ABSTRACT
An analytical method based on capillary electrophoresis (CE) with a partially aqueous electrolyte system was developed to enable the free fatty acids of Brazil nut oil to be identified in cosmetic formulations. In this study, a gel cream formulation was developed and its oil phase was extracted with a mixture of chloroform-methanol-water (1:2:0.8 v/v/v). The chloroform layer was saponified with a methanolic solution of NaOH (0.5 mol L-1) at 75-80 °C for 25 minutes. Experiments were carried out on a Beckman PACE/MDQ CE system (Fullerton, CA, USA) equipped with an on-column, diode-array detection system set at 254 nm and at 25ºC. The electrolyte consisted of 12.5 mmol L-1 sodium tetraborate buffer pH 7.0, 12.5 mmol L-1 polyoxyethylene 23-lauryl ether, 7.5 mmol L-1 sodium dodecylbenzenesulfonate (used as chromophore for indirect UV detection) and acetonitrile (35% v/v). The proposed method allowed the separation and identification of the fatty acids of Brazil nut oil in a cosmetic gel cream, as well as enabling possible interference by the oily phase components in the formulation to be identified.
Um método de análise por eletroforese capilar com sistema de eletrólito parcialmente aquoso foi desenvolvido para identificar os ácidos graxos livres do óleo de Castanha do Brasil em formulações cosméticas. No presente trabalho foi desenvolvida uma formulação cosmética (gel creme) cuja fase oleosa foi extraída com uma mistura de clorofórmio-metanol-água (1:2:0.8 v/v/v). A camada de clorofórmio, foi saponificada com solução de NaOH em metanol (0,5 mol L-1) a 75-80 °C durante 25 minutos. Os experimentos foram realizados em sistema de eletroforese capilar Beckman PACE/MDQ (Fullerton, CA, USA), com detecção de arranjo de diodos a 254 nm e a 25 ºC. O eletrólito utilizado foi 12,5 mmol L-1 de tetraborato de sódio tampão a pH 7,0, 12,5 mmol L-1 de éter de polioxietileno 23-lauril, 7,5 mmol L-1 de dodecilbenzenosulfonato de sódio (utilizado como agente cromóforo para detecção UV indireta) e acetonitrila (35% v/v). O método proposto permitiu a separação e a identificação dos ácidos graxos do óleo de Castanha do Brasil em formulações cosméticas, bem como possibilitou a identificação de interferências presentes na fase oleosa da formulação.
Subject(s)
Cosmetics , Electrophoresis, Capillary , Fatty AcidsABSTRACT
A rapid HPLC method was developed for the assay of tocopheryl acetate and ascorbyl tetraisopalmitate in cosmetic formulations. The validated method was applied for quantitative determination of these vitamins in simulated emulsion formulation. Samples were analysed directly on a RP-18 reverse phase column with UV detection at 222 nm. A mixture of methanol and isopropanol (25 : 75 v/v) was used as mobile phase. The retention time of tocopheryl acetate and ascorbyl tetraisopalmitate were 3.0 min and 5.9 min, respectively. Recovery was between 95% and 104%. In addition, the excipients did not interfere in the analysis. The method is simple, reproducible, selective and is suitable for routine analyses of commercial products.
Subject(s)
Antioxidants/analysis , Ascorbic Acid/analogs & derivatives , Cosmetics/chemistry , Tocopherols/analysis , Ascorbic Acid/analysis , Chromatography, High Pressure Liquid/methodsABSTRACT
The aim of this research was to develop and validate a high-performance liquid chromatographic (HPLC) method for simultaneous determination of five sunscreens, namely benzophenone-3 (B-3), butyl methoxydibenzoylmethane (BM), octyl methoxycinnamate (OM), octyl salicylate (OS) and homosalate (HS). The separation and quantitative determination was made by HPLC at 40 +/-1 degrees C with a gradient elution from 10% to 100% mobile phase B in mobile phase A. The gradient liquid chromatographic system constituted of mobile phase A [acetonitrile : water (10 : 90 v/v)] and mobile phase B [acetonitrile : water (90 : 10 v/v)], at a flow rate of 1.0 mL min(-1) and ultraviolet detection at 310 nm. The separation was obtained with two Waters reversed phase columns: Novapack C-18 and Symmetry((R)) C-18 connected in series. All sunscreens were efficiently separated within 17 min. The coefficient of correlation and average recovery for B-3, BM, OM, OS and HS were 0.9798 and 98.5%, 0.9672 and 98.8%, 0.9922 and 99.1%, 0.9961 and 98.9% and 0.9909 and 99.4% respectively. The relative standard deviations obtained were between 1.07% and 2.44%. The excipients did not interfere in the analysis. The results showed that the proposed method could be used for rapid and simultaneous determination of B-3, BM, OM, OS and HS in sunscreen lotions with precision, accuracy and specificity.
ABSTRACT
The aim of this research was the development and validation of a high performance liquid chromatography (HPLC) method for the simultaneous and quantitative determination of benzophenone-3, octyl methoxycinnamate and octyl salicylate contained in sunscreen emulsions. The separation and quantitative determination was achieved using a LiChrospher((R)) 100 RP-18 (5 microm) Merck column, a mobile phase constituted of methanol/water (85/15, v/v), a flow-rate of 1.0 mL min(-1) and UV detection at 310 nm. The correlation coefficients and percentage of recovery for benzophenone-3, octyl methoxycinnamate and octyl salicylate were 0.9999 and 99.46%; 0.9995 and 98.85%; 0.9998 and 98.84%, respectively. The relative standard deviations (RSD) for commercial samples were between 0.50 and 0.70%.
