ABSTRACT
The present work describes the in vitro biological activities of the crude extracts (petroleum ether, ethyl acetate and n-butanol) prepared from the species Ephedra altissima Desf. The estimation of total phenolic, flavonoid and tannin contents were carried out using the Folin-Ciocalteu, trichloroaluminum and acidified vanillin methods, respectively. The evaluation of the in vitro antioxidant activities were performed by three different methods namely: scavenging of the free radical ABTS, permanganate reducing antioxidant capacity, and potentiometric assay. In addition, the antibacterial activity was assessed by the agar disk diffusion assay against seven bacterial strains. The results of the phytochemical screening revealed the presence of several types of secondary metabolites. The EtOAc extract exhibited the highest content of phenols (125.62 ± 1.51 & 956;g EGA mg-1 of extract). The greatest flavonoid and tannin contents were observed for n-BuOH extract (19.18 ± 0.39 µg EQ mg-1 of extract and 8.95 ± 1.70 & 956;g EC mg-1 of extract, respectively). Moreover, the EtOAc extract revealed potent antioxidant activity in all the tested methods. Furthermore, the aqueous extract from the species E. altissima showed a good ability to reduce iron III to iron II with a value of 0.68 ± 0.3 moL eq L-1 in potentiometric assay. All the crude extracts (PE, EtOAc and n-BuOH) displayed inhibition of bacterial growth against at least three strains with values of MIC ranging from 3.125 to 50 µg mL-1. Therefore, these results suggest that Ephedra altissima could be used as an important source of natural bioactive compounds with antioxidant and antibacterial properties.
Subject(s)
Anti-Bacterial Agents , Antioxidants , Phytochemicals , Ephedra/immunology , Ephedra/microbiology , Ephedra/chemistryABSTRACT
Resumen Se evaluaron diferentes sistemas de medición para titulaciones ácido-base, con el propósito de determinar cuál presenta mejores características metrológicas. Estos sistemas incluyen volumetrías y gravimetrías, las cuales se combinaron con diferentes métodos de detección del punto de equivalencia: (i) potenciometría, (ii) indicador ácido-base y (iii) conductividad electrolítica. Este artículo propone una nueva aproximación para la estimación de la incertidumbre de medición asociada a la detección del punto de equivalencia. Los resultados indicaron que, para la determinación del punto de equivalencia, las incertidumbres más bajas se obtienen mediante el método potenciométrico en comparación con el método conductimétrico cuyo sesgo es hasta 78 veces mayor. Sin embargo, se encontró que el método potenciométrico es fuertemente dependiente de la resolución del instrumento y/o la cantidad de agente titulante que se adiciona en la cercanía al punto de equivalencia. También se encontró que la incertidumbre disminuye cerca del 40% empleando métodos gravimétricos en comparación con los volumétricos. Al realizar la evaluación del sesgo de los sistemas de medición acorde con la guía ISO 33:2015, los resultados mostraron que, de los métodos evaluados, el método gravimétrico con detección potenciométrica presentó las mejores características metrológicas, pues se obtuvieron sesgos e incertidumbres menores.
Abstract Different measurement systems for acid-base titrations were evaluated to determine which one had the best metrological characteristics. These systems included volumetric and gravimetric titrations, which were combined with different detection systems: (i) potentiometry, (ii) acid-base indicator, and (iii) electrolytic conductivity. This article proposes a new approach for estimating the measurement uncertainty associated with the detection of the equivalence point. The results showed that, for the determination of the equivalence point, the lowest uncertainties were obtained by the potentiometric method in comparison with the conductometric method, whose bias was 78 times higher. The potentiometric method, however, was strongly dependent on the instrument resolution and/or the titrant amount that is added close to the equivalence point. It was also found that uncertainty decreases about 40% using gravimetric methods as compared to volumetric methods. When performing bias evaluation of the measurement systems according to the ISO 33:2015 guide, results showed that, among the evaluated methods, the gravimetric method with potentiometric detection presented the best metrological characteristics, with the lowest biases and uncertainties.
Resumo Foram avaliados diferentes sistemas de medida para titulações ácido-base, a fim de determinar quais possuem as melhores características metrológicas. Estes sistemas incluem titulações e gravimétricas, que foram combinadas com diferentes sistemas de detecção do ponto de equivalência: (i) potenciometria, (ii) indicador ácido-base e (iii) condutividade electrolítica. Este artigo propõe uma nova abordagem para estimar a incerteza de medição associada à detecção do ponto de equivalência. Os resultados indicaram que, para a determinação do ponto de equivalência, as incertezas mais baixas são obtidas pelo método potenciométrico enquanto que a incerteza do método condutométrico é até 78 vezes maior que a obtida pela potenciometria. Além disso, a potencimetria é altamente dependente da resolução do instrumento e/ou da quantidade de titulante para ser adicionado na proximidade com o ponto de equivalência. Também verificou-se que a incerteza diminui em torno de 40% utilizando métodos gravimétricos. De acordo à guia de norma ISO 33:2015, os resultados mostraram que os métodos de titulação ácido-base avaliados gravimetricamente com detecção potenciométrica proporcionaram as melhores características de metrologia, porque obtiveram os menores distorções e incertezas.
ABSTRACT
The construction and performance characteristics of new sensitive and selective in situ modified screen printed (ISPE) and carbon paste (ICPE) electrodes for determination of naphazoline hydrochloride (NPZ-HCl) have been developed. The electrodes under investigation show potentiometric response for NPZ-HCl in the concentration range from 7.0 ? 10-7 to 1.0 ? 10-2 M at 25 1C and the electrode response is independent of pH in the range of 3.1-7.9. These sensors have slope values of 59.770.6 and 59.270.2 mV decade?1 with detection limit values of 5.6 ? 10-7 and 5.9 ? 10-7 M NPZ-HCl using ISPE and ICPE, respectively. These electrodes show fast response time of 4-7 s and 5-8 s and exhibits lifetimes of 28 and 30 days for ISPE and ICPE, respectively. Selectivity for NPZ-HCl with respect to a number of interfering materials was also investigated. It was found that there is no interference from the investigated inorganic cations, anions, sugars and other pharmaceutical excipients. The proposed sensors were applied for the determination of NPZ-HCl in pharmaceutical formulation using the direct potentiometric method. It showed a mean average recovery of 100.2%and 102.6%for ISPE and ICPE, respectively. The obtained results using the proposed sensors were in good agreement with those obtained using the official method. The proposed sensors show significantly high selectivity, response time, accuracy, precision, limit of detection (LOD) and limit of quantification (LOQ) compared with other proposed methods.
ABSTRACT
Objective Explore the relationship of ventricular late potential (VLP) and the heart function of children with viral myocarditis,and provide the evidence for their diagnosis and therapy.Methods The clinical data of 152 cases of epileptic children were collected.The patient group was divided into three groups (severe arrhythmia,heart failure,and cardiogenic shock).The patient group was also divided into two groups (cardiac dilatation,and non-cardiac dilatation) according to UCG.Serum levels of cTnI and VLP in children with viral myocarditis were detected.Results The VLP was negative in the mild and control groups,but the positive rate of VLP is 75.0 ％ in the severe group.The positive rate of VLP was 60.0％ in the severe arrhythmia group,77.78％ in the heart failure group,and 100％ in the shock group.There is one kind of negative rank correlation between LAS,RMS40 and LVFS (P ＜ 0.05),and another negative rank correlation between RMS40 and LVEF (P ＜ 0.05).Conclusions The children with viral myocarditis have a favorable prognosis.The sever patient in the minority must be diagnosed in time and treated because of the critical state of viral myocarditis children.The serum level of cTnI and VLP were increased in children with viral myocarditis,and they were sensitive parameters to reflect patients’ condition.
ABSTRACT
O objetivo deste estudo foi o de avaliar a quantidade de Sólidos Solúveis Totais (SST) e o valor do pH em bebidas lácteas (iogurtes e achocolatados), comercializadas em Teresina e consumidas por crianças. Foram avaliadas 20 bebidas lácteas por meio do experimento casualizado com 3 repetições para cada amostra. As leituras do grau Brix foram feitas por refratometria, utilizando-se o refratômetro de Abbé, e o pH foi avaliado por potenciometria. O teor médio de SST variou de 11,0 Brix a 22,0 Brix. Com relação ao pH, os valores médios mínimo e máximo para as bebidas lácteas foram 3,79 e 6,71, respectivamente. Por meio dos resultados obtidos, pôde-se concluir que a elevada concentração de SST, verificada nas bebidas lácteas, associada a um baixo pH, pode contribuir para o desenvolvimento de lesões de cárie e erosão dental, caso esses alimentos sejam consumidos, em excesso, pelas crianças.
The main objective of this study is to proceed an evaluation of the amount of total soluble solids (TSS) and the pH value in lactic drinks (yogurt and chocolate milk) commercialized in Teresina and consumed by children. Twenty lactic drinks were evaluated in this experiment with 3 repetitions of study case in each sample. The Brix degrees measurement was made by refractometry using an Abbé refractometer and the pH was evaluated using potentiometry. The medium content of TSS was in a range between 11,0 ºBrix and 22,0 ºBrix. Meanwhile the minimum maximum pH the medium values were 3,79 and 6,71. From this results what can be concluded is that a high concentration of TSS can be verified in lactic drinks, associated with a low pH may contribute to the development of cavity lesions and dental erosion in case of the excess consumption of this products by children.
ABSTRACT
The construction and electrochemical response characteristics of polyvinyl chloride (PVC) membrane sensors for determination of bambuterol hydrochloride (BH) in presence of its degradation products are described. The sensors are based on the ion association complexes of BH cation with sodium tetraphenyl borate (BH-TPB) [sensor 1] or ammonium reineckate (BHRNC) [sensor 2] counter anions as ion exchange sites in PVC matrix. Fast and stable Nernstian responses in the range 10-5-10-2 M for BH over the pH range 5–8 revealed the performance characteristics of these electrodes, which were evaluated according to International Union of Pure and Applied Chemistry recommendations. The two proposed sensors are used for determination of BH, in pure form, in presence of its degradation product and in pharmaceutical formulations. Validation of the method according to the quality assurance standards showed suitability of the proposed electrodes for use in the quality control assessment of BH. The recoveries for determination of BH by the two proposed selective electrodes were 100.07 ± 1.008, 99.93 ± 0.920, for sensor 1 and sensor 2, respectively. Statistical comparison between the results obtained by this method and the official non-a method of BH was done, and no significant difference was found.
ABSTRACT
This paper reports on development of a system consisting of a portable sequential injector coupled with potentiometric unit for sensing of chlorpheniramine (CPA), based on the reaction of CPA with potassium permanganate in acidic media. Various experimental conditions affecting the potential intensity were studied and incorporated into the procedure. Under the optimum conditions, linear relationship between the CPA concentration and peak area was obtained for the concentration range of 0.1-50ppm. The method reflects good recovery with relative standard deviation (RSD)＜3％. The detection limit was 0.05 ppm. The developed method was successfully applied for determination of CPA in pure form and in pharmaceutical dosage forms. The results, obtained using the method, are in accord with the results of the British pharmacopoeia method. In addition to its accuracy and precision, the method has the advantages of being simple, inexpensive and rapid.
ABSTRACT
Para evaluar y comparar algunas propiedades de los ácidos húmicos (AH) y fúlvicos (AF) como el grado de condensación y polimerización, el contenido total de carbono, hidrógeno y nitrógeno, y sus constantes de acidez, se analizó la fracción menor a 50 µm de un Mollisol del horizonte Ap, bajo caña de azúcar, y se comparó con un horizonte A, bajo bosque. Para tal fin se hicieron extracciones sucesivas con tetraborato de sodio 0,05 M, pirofosfato de sodio 0,025 M e hidróxido de sodio 0,1M. Las sustancias húmicas se purificaron mediante tratamientos con ácidos inorgánicos en solución al 1% de HCl y HF, resinas de absorción Amberlita XAD-16 e intercambio catiónico R101H+, diálisis y liofilización, y se caracterizaron por análisis elemental, relación E4/E6 y potenciometría ácido-base de acuerdo con las funciones de Gran modificadas. La relación E4/E6 permitió establecer mayores tamaños moleculares y grado de condensación de los ácidos húmicos en relación con los ácidos fúlvicos. Por potenciometría ácido-base se determinaron, en los ácidos húmicos y ácidos fúlvicos, las concentraciones de grupos funcionales ácidos y sus respectivas constantes de acidez. Dos de éstas, tituladas entre pH 4,0 y 6,1 corresponden a grupos carboxílicos, las otras dos entre pH 7,2 y 8,7 son el resultado de grupos -OH fenólicos fuertes y carboxílicos débiles. En el horizonte Ap, bajo caña de azúcar, los resultados demostraron que las prácticas de uso y manejo de este cultivo han llevado a la homogeneización de las sustancias húmicas, mientras que en el horizonte A bajo bosque existen ácidos húmicos y fúlvicos diferenciados por tamaño molecular, aromaticidad y grado de humificación.
In order to determine and to compare some physicochemical properties of humic (HA) and fulvic (FA) acids such as degree of condensation and polymerization, the total C,H,N content and pKa values were analyzed in the smaller fraction (< 50 m) from Ap horizon under sugarcane crop in opposition to A horizon under forest, both Mollisol order. To carry out this aim, successive extractions with sodium tetraborate 0.05 M, sodium pyrophosphate 0.025 M, and sodium hydroxide 0.1 M were made. The purification of these humic substances by treatment with inorganic acids 1% solutions of HCl and HF, Amberlite XAD-16 adsorption resin and R 101H+ cationic exchange, dialysis and freeze driying were done. The humic and fulvic acids were characterized by elemental analysis, E4/E6 relation and acid-base potentiometry. The ratio E4/E6 allows to establish that molecular size and degree of condensation in humic acids were bigger than in fulvic acids. By means of acid-base potentiometry, the concentrations of functional acid groups and their acid constants in the humic and fulvic acids were determined. Four constants were found; first and second between pH 4.0 and 6.1 correspond to differents kinds of carboxyl groups and another two between pH 7.2 and 8.7 come from strong O-H phenolic and weak carboxyl groups. In the Ap horizon under sugarcane the characterization showed that the handling and land use practices promote the homogeneity of humic substances meanwhile in the A horizon under forest; the humic and fulvic acids are different due to their degree of condensation molecular size and humification index.
ABSTRACT
Serum consists of water (93% of serum volume) and nonaqueous components, mainly lipids and proteins (7% of serum volume). Sodium is restricted to serum water. In states of hyperproteinemia or hyperlipidemia, there is an increased mass of the nonaqueous components of serum and a concomitant decrease in the proportion of serum composed of water. Thus, pseudohyponatremia results because the flame photometry method measures sodium concentration in whole plasma. A sodium-selective electrode gives the true, physiologically pertinent sodium concentration because it measures sodium activity in serum water. Whereas the serum sample is diluted in indirect potentiometry, the sample is not diluted in direct potentiometry. Because only direct reading gives an accurate concentration, we suspect that indirect potentiometry which many hospital laboratories are now using may mislead us to confusion in interpreting the serum sodium data. However, it seems that indirect potentiometry very rarely gives us discernibly low serum sodium levels in cases with hyperproteinemia and hyperlipidemia. As long as small margins of errors are kept in mind of clinicians when serum sodium is measured from the patients with hyperproteinemia or hyperlipidemia, the present methods for measuring sodium concentration in serum by indirect sodium-selective electrode potentiometry could be maintained in the clinical practice.
Subject(s)
Humans , Electrodes , Hyperlipidemias , Laboratories, Hospital , Photometry , Plasma , Potentiometry , Sodium , WaterABSTRACT
To observe the effects of acupuncture on event related potential P3(P3) in children with attention deficit hyperactivity disorder (ADHD), P3 in 40 ADHD children and 20 normal children was detected.It was founded that the occurrence rate of P3 in ADHD chilthen under the situations of active retention and passive attenhon was 68.9% and 46.6%,and 94.3% and 35.7% in normal children respefavely(P