Rapid Analysis of Ingredients in Cream Using Ultrasonic Mist–Direct Analysis in Real-Time Time-of-Flight Mass Spectrometry

A novel method for the simultaneous detection of ingredients in pharmaceutical applications such as creams and lotions was developed. An ultrasonic atomizer has been used to produce a mist containing ingredients. The analyte molecules in the mist can be ionized by using direct analysis in real time (DART) at lower temperature than traditionally used, and we thus solved the problem of normal DART-MS measurement using a high-temperature gas. Thereby, molecular-related ions of heat-unstable components and nonvolatile components became detectable. The deprotonated molecular ion of glycyrrhizic acid (m/z 821), which is unstable at high temperatures, was detected without pyrolysis by ultrasonic mist–DART-MS using unheated helium gas, although it was not detected by normal DART-MS using heated helium gas. The cationized molecular ions of derivatives of polyethylene glycol fatty acid monoesters, which are nonvolatile compounds, were also detected as m/z peaks observed from 800 to 2300. Although the protonated molecular ion of tocopherol acetate was not detected in ionization by ultrasonic mist, it was detected by ultrasonic mist–DART-MS even in the emulsion. It was not necessary to dissolve a sample completely to detect its ions. This method enabled us to obtain the composition of pharmaceutical applications simply and rapidly.

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Electrochemically Mediated Atom Transfer Radical Polymerization from a Substrate Surface Manipulated by Bipolar Electrolysis: Fabrication of Gradient and Patterned Polymer Brushes

We report the first ever use of electrochemically mediated atom transfer radical polymerization (eATRP) employing a bipolar electrochemical method for the fabrication of both gradient and patterned polymer brushes. A potential gradient generated on a bipolar electrode allowed the formation of a concentration gradient of a Cu^I polymerization catalyst through the one‐electron reduction of Cu^II, resulting in the gradient growth of poly(NIPAM) brushes from an initiator‐modified substrate surface set close to a bipolar electrode. These polymer brushes could be fabricated in three‐dimensional gradient shapes with control over thickness, steepness, and modified area by varying the electrolytic conditions. Moreover, by site‐selective application of potential during bipolar electrolysis, a polymer brush with a circular pattern was successfully formed. Polymerization was achieved using both a polar monomer (NIPAM) and a nonpolar monomer (MMA) with the eATRP system.     

Synthesis of biaryl compounds using tandem ruthenium-catalyzed ring-closing metathesis

Tandem ring-closing enyne metathesis (RCEM)/ring-closing olefin metathesis (RCM) of tetraenynes with Grubbs second-generation catalyst, followed by elimination, was found to be a new and efficient synthetic approach to biaryl compounds. A preliminary asymmetric version of this approach, which used homochiral Ru-alkylidene catalysts, is also presented.     

On indices of local rings along local homomorphisms

Let φ:R → Sbe a local homomorphism of Gorenstein local rings of finite flat dimension. We prove if M is a stable maximal Cohen-Macaulay R-module, then M ?_R Sis also a stable maximal Cohen-Macaulay S-module. By using it, we also prove that index(R) ≤ index(S).     

A chemical study of thermally activated chromic titanate on silica ethylene polymerization catalysts

Thermally activated ethylene polymerization catalysts which contain chromium and titanium on silica differ from those catalysts which contain only chromium on silica. The characteristics of chromium-titanium catalysts vary with the method of incorporating the titanium and the thermal activation procedure. Titanated catalysts of the kind examined in this article have faster initiation and a higher polymerization rate per unit catalyst weight than corresponding catalysts without titanium. High-density polyethylene produced by this type of titanium-chromium catalyst tends to have a higher melt index and a broader molecular weight distribution than polyethylene made with chromium on silica catalysts. Iodometric titration showed that reduction from the initial hexavalent chromium to trivalent occurs when the dry, catalyst starting material is treated with titanium tetraisopropoxide. A study of the reaction between chromium trioxide and titanium tetraisopropoxide in carbon tetrachloride revealed that (1) it is not necessary to have a reaction between surface silanols and titanium tetraisopropoxide for the reduction to occur, and (2) the reaction product has an absorption near 660 nm in the visible range. Comparison of spectra showed that chromium trioxide on silica reduced by isopropyl alcohol has a shifted absorption, i.e., 600 nm. These findings are interpreted to mean that titanium atoms come sufficiently close to chromium atoms to change their electron density in the starting material and remain close neighbors in the activated catalysts. The interpretation is further supported by ESCA data and leads to the proposal that in this case the activated catalysts contain titanium chromate structures.     

Lissoclibadins 1-3, three new polysulfur alkaloids, from the ascidian Lissoclinum cf. badium

Three new polysulfur alkaloids, lissoclibadins 1 (1)-3 (3), were isolated from the ascidian Lissoclinum sp. (cf. L. badium Monniot, F. and Monniot, C., 1996). The structures of 1-3 were assigned on the basis of their spectral data, and the computational modeling study was utilized for 1. Compound 1 had a trimeric structure of three identical aromatic anime moieties connected through two sulfide and a disulfide bonds. Compounds 2 and 3 were dimeric structures of the same unit as that of 1 connected through a sulfide and disulfide bonds (2) and two sulfide bonds (3). Compounds 1 and 2 inhibited the growth of the marine bacterium Ruegeria atlantica (15.2 mm at 20 μg/disk and 12.2 mm at 5 μg/disk, respectively) and 2 showed antifungal activity to Mucor hiemalis (13.8 mm at 50 μg/disk). Compounds 1-3 were cytotoxic against HL-60 (IC₅₀=0.37, 0.21, and 5.5 μM, respectively).     

A Novel Thermomorphic System for Electrocatalytic Diels‐Alder Reactions

The discovery that lithium bis(trifluoromethane)sulfonamide (LiTFSI)/1‐nitropropane (PrNO₂) solution functions as a less polar alternative to lithium perchlorate (LiClO₄)/nitromethane (MeNO₂) solution has led to the development of a novel thermomorphic system for electrocatalytic Diels‐Alder reactions. Methyl cyclohexane (Me‐c‐Hex) can form a monophasic condition with LiTFSI/PrNO₂ solution at room temperature, enabling the use of hydrophobic dienophiles. After the electrochemical reaction, a biphasic condition can be formed at –50°C, where the cycloadducts are selectively recovered from the upper Me‐c‐Hex phase and the remaining lower LiTFSI/PrNO₂ solution can be reused.     

Determination of trace phosphate ion in water by visual method after preconcentration on a membrane filter for field work

A sensitive visual method based on comparing the color intensity of precipitate as phosphomolybdenum blue on a membrane filter, has been developed for the determination of trace phosphate ion in water for field work. A sample solution containing 0.05-5.0 mug of phosphate was treated in a 25-ml polypropylene syringe, and the resulting precipitate was filtered through a membrane filter attached to the syringe. The color intensity of the precipitate on the membrane filter was measured visually following the standard series method. The coefficient of variation for five measurements at 0.5 mug of phosphate is 11%. The detection limit is 0.02 mug of phosphate ion in 22.5 ml (0.9 mug PO(3-)(4)/l) of water sample when the effective filtration area is 0.78 cm(2). The interference of various ions was studied and optimum conditions were developed for the determination of phosphate ion in natural water.     

Evolution of water vapor from indium-tin-oxide thin films fabricated by various deposition processes

Tin-doped In₂O₃ (indium-tin-oxide) transparent conducting films are widely used as electrodes of liquid crystal displays and low-E windows. In the present study, a systematic TDS study was undertaken for ITO films fabricated by various deposition processes; such as PVD, dip coating and spray deposition. Water vapor was the main gas evolved from the films; gas evolution from the silicon substrate was negligible. The evolution proceeded via two steps at approximately 373 and 473-623 K. The amount of the evolved water was in the order: (dip-coated film)>(PVD films)> (spray-deposited film). This order was identical to that of the film's resistivities. This revised version was published online in August 2006 with corrections to the Cover Date.