Preparative isolation of (+)-beta-eudesmol fromAmyris balsamifera

Summary Optically pure (+)-beta-eudesmol is a possible starting material for the synthesis of several termite defense compounds. A two step procedure for the isolation of gram quantities of (+)-beta-eudesmol from commercially availableAmyris balsamifera oil (syn. West Indian sandalwood oil), containing 8% beta-eudesmol, was developed. Step one consisted of an efficient vacuum distillation of the total oil. Step two was a medium pressure LC separation with an AgNO₃ impregnated silica gel stationary phase. Several other separation procedures failed due to the presence of many closely related sesquiterpene alcohols (75% of the oil).     

Mössbauer characterization of iron and cobalt dinitrosyl derivatives of 1,1′-bis(diphenylphosphino)ferrocene

The interest in the synthesis and reactivity of organometallic compounds which have two or more different metals in the same molecule has grown in recent years, due to the new chemical properties that they can present. In this work, we report the Mössbauer characterization of dppfFe(CO)₃ and two novel compounds, dppfFe(NO)₂ and [dppfCo(NO)₂]⁺[SbF₆]^–, where dppf =1,1-bis(diphenylphosphino)ferrocene. The complexes were also characterized by IR and³¹P NMR. The Mössbauer parameters of the dppfFe(NO)₂ and dppfFe(CO)₃, show two iron sites in the same proportions while for [dppfCo(NO)₂ ⁺[SbF₆]^– only one site was observed.     

Non-destructive method for determination of hydroxyl value of soybean polyol by LS-SVM using HATR/FT-IR

This paper presents the use of least-squares support vector machine (LS-SVM) for quantitative determination of hydroxyl value (OHV) of hydroxylated soybean oils by horizontal attenuated total reflection Fourier transform infrared (HATR/FT-IR) spectroscopy. A least-squares support vector machine (LS-SVM) calibration model for the prediction of hydroxyl value (OHV) was developed using the range 1805.1-649.9 cm(-1). Validation of the method was carried out by comparing the OHV of a series of hydroxylated soybean oil predicted by the LS-SVM model to the values obtained by the AOCS standard method. A correlation coefficient equal to 0.989 and RMSEP = 4.96 mg of KOH/g was obtained. This study demonstrates a better prediction ability of the LS-SVM technique to determine OHV in hydroxylated soybean oil samples by HATR/FT-IR spectra.     

Investigations into beam monitors at the AEg ̄ IS experiment

Detailed diagnostic of antiproton beams at low energies is required for essentially all experiments at the Antiproton Decelerator (AD), but will be particularly important for the future Extra Low ENergy Antiproton ring (ELENA) and its keV beam lines to the different experiments. Many monitors have been successfully developed and operated at the AD, but in particular beam profile monitoring remains a challenge. A dedicated beam instrumentation and detector test stand has recently been setup at the AE \(\bar {g}\) IS experiment (Antimatter Experiment: Gravity, Interferometry, Spectroscopy). Located behind the actual experiment, it allows for parasitic use of the antiproton beam at different energies for testing and calibration. With the aim to explore and validate different candidate technologies for future low energy beam lines, as well as the downstream antihydrogen detector in AE \(\bar {g}\) IS, measurements have been carried out using Silicon strip and pixel detectors, a purpose-built secondary emission monitor and emulsions. Here, results from measurements and characterization of the different detector types with regard to their future use at the AD complex are presented.     

Very efficient epoxidation of 1,4‐polybutadiene with the biphasic system methyltrioxorhenium (MTO)‐CH2Cl2/H2O2

The biphasic system methyltrioxorhenium (MTO)‐H₂O₂/CH₂Cl₂ was studied in the epoxidation of polybutadiene and the results showed that this system presents a high selectivity and the extension of epoxidation (10–50%) can be modulated by the amount of oxidant added, without significant change in the molecular weight of the polymer.     

Determination of cannabinoids in plasma using salting-out-assisted liquid–liquid extraction followed by LC–MS/MS analysis

The detection of the markers of Cannabis consumption in biological specimens is an important task for drug testing laboratories in varous contexts. A simple assay combining salting-out assisted liquid–liquid extraction sample preparation and LC–MS/MS analysis was applied to the measurement of Δ⁹-tetrahydrocannabinol, 11-nor-9-carboxy-Δ⁹-tetrahydrocannabinol (THC-COOH), 11-hydroxy-Δ⁹-tetrahydrocannabinol, cannabinol and cannabidiol concentrations in 100 μl plasma specimens. The assay had linearity of 1–100 ng ml⁻¹ for THC-COOH and 0.5–50 ng ml⁻¹ for the other tested cannabinoids. Assay validation criteria were fulfilled. Extraction yields (88.7–97.3%) and internal-standard correct matrix effects (−9.6 to +5.4%) were acceptable. The assay was applied to 238 clinical specimens from trauma patients, with 19 samples presenting quantifiable concentrations of at least one of the target compounds. The developed assay is a simple and efficient strategy for simultaneous measurement of Δ⁹-tetrahydrocannabinol, THC-COOH, 11-hydroxy-Δ⁹-tetrahydrocannabinol, cannabinol and cannabidiol concentrations in plasma specimens.