RESUMO
An alternative method for simultaneous baseline separation of α and ß-acids homologues and isomers in hop by CD-MEKC with UV detection was proposed. The optimized background electrolyte was composed of 30 mmol/L sodium tetraborate solution, 45 mmol/L sodium dodecyl sulfate, 20 mmol/L ß-cyclodextrin and 10% v/v acetonitrile. The instrumental conditions were evaluated by using a 33 Box-Benhken experimental design. In order to demonstrate the applicability of the method, 21 hop samples from different varieties were analyzed. The repeatability intra- and interday tests were performed and relative standard deviations lower than 7% for area and migration times were observed. The present method comprehended 8 min analysis time and revealed to be faster and more efficient when compared to previous reports from literature.
Assuntos
Ácidos/análise , Humulus/química , Boratos/química , Cromatografia Capilar Eletrocinética Micelar , Eletroforese Capilar , Isomerismo , Dodecilsulfato de Sódio/química , Espectrofotometria Ultravioleta , beta-Ciclodextrinas/químicaRESUMO
A simple and highly sensitive CE-UV method was applied in the determination of l-ctrulline, which was developed from an oral formulation for pediatric use. The novel method was based on the analysis of l-citrulline for direct ultraviolet detection at 198 nm. The BGE consisted of 10 mM sodium tetraborate and 50 mM SDS at pH 9, and the electrophoretic parameters were optimized. The method was validated in terms of specificity, linearity, LOD, LOQ, precision, accuracy, and robustness. The LOD and LOQ obtained were 1.36 and 4.54 µg/mL, respectively. In addition, the method offers higher sensitivity and specificity compared with the results obtained from HPLC method using UV-detectors, in which l-citrulline needs to be derivatizated. Furthermore, low cost and simplicity of the system allowed the rapid and simple quantitation of l-citrulline in the oral formulation for quality control and stability indicated method.
Assuntos
Citrulina/análise , Eletroforese Capilar/métodos , Soluções Farmacêuticas/análise , Espectrofotometria Ultravioleta/métodos , Cromatografia Capilar Eletrocinética Micelar , Citrulina/química , Limite de Detecção , Modelos Lineares , Soluções Farmacêuticas/química , Reprodutibilidade dos TestesRESUMO
The present work deals with the development and validation of a novel dual CD-MEKC system for the systematic flavonoid fingerprinting of Ligaria cuneifolia (R. et P.) Tiegh.-Loranthaceae-extracts. The BGE consisted of 20 mM pH 8.3 borate buffer, 50 mM SDS, a dual CD system based on the combination of 5 mM ß-CD and 2% w/v S-ß-CD, and 10% v/v methanol. The proposed method has been successfully applied to the comparative analysis of extracts from aerial parts and different hosts, geographical areas, and extraction procedures in order to establish the flavonoid fingerprint of L. cuneifolia. The method was validated according to international guidelines. LOD and LOQ, intra and interday precision, and linearity were determined for catechin, epicatechin, procyanidin B2, rutin, quercetin-3-O-glucoside, quercetin-3-O-xyloside, quercetin-3-O-rhamnoside, quercetin-3-O-arabinofuranoside, quercetin-3-O-arabinopyranoside, and quercetin. The CD-MEKC methodology emerges as a suitable alternative to the traditional HPLC for quality control, fingerprinting, and standardization of L. cuneifolia extracts from different sources.
Assuntos
Cromatografia Capilar Eletrocinética Micelar/métodos , Flavonoides/análise , Loranthaceae/química , Extratos Vegetais/química , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos TestesRESUMO
A separation method was developed in order to quantify free amino acids in passion fruit juices using CE-UV. A selective derivatization reaction with FMOC followed by MEKC analysis was chosen due to the highly interconnected mobilities of the analytes, enabling the separation of 22 amino acids by lipophilicity differences, as will be further discussed. To achieve such results, the method was optimized concerning BGE composition (concentrations, pH, and addition of organic modifier) and running conditions (temperature and applied voltage). The optimized running conditions were: a BGE composed by 60 mmol/L borate buffer at pH 10.1, 30 mmol/L SDS and 5 % methanol; running for 40 min at 23°C and 25 kV. The method was validated and applied on eight brands plus one fresh natural juice, detecting 12 amino acids. Quantification of six analytes combined with principal component analysis was capable to characterize different types of juices and showed potential to detect adulteration on industrial juices. Glutamic acid was found to be the most concentrated amino acid in all juices, exceeding 1 g/L in all samples and was also crucial for the correct classification of a natural juice, which presented a concentration of 22 g/L.
Assuntos
Aminoácidos/análise , Eletroforese Capilar/métodos , Frutas/química , Espectrofotometria Ultravioleta/métodos , Concentração de Íons de Hidrogênio , Limite de Detecção , Análise de Componente PrincipalRESUMO
A stability-indicating MEKC method was developed and validated for the simultaneous determination of aliskiren (ALI) and hydrochlorothiazide (HCTZ) in pharmaceutical formulations using ranitidine as an internal standard (IS). Optimal conditions for the separation of ALI, HCTZ and its major impurity chlorothiazide (CTZ), IS and degradation products were investigated. The method employed 47 mM Tris buffer and 47 mM anionic detergent SDS solution at pH 10.2 as the background electrolyte. MEKC method was performed on a fused-silica capillary (40 cm) at 28°C. Applied voltage was 26 kV (positive polarity) and photodiode array (PDA) detector was set at 217 nm. The method was validated in accordance with the ICH requirements. The method was linear over the concentration range of 5-100 and 60-1200 µg/mL for HCTZ and ALI, respectively (r(2) >0.9997). The stability-indicating capability of the method was established by enforced degradation studies combined with peak purity assessment using the PDA detection. Precision and accuracy evaluated by RSD were lower than 2%. The method proved to be robust by a fractional factorial design evaluation. The proposed MEKC method was successfully applied for the quantitative analysis of ALI and HCTZ both individually and in a combined dosage tablet formulation to support the quality control.