Double dispersant‐assisted ionic liquid dispersive liquid–liquid microextraction coupled with capillary electrophoresis for the determination of benzophenone‐type ultraviolet filters in sunscreen cosmetic product

In this work, double dispersant‐assisted ionic liquid dispersive liquid–liquid microextraction coupled with micellar electrokinetic chromatography was developed to determine four UV filters (benzophenone, 4‐hydroxybenzophenone, 2,4‐dihydroxybenzophenone, and 2‐hydroxy‐4‐methoxybenzophenone). 1‐Hexyl‐3‐methylimidazolium hexafluorophosphate was used as the extraction solvent. The main novelty of the present work was that acetonitrile‐Triton X‐114 was used as double disperser solvent. Parameters affected the extraction efficiency were investigated and optimized. Under the optimum conditions, enrichment factors were in the range of 25.3?40.5. The limits of detection and quantitation, calculated at a S/N of three and ten, were 3.9?6.7 ng/mL and 13.0?22.3 ng/mL. The linearity of the method was in the range of 0.02?2 μg/mL for 2, 4‐dihydroxybenzophenone and 4‐hydroxybenzophenone, 0.01?2 μg/mL for benzophenone and 2‐hydroxy‐4‐methoxybenzophenone, with correlation coefficient (R²) of 0.9984?0.9991. The proposed method was successfully applied to the determination of four benzophenone‐type UV filters in six kinds of sunscreen cosmetic products, with yielded relative recoveries ranging from 80.2 to 117.7%.     

Microwave‐Assisted Xanthone Synthesis

Xanthones have been prepared by microwave irradiation–assisted cyclization of 2‐hydroxy‐2′‐methoxy benzophenone precursors in a short time and good yields.     

Determination of benzophenones in human placental tissue samples by liquid chromatography-tandem mass spectrometry

Benzophenones (BPs) are a family of compounds widely used to protect the skin and hair from UV irradiation. Despite human exposure to BPs through dermal application of products containing sunscreen agents and the increasing evidence that BPs are able to interfere with endocrine systems, few studies have examined the occurrence of BPs in humans. In this work, we propose a new liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to determine six BPs, namely, benzophenone-1 (BP-1), benzophenone-2 (BP-2), benzophenone-3 (BP-3), benzophenone-6 (BP-6), benzophenone-8 (BP-8) and 4-hydroxybenzophenone (4-OH-BP) in human placental tissue samples. The method involves an extraction step of the analytes from the samples using ethyl acetate, followed by a clean-up step using centrifugation prior to their quantification by LC-MS/MS using an atmospheric pressure chemical ionization (APCI) interface in the positive mode. Benzophenone-d₁₀ (BP-d₁₀) was used as surrogate. Found detection limits (LOD) ranged from 0.07 to 0.3 ng g⁻¹ and quantification limits (LOQ) from 0.3 to 1.0 ng g⁻¹, while inter- and intra-day variability was under 5%. The method was validated using standard addition calibration and a recovery assay. Recovery rates for spiked samples ranged from 98 to 104%. This method was satisfactorily applied for the determination of BPs in 16 placental tissue samples collected from women who live in Granada (Spain).     

A New Monoterpene Glucoside from the Roots of Paeonia lactiflora

A new monoterpene glucoside, 1‐O‐β‐D ‐glucopyranosyl‐8‐O‐benzoylpaeonisuffrone ( 1 ), was isolated from the roots of Paeonia lactiflora cultivated in Korea, together with two known compounds 1‐O‐β‐D ‐glucopyranosylpaeonisuffrone and paeonidanin ( 2 ). Their structures were established on the basis of chemical and spectroscopic methods.     

Visible light photocatalysis with benzophenone for radical thiol-ene reactions

We report herein a simple, metal- and oxidant-free visible light promoted strategy for an anti-Markovnikov hydrothiolation of unactivated olefins using benzophenone as an inexpensive photocatalyst at room temperature. Anti-Markovnikov adducts of a wide variety of olefins and thiols are formed in highly regioselective manner and good to excellent yields. The present radical thiol-ene reaction is operationally simple and well tolerates a variety of functional groups.     

New Oligosaccharide Esters and Xanthone C‐Glucosides from Polygala telephioides

Three new oligosaccharide esters named telephioses D ( 4 ), E ( 5 ), and F ( 6 ), and two new xanthone C‐glucosides, telephioxanthones A ( 7 ) and B ( 8 ), together with five known oligosaccharide esters and mangiferin, were isolated from the whole plant of Polygala telephioides Willd . The structures of the new compounds were elucidated on the basis of spectral data.     

A New Compound from Dalbergia odorifera T. Chen

The plant Dalbergia odorifera T. Chen (Leguminosae) is a high tree, the root and heartwood of this plant is a Chinese traditional medicine named Jiangxiang. It is indigenous to Guangdong province.Compound 1 was isolated from the EtOAc extract of plant Dalbergia odorifera T. Chen as yellow crystalline powder, mp: 191.2-192.5 ℃. EI-MS (m/z): 244 (96), 243 (92), 167 (100), 166 (65), 123 (23), 105 (55), 77 (95). IR ν(KBr) cm-1 : 3300 (hydryoxy), 1637 (β-unsaturated carbonyl), 1597, 1571…     

Determination of Copper by Atomic Absorption Spectrophotometry After Solid-Liquid Separation by Adsorption of its 1-Nitroso-2-Naphthol Complex onto Microcrystalline Benzophenone

ABSTRACT

A sensitive method for the determination of trace copper by preconcentration and adsorption of its 1-nitroso-2-naphthol complex onto the microcrystalline benzophenone has been developed. Several experimental conditions such as the pH of the solution, the quantities of 1-nitroso-2-naphthol and benzophenone, and the stirring time were optimized for effective separation. Trace copper in a 100 ml water sample was chelated with 2.0 ml of 0.050 M 1-nitroso-2-naphthol at pH 8.0. The solution was heated to 30 °C, stirred vigorously for 10 minutes to adsorb the copper complex quantitatively onto 0.20 g benzophenone. After the microcrystalline benzophenone adsorbed copper complex was filtered and dissolved in acetone, the content of copper was determined by flame atomic absorption spectrophotometry. The interfering effects of concomitant ions were investigated and almost eliminated. The detection limit and the determination limit of this method were 6.9 ngml^?1 and 22.9 ngml^?1, respectively. Recoveries of 103.7 % and 94.2 % were obtained in a tap water and a brass sample, respectively. In the determination of copper in real samples, the values obtained by this proposed method were close to those by GF-AAS.

Based on these experimental results, it is supposed that this method can be applied to the determination of copper in real samples.     

Efficient Liquid‐Phase Oxidation of Diphenylmethane to Benzophenone over Vanadium‐Containing MCM‐41 Catalysts

The liquid‐phase oxidation of diphenylmethane with tert‐butylhydroperoxide has been studied using vanadium‐containing MCM‐41 materials, which were prepared by direct hydrothermal (V‐MCM‐41) and wet impregnation (V/MCM‐41) methods. These catalysts were characterized in detail by ICP‐AES, N₂‐sorption, XRD, FT‐IR, ²⁹Si and ⁵¹V NMR, TPD of ammonia, TPR of hydrogen, and chemisorption of oxygen. Both series of catalyst show good catalytic results, which are attributed to their highly ordered mesoporous structure, large BET surface area as well as the presence of easily accessible vanadium‐oxygen species as active centers in the catalyst. Further, V‐MCM‐41 exhibit superior catalytic activity (based on turnover number) than V/MCM‐41 mainly due to well‐dispersed tetrahedral vanadium‐oxygen species with higher oxidation ability. The effect of reaction parameters, i.e., temperature, time, solvent, etc. were investigated. Catalyst recycling test reveals good stability with only slight extent of leaching during the reaction.