Determinação de corantes marcadores do tipo azo e antraquinona em combustíveis por cromatografia líquida com detecção eletroquímica

An analytical method based on high-performance liquid chromatography with electrochemical detection has been developed and applied to the determination of Solvent blue 14 (SA-14) and Solvent red 24 (SV-24) in fuel samples. The dyes were better separated on C18 column, using a mobile phase composed of acetonitrile and ammonium acetate (90:10, v/v). Detection was carried out at an oxidation potential of +0.85V. The detector response was linear at concentration range of 7.50×10-8 - 1.50×10-6 mol L-1 (r = 0.997) for SA-14 and SV-24, respectively. The method was used to quantify these dyes in fuels samples with satisfactory accuracy and precision.

Uso de CLAE no controle de qualidade em produtos comerciais de Nim: reprodutibilidade da ação inseticida

The Neem tree, Azadirachta indica, provides many useful compounds that are used as pesticides. However, the efficiency in field of products like neem oil can be committed because they have not been observed reproductive content of secondary metabolic like azadirachtin. Based on reverse-phase high-performance liquid chromatography (HPLC) a new method was developed to permit the rapid quantitative analysis of azadirachtin from seeds, extracts and oil of Neem. In the present study it was evaluated the azadirachtin quantitative variation among various Neem's extracts and seeds showing the importance of quality control for reproduction of the insecticide efficiency, using S. frugiperda as target insect.

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.

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.

Development and validation of a dissolution test for diltiazem hydrochloride in immediate release capsules

This work describes the development and validation of a dissolution test for 60 mg of diltiazem hydrochloride in immediate release capsules. The best dissolution in vitro profile was achieved using potassium phosphate buffer at pH 6.8 as the dissolution medium and paddle as the apparatus at 50 rpm. The drug concentrations in the dissolution media were determined by UV spectrophotometry and HPLC and a statistical analysis revealed that there were significant differences between HPLC and spectrophotometry. This study illustrates the importance of an official method for the dissolution test, since there is no official monograph for diltiazem hydrochloride in capsules.

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.

Identificação de alguns constituintes químicos de Indigofera hirsuta Linn. (Fabaceae) por CLAE-IES-EM (TOF) e avaliação da atividade antirradicalar

A rapid analytical approach, suitable to characterize the compounds present in the aqueous and methanol extracts prepared from the aerial parts of Indigofera hirsute, was developed. The method based on high-performance liquid chromatography coupled to mass spectrometry, electrospray positive ionization and detection by time of flight (HPLC-ESI-MS-TOF) identified, tryptophan, uracil, rutin, kaempferol-3-O-β-D-glucopyranoside, gallic acid and methyl gallate. The antiradical activity of this extract was evaluated using DPPH assay, with gallic acid as antiradical pattern. The study revealed the antiradical activity of methyl galatte (EC50 = 5 ± 0.3 µg mL-1) galic acid (EC50 = 5 ± 0.2 µg mL-1) and rutin (EC50 = 21.6 ± 0.6 µg m L-1), isolated from methanol extract (EC50 = 67.7 ± 0.9 µg mL-1), which showed strong antiradical activity.

Validação de método e determinação espectrométrica dos flavonoides das folhas e do vinhoto da cana-de-açúcar e comparação com método CLAE-UV

This paper reports on a modification of the procedures originally described in the French Pharmacopoeia for the UV-visible spectrometric analysis of flavonoids, and proposes a validation of the method and its application in the determination of total flavonoids from sugarcane (Saccharum officinarum) leaves and vinasse. An analysis of precision and accuracy revealed a low relative standard deviation (< 5.0%) and a good recovery percentages (99.79 and 98.34%). A comparison of the spectrometric results against those obtained by high performance liquid chromatography (HPLC-UV) demonstrated complete compatibility between the modified French Pharmacopoeia (spectrometric) and HPLC-UV methods

Desenvolvimento e validação de método analítico por CLAE para a quantificação simultânea de dipropionato de betametasona e fosfato sódico de betametasona em suspensão injetável

A reversed-phase HPLC method was developed and validated to separate and simultaneously quantify the association of betamethasone sodium phosphate (BP) and betamethasone dipropionate (BD) in injectable suspensions. Chromatographic conditions were ternary gradient elution at 1.6 mL/min on a C18 column with 254 nm. The linearity of the method was established in the range 120 to 280 mg/mL BD, and 48 to 112 mg/mL BP. The RSD of intermediate precision of the method was <1% and recoveries were 99-101% for both drugs. The method proved selective, linear, precise, accurate and robust for quantifying BP and BD in commercial injectable suspensions.

Desenvolvimento e validação de método analítico para quantificação do fármaco bevacizumabe por cromatografia a líquido de alta eficiência

In this study, an analytical method was developed and validated for quantitation of the drug bevacizumab (Avastin®) by high performance liquid chromatography (HPLC). The HPLC column was a BioSuite 250® HR SEC, 300 x 7.8 mm x 5 µm (Waters, USA). The mobile phase consisted of phosphate buffered saline (PBS). The results revealed that the method was specific, precise, accurate, robust and linear (r² = 0.998) from 5 to 75 µg mL-1. Therefore, this method can be used in drug release studies or in quality control ampoules of the drug.

Desenvolvimento e validação de método para o doseamento de tibolona em cápsulas por cromatografia líquida de alta eficiência

Tibolone is a synthetic steroid used for prevention of bone loss and treatment of menopause symptoms. This article describes the development and validation of an analytical method to quantify tibolone in capsules using high performance liquid chromatography with UV detection. After chromatography conditions are established the validation parameters evaluated were specificity, linearity, precision, accuracy, detection and quantification limits and robustness. The method developed is effective to analyze tibolone in capsules, being able to be used in quality control laboratory routine.

Biodegradação de paclobutrazol por Pseudomonas spp. em sistemas de solo saturados

Paclobutrazol is growth regulator of plants that has low mobility in soil and therefore has accumulated. The objective of this study was to investigate the paclobutrazol biodegradation in two soils from the São Francisco River Valley. The biodegradation experiments were conducted in batch using paclobutrazol and paclobutrazol added glycerol. The experiments were performed in sterile and nonsterile conditions using a mixed culture of Pseudomonas. The concentration of paclobutrazol was determined by high performance liquid chromatography. The biodegradation reached 43% in 14 days of experiments with only paclobutrazol and 70% in 28 days of experiments that contained glycerol and paclobutrazol.

Desenvolvimento e validação de métodos analíticos para determinação de ácido glicirrízico, ácido salicílico e cafeína em nanopartículas de quitosana e alginato

The present work consists of the development and validation of analytical method for evaluation of glycyrrhizic acid, salicylic acid, and caffeine in chitosan-alginate nanoparticles by high performance liquid chromatography. Method validation investigated parameters such as linearity, precision, accuracy, robustness and specificity, which gave results within the acceptable range. The methods were applied to nanoparticles suspensions containing the drugs and were able to determine the entrapment efficiency successfully. The best entrapment efficiency was achieved with the glycyrrhizic acid (95.4%).