a lyophilized powder for injection by HPLC. The advantage of chromatographic method other than the microbiological one is that, it is possible to monitor precisely, out-of-specification results in quality control processes and also during stability studies, in which an association of ampicillins is present. The proposed HPLC method was developed by using forced degraded samples, in order to reach a selective analysis of ampicillins when in the presence of their degradation products. It was possible to detect benzatine and through indirect calculation, to determine the ampicillin sodium in the drug sample. The method showed to be selective, accurate, precise, robust and linear (from 45.92 to 36.04 μg mL-1 of total ampicillin and from 14.53 to 43.28 μg mL-1 of benzatine). The accuracy determined from recovery test, gave results in the range of 99.41% of total ampicillin to 100.31% of benzatine. Hence, it can be concluded that the proposed HPLC method is applicable for ampicillins determination.

Nanoemulsões óleo de laranja/água preparadas em homogeneizador de alta pressão

The objective of this work was to use the high-pressure homogenizer (HPH) to prepare stable oil/water nanoemulsions presenting narrow particle size distribution. The dispersions were prepared using nonionic surfactants based on ethoxylated ether. The size and distribution of the droplets formed, along with their stability, were determined in a Zetasizer Nano ZS particle size analyzer. The stability and the droplet size distribution in these systems do not present the significant differences with the increase of the processing pressure in the HPH). The processing time can promote the biggest dispersion in the size of particles, thus reducing its stability.

Hidrólise do óleo de Azadirachta indica em água subcrítica e determinação da composição dos triacilglicerídeos e ácidos graxos por cromatografia gasosa de alta resolução a alta temperatura e cromatografia gasosa de alta resolução acoplada à espectrometria de massas

The development of modern analytical tools plays an important role in quality control. The main purpose of this study was to explore the use of subcritical water as a versatile analytical tool, employed simultaneously as a reagent and solvent, as well as the application of high temperature-high resolution gas chromatography (HT-HRGC) to develop a procedure for the analysis of triacylglycerides and fatty acids in Azadirachta indica A. Juss. (Neem) oil without the need for solvents, chemical reagents, or catalytic agents. The developed method presented satisfactory results and is in agreement with the concepts of Green Analytical Chemistry (GAC).

Caracterização de contaminantes presentes em sistemas de tratamento de esgotos, por cromatografia líquida acoplada à espectrometria de massas tandem em alta resolução

This work shows results on the characterization, by liquid chromatography coupled to high resolution tandem mass spectrometry (LC-IT-TOF-MS) with electrospray ionization, of organic compounds present in raw and treated effluents from a combined sewage treatment systems (upflow anaerobic sludge blanket-trickling filter). The sewage samples were prepared by C18 solid phase extraction and the spectra obtained from the various extracts were submitted to principal component analysis to evaluate their pattern and identify the major deprotonated species. Some target compounds were submitted to semiquantitative analysis, using phenolphtalein as internal standard. The results showed the anaerobic step had little impact on the removal of anionic surfactants (LAS), fatty acids, and some contaminantes such as bisphenol A and bezafibrate, whereas the aerobic post-treatment was very efficient in removing these organics.

Otimização e validação de método para determinação de ácidos orgânicos em vinhos por cromatografia líquida de alta eficiência

The organic acids (tartaric, malic, citric, lactic and succinic) are de main components responsible for the acidity in the wine. This method for simultaneous determination of organic acids and interfering peaks in wines can be achieved in 16 min. The sample preceded by a dilution and filtration step. The chromatographic separation required one reversed phase column, isocratic mobile phase (acetonitrila, formic acid in water) and detection wavelength was set at 212 nm. The validation confirmed good repeatability, recovery and application in red and white wines.

Fases estacionárias modernas para cromatografia líquida de alta eficiência em fase reversa

This review first discusses the limitations of many of the supports and stationary phases used in reversed phase high performance liquid chromatography and then describes those, developed more recently, that present better stabilities and more versatile selectivities. Emphases will be given to stationary phases that use higher purity silicas, hybrid silicas, monolithic silicas, metallic oxides and mixed oxides as supports and those that have embedded polar groups or contain phenyl or fluoro groups as the stationary phase as well as the phases used for mixed mode or hydrophilic interaction separations. These modern stationary phases facilitate the analysis of complex mixtures.

Degradação de corantes reativos por processo foto-fenton envolvendo o uso de peneira molecular 4A modificada com Fe3+

In this work the preparation and characterization of a supported catalyst intended for degradation of reactive dyes by Fenton-like processes is described. The photocatalyst was prepared by immobilization of Fe3+ into the molecular sieve (4A type) surface and characterized by x-ray diffractometry and infrared, Mössbauer and EPR spectroscopy. The solid containing 0.94% (w/w) of ferric ions was used in degradation studies of aqueous reactive-dyes samples with really promissory results. Generally, Vis-assisted photochemical processes leads to almost total decolorization of all tested dyes at reaction times lower than 30 min. It was also observed that the iron-molecular sieve matrix can be reused.

Reator de UV-Ozônio com lâmpada a vapor de mercúrio a alta pressão modificada para tratamento superficial de óxidos transparentes condutivos utilizados em dispositivos poliméricos eletroluminescentes

An UV-Ozone reactor was developed with an ignition tube extracted into HID mercury lamp used to irradiation on zinc oxide (ZnO) and fluorinated tin oxide (FTO) films for PLEDs devices. Different exposures times were used. In contact angle measurements revealed better results for ZnO and FTO by 15 and 5 min, respectively. In Diffuse Reflectance Infra-red Fourier Transformed (DRIFT) spectroscopy allowed the observation of water, hydrocarbon and carbon dioxide adsorbed on the untreated TCO surfaces. After the UV-Ozone treatment the contaminants were significantly reduced or eliminated and the PLEDs devices decreased threshold voltages in comparison with respectively untreated TCOs.

Validación de un método analítico empleando cromatografía líquida de alta eficiencia para la determinación de ibuprofeno en medios biorrelevantes

An analytical method by liquid chromatography has been proposed and validated to study the apparent solubility of ibuprofen in biorelevant dissolution media. The main properties of the studied media were pH values of 5.0 and 6.5 and the presence or absence of some natural surfactant agents. The parameters evaluated were specificity, linearity, precision, accuracy, and detection and quantification limits, as well as the drug stability under the analysis conditions. The developed method was useful to determine the apparent solubility of this drug as a function of temperature and surfactants concentration to demonstrate the validity of the Biopharmaceutics Classification System.

Validação e estimativa da incerteza de método para análise de licopeno e β-caroteno em polpa de tomate por cromatografia líquida de alta eficiência

A method to quantify lycopene and β-carotene in freeze dried tomato pulp by high performance liquid chromatography (HLPC) was validated according to the criteria of selectivity, sensitivity, precision and accuracy, and uncertainty estimation of measurement was determined with data obtained in the validation. The validated method presented is selective in terms of analysis, and it had a good precision and accuracy. Detection limit for lycopene and β-carotene was 4.2 and 0.23 mg 100 g-1, respectively. The estimation of expanded uncertainty (K = 2) for lycopene was 104 ± 21 mg 100 g-1 and for β-carotene was 6.4 ± 1.5 mg 100 g-1.

Fases estacionárias quirais para cromatografia líquida de alta eficiência

The development of Chiral Stationary Phases (CSPs) for high performance liquid chromatography has been studied by various researches around the world, especially, since 1980. This simple interest has been transformed into a tool of great technological value for the industrial community and scholars in general providing the existence of several CSPs, which act through different mechanisms of chiral discrimination. This paper describes the main types of CSPs that are used for the resolution of the majority of chiral compounds.

Determinação de 2,5-hexanodiona em urina empregando cromatografia líquida de alta eficiência, após derivatização com 2,4-dinitrofenil-hidrazina

A method for quantifying urinary 2,5-hexanedione was optimized and validated. Urine samples were hydrolyzed and derivatized with 2,4-dinitrophenylhydrazine. The analyte was separated in a high performance liquid chromatography system with a diode array detector, using a C18 column (150 x 4.6 mm, p.d. 5 µm) and a mobile phase composed of phosphate buffer pH 2.3:acetonitrile (40:60, v/v), at a flow rate of 1 mL/min. The chromatograms were monitored at 334 nm. Retention time was 7.3 minutes. Main validation parameters were: coefficient of determination: 0.9994, accuracy: 96 to 107%; intra-assay precision (RSD): 3.08 to 6.72%; inter-assay precision (RSD): 2.54 to 8.17% and limit of quantitation of 0.19 µg/mL.

Otimização de método para análise de folatos em hortaliças folhosas por cromatografia líquida de alta eficiência com detecção por fluorescência

We optimized a method for the determination of three main folate isoforms in leafy vegetables. Analysis was carried out by HPLC, using gradient of elution and fluorescence detection. Limits of quantification were 2 ng/mL; 2 ng/mL and 28 ng/mL for tetrahydrofolate (THF), 5-methyltetrahydrofolate (5-MTHF) and 5-formyltetrahydrofolate (5-FTHF), respectively. Recovery rates of THF, 5-MTHF and 5-FTHF varied from 87.86 to 100.64%; 88.12-94.22% and 89.82-106.69%, respectively. Test of repeatability showed relative standard deviation for peak areas lower than 10%. Tests for linearity showed high coefficients of determination. The results showed advances in folates extraction and analysis in raw and cooked leafy vegetables.

Aplicações de cromatografia líquida de alta eficiência para o estudo de poluentes orgânicos emergentes

Emerging organic pollutants (EOP) include many environmental contaminants based on commercial products such as pharmaceuticals, personal care products, detergents, gasoline, polymers, etc. EOP may be candidates for future regulation as they offer potential risk to environmental and human health due to their continual entrance into the environment and to the fact that even the most modern wastewater treatment plants are not able to totally transform / remove these compounds. High performance liquid chromatography is recommended to separate emerging organic pollutants with characteristics of high polarity and low volatility, especially pharmaceuticals, from environmental matrices.

Separação semipreparativa de α e β-amirina por cromatografia líquida de alta eficiência

The resin obtained from species of the genus Protium (Burseraceae) is formed mostly of pentacyclic triterpenes: α-amyrin and β-amyrin. The separation and purification of these triterpenes were optimized in three steps.