Multi-strip MRPCs for FOPI

During the last years FOPI has developed a new ToF system as an upgrade of the existing detector based on Multi-strip Multi-gap Resistive Plate Chambers (MMRPCs). The intention is to increase the charged Kaon identification up to a laboratory momentum of 1 GeV/c and to enhance the azimuthal detector granularity. The new ToF barrel has an active area of 5 m(2) with 2400 individual strips (900 x 1.6 mm(2)) [A. Schuttauf, et al., Nucl. Phys. B 158 (2006) 52] which are read out on both sides by a custom designed electronics [M. Ciobanu, et al., IEEE Trans. Nucl. Sci. NS-54 (4) (2007) 1201; K. Koch, et al., IEEE Trans. Nucl. Sci. NS-52(3) (2005) 745]. To reach the envisaged goal a time resolution of 100 ps is needed, at a flight path of 1-1.3 m. Due to the rare production of the K- at SIS energies the efficiency of the MMRPCs has to be above 95%. We report on measurements with the detectors and electronics from the mass production line. For this purpose we used a proton beam at 2.0 and 1.25 GeV, at rates between 0.1 and 5 kHz/cm(2) to determine the timing, efficiency and rate capability of the MMRPCs

Trichloroisocyanuric acid: A convenient oxidation reagent for phase-transfer catalytic epoxidation of enones under non-aqueous conditions

Trichloroisocyanuric acid (TCCA) is a cheap, safe and readily available alternative to the commonly used hydrogen peroxide and hypochlorite for the phase-transfer catalytic epoxidation of alpha,beta-enones under non-aqueous conditions. A variety of chalcone derivatives give the corresponding epoxides with quantitative conversion and satisfactory yields in just a few hours under mild conditions. An asymmetric variant of the epoxidation can be carried out in the presence of chiral N-anthracenylmethylcinchonidine bromide catalyst giving 73-93% ees and 76-94% yields.

Orientation and alignment of reagent molecules by two-photon excitation

The expressions used for describing the angular distribution of oriented and aligned reagent molecules are derived. The algebraic forms of orientation and alignment parameters of molecules in the excited states are obtained for two-photon excitation. The reagent molecules after absorbing two-photon may produce the higher order orientation and alignment than doing one-photon. (C) 2002 Elsevier Science B.V. All rights reserved.

Controlling the orientation and alignment of reagent molecules by a polarized laser

The expressions used for controlling the alignment and orientation of reagent molecules are derived. The problem to the control of the orientation and alignment of reagent molecules by the polarization direction and propagation direction of laser is discussed.

Synthesis of covalently bonded cellulose derivative chiral stationary phases with a bifunctional reagent of 3-(triethoxysilyl)propyl isocyanate

A bifunctional reagent of 3-(triethoxysilyl)propyl isocyanate (TEPI) was initially adopted as a spacer reagent to prepare the bonded types of chiral stationary phases (CSPs) with cellulose derivatives. The silica-based CSPs were chemically prepared with non-regioselective and regioselective approaches and their chiral resolving capabilities were evaluated in terms of HPLC resolution of test enantiomers. It was observed that the chiral recognition capabilities of the non-regioselectively prepared CSPs were influenced by the amount of TEPI used. And also, the regioselectively prepared CSP generally showed a slightly higher resolution power than the non-regioselectively prepared CSP, while the non-regioselective procedures were highly advantageous to rapid preparation. In addition, chiral recognition of the prepared CSPs was affected by the properties of the used silica matrices. (C) 2003 Elsevier B.V. All rights reserved.

Determination of peptides and amino acids from wool and beer with sensitive fluorescent reagent 2-(9-carbazole)-ethyl chloroformate by reverse phase high-performance liquid chromotography and liquid chromotography mass spectrometry

A new method for the sensitive determination of amino acids and peptides using the tagging reagent 2-(9-carbazole)-ethyl chloroformate (CEOC) with fluorescence (FL) detection has been developed. Identification of derivatives was carried out by liquid chromotography mass spectrometry. The chromophore in the 2-(9-fluorenyl)-ethyl chloroformate (FMOC) reagent was replaced by carbazole, which resulted in a sensitive fluorescence lerivatizing agent CEOC. CEOC can easily and quickly label peptides and amino acids. Derivatives are stable enough to be efficiently analyzed by high-performance liquid chromatography. Studies on derivatization demonstrate excellent derivative yields over the pH range 8.8-10.0. Maximal yields close to 100% are observed with three- to fourfold molar reagent excess. Derivatives exhibit strong fluorescence and allow direct injection of the reaction mixture with no significant disturbance from the major fluorescent reagent degradation by-products, such as 2(9-carbazole)-ethanol and bis-(2-(9-carbazole)-ethyl) carbonate. In addition, the detection responses for CEOC derivatives are compared to those obtained with FMOC. The ratios AC(CEOC)/AC(FMOC) = 1.00-1.82 for fluorescence (FL) response and AC'(CEOC)/AC'(FMOC) = 1.00-1.21 for ultraviolet (UV) response are observed (here, AC and AC' are, respectively, FL and UV F response). Separation of the derivatized peptides and amino acids has been optimized on a Hypersil BDS C18 column. Excellent linear responses are observed. This method was used successfully to analyze protein hydrolysates from wool and from direct-derivatized beer. (C) 2003 Elsevier Science (USA). All rights reserved.

Analysis of amphetamines in urine with liquid-liquid extraction by capillary electrophoresis with simultaneous electrochemical and electrochemiluminescence detection

Amphetamines including methamphetamine, 3,4-methylenedioxyamphetamine and 3,4-methylenedioxymethamphetamine were separated and detected by CE using simultaneous electrochemical (EC) and electrochemiluminescence (ECL) detection (CE-EC/ ECL). Factors that influenced the separation and detection performance, such as the detection potential, the pH value and concentration of the running buffer, the separation voltage and the pH of the detection buffer, were investigated.

Toxicological effects of cinnabar in rats by NMR-based metabolic profiling of urine and serum

Cinnabar, an important traditional Chinese mineral medicine, has been widely used as a Chinese patent medicine ingredient for sedative therapy. However, the pharmaceutical and toxicological effects of cinnabar, especially in the whole organism, were subjected to few investigations. In this study, an NMR-based metabolomics approach has been applied to investigate the toxicological effects of cinnabar after intragastrical administration (dosed at 0.5, 2 and 5 g/kg body weight) on male Wistar rats.

Enantioseparation of Dioxopromethazine Hydrochloride in Urine with Liquid-Liquid Extraction by CE-ECL Detection

Capillary electrophoresis coupled with electrochemiluminescence detection was developed for the separation and determination of dioxopromethazine hydrochloride (DPZ) enantiomers. Performance parameters of the proposed method were evaluated. An improved separation of DPZ enantiomers could be achieved after adding boric acid to buffer. The enantiomers were completely separated with running buffer of 16.5 mM beta-CD in 25 mM tris-H3PO4-40 mM H3BO3 at pH 2.5. The proposed method was successfully applied to the separation and determination of DPZ enantiomers in human urine with a liquid-liquid extraction procedure.

Electrochemiluminescence detection with integrated indium tin oxide electrode on electrophoretic microchip for direct bioanalysis of lincomycin in the urine

In this article, an antibiotic, lincomycin was determined in the urine sample by microchip capillary electrophoresis (CE) with integrated indium tin oxide (ITO) working electrode based on electrochemiluminescence (ECL) detection. This microchip CE-ECL system can be used for the rapid analysis of lincomycin within 40 s. Under the optimized conditions, the linear range was obtained from 5 to 100 muM with correlation coefficient of 0.998. The limit of detection (LOD) of 3.1 muM was obtained for lincomycin in the standard solution. We also applied this method to analyzing lincomycin in the urine matrix. The limit of detection of 9.0 muM was obtained. This method can determine lincomycin in the urine sample without pretreatment, which demonstrated that it is a promising method of detection of lincomycin in clinical and pharmaceutical area.

Determination of reserpine in urine by capillary electrophoresis with electrochemiluminescence detection

A fast and sensitive approach to detect reserpine in urine using micellar electrokinetic capillary chromatography with electrochemiluminescence (ECL) of Ru(bpy)(3)(2+) detection is described. Using a 25 mum i.d. capillary as separation column, the ECL detector was coupled to the capillary in the absence of an electric field decoupler. Field-amplified injection was used to minimize the effect of ionic strength in the sample and to achieve high sensitivity. In this way, the sample was analyzed directly without any pretreatment. The method was validated for reserpine in the urine over the range of 1 x 10(-6) - 1 x 10(-4) mol/L with a correlation coefficient of 0.996. The RSD for reserpine at a level of 5 mumol/L was 4.3%. The LOD (S/N = 3) was estimated to be 7.0 x 10(-8) mol/L. The average recoveries for 10 mumol/L reserpine spiked in human urine were 94%.

Reagent-controlled asymmetric iodolactonization using cinchona alkaloids as chiral sources

A novel method for reagent-controlled asymmetric iodolactonization of 5-aryl-4-pentenoic acids is reported. This work uses carboxylate ion pairs combined with cinchona alkaloids as chiral sources of carboxylate anion for the first time leading to a mixture of two regio-isomeric iodolactones with moderate enantioselectivity (exo- 18.5% ee, endo-35.0% ee) under mild reaction conditions.