Cloud point extraction combined with micellar electrokinetic capillary chromatography determination of benzophenones in cosmetic matrix

Abstract

A method has been developed for the separation and determination of three hydrophobic benzophenones: 2,4-dihydroxybenzophenone (BP-1), 2,2'4,4'-tetrahydroxybenzophenone (BP-2), and 2-hydroxy-4-methoxybenzophenone (BP-3) in sunscreen by micellar electrokinetic capillary chromatography (MEKC) combined with cloud point extraction (CPE). The analytes were extracted at pH 5.0 by micelles of the nonionic surfactant polyoxyethylene-7.5-octylphenyl ether (Triton X-114). A 150 microL aliquot from the extracted surfactant-rich phase was diluted up to 500 microL with ethanol to reduce its viscosity before separation by MEKC. A background electrolyte of 25 mmol/L sodium tetraborate containing 30 mmol/L sodium dodecyl sulfate at pH 9.25 was used as the separation medium to avoid the adsorption of hydrophobic substances and Triton X-114 onto the inner surface of the separation capillary, ensuring the separation efficiency and reproducibility. Detection is performed at 290 nm. Under the optimized conditions, an enrichment factor of 20 was obtained and the determination limits of BP-1, BP-2, and BP-3 were found to be 3.90 x 10(-) (7), 3.83 x 10(-7), and 6.42 x 10(-8) mol/L, respectively. In comparison with the earlier reported methods, the LODs of this method are superior to the other methods. The presented procedure was successfully applied to the determination of BP-1, BP-2, and BP-3 in sunscreen with satisfactory results.

Determination of Three Phthalate Esters in Environmental Samples by Coal Cinder Extraction and Cyclodextrin Modified Micellar Electrokinetic Chromatography

“…Nevertheless, despite its advantages, the low concentration sensitivity (because of a short optical path length) and a small injection volume (several nanoliters) make it difficult to meet the requirements for trace analysis in real samples. Therefore, a sample pretreatment procedure, such as cloud point extraction (22), liquid-phase microextraction (23), solidphase extraction (SPE) (24,25), or solid-phase microextraction (26) usually has to be conducted before analysis.…”

Solid-phase extraction and field-amplified sample injection–capillary zone electrophoresis for the analysis of benzophenone UV filters in environmental water samples

“…Lately, the use of capillary electrophoresis (CE) techniques has increased as an alternative to LC because of its high efficiency, rapid analysis, and low reagent consumption, and several applications dealing with the analysis of UV-filters in cosmetics are described in the literature [5,[18][19][20][21]. To the best of our knowledge, there is only one publication in the literature describing the use of a capillary electrophoresismass spectrometry (CE-MS) method for the analysis of several UV-filters, including some BPs, in river water samples [22].…”

Preliminary results from an analog implementation of first‐order TDCNN dynamics

“…The CE instrument (Beijing Cailu Scientific Instrument, China) with a UV detector for absorbance measurements used in this work was identical with that reported previously 25. A fused‐silica capillary tubing of 51 cm (43 cm to the detector, 75 μm id×375 μm od) with a polyimide outer coating was purchased from Yongnian Optical Fiber, Hebei, China.…”