Development of a Gas-Tight Syringe Headspace GC-FID Method for the Detection of Ethanol,and a Description of the Legal and Practical Framework for Its Analysis,in Samples of English and Welsh Motorists’ Blood and Urine

Ethanol is the most commonly used recreational drug worldwide. This study describes the development and validation of a headspace gas chromatography flame ionisation detection (HS-GC-FID) method using dual columns and detectors for simultaneous separation and quantitation. The use of a dual-column, dual-detector HS-GC-FID to quantitate ethanol is a common analytical technique in forensic toxicology; however, most analytical systems utilise pressure-balance injection rather than a simplified gas-tight syringe, as per this technique. This study is the first to develop and validate a technique that meets the specifications of the United Kingdom’s requirements for road traffic toxicology testing using a Shimadzu GC-2014 gas-tight syringe. The calibration ranged from 10 to 400 mg/100 mL, with a target minimum linearity of r2 > 0.999, using tertiary butanol as the internal standard marker. The method has an expanded uncertainty at 99.73% confidence of 3.64% at 80 mg/100 mL, which is the blood alcohol limit for drink driving in England and Wales. In addition, at 200 mg%—the limit at which a custodial sentence may be imposed on the defendant—the expanded uncertainty was 1.95%. For both the 80 mg% and 200 mg% concentrations, no bias was present in the analytical method. This method displays sufficient separation for other alcohols, such as methanol, isopropanol, acetaldehyde, and acetone. The validation of this technique complies with the recommended laboratory guidelines set out by United Kingdom and Ireland Association of Forensic Toxicologists (UKIAFT), the recently issued Laboratory 51 guidelines by the United Kingdom Accreditation Service (UKAS), and the criteria set out by the California Code of Regulations (CCR), 17 CCR § 1220.1.     

Reversible Thermal Switching of Aqueous Dispersibility of Multiwalled Carbon Nanotubes

Easily reversible aqueous dispersion/precipitation of multiwalled carbon nanotubes (MWNTs) has been demonstrated using small‐molecule non‐ionic pyrene‐based surfactants, which exhibit lower critical solution temperature (LCST) phase behaviour. The MWNTs are dispersed by means of non‐covalent interactions. The dispersibility can be switched “off” (i.e., MWNTs precipitated) upon heating and switched “on” (i.e., MWNTs re‐dispersed) upon cooling and merely swirling the sample at room temperature, that is, under very mild conditions. This effect is also observed under high ionic strength conditions with NaCl in the aqueous phase.     

Quadruple-layered perovskite (CuCl)Ca2NaNb4O13

We will present the synthesis, structure and magnetic properties of a new quadruple-layered perovskite (CuCl)Ca₂NaNb₄O₁₃. Through a topotactic ion-exchange reaction with CuCl₂, the precursor RbCa₂NaNb₄O₁₃ presumably having an incoherent octahederal tliting changes into (CuCl)Ca₂NaNb₄O₁₃ with a 2a_p×2a_p×2c_p superstructure (tetragonal; a=7.73232(5) Å, c=39.2156(4) Å). The well-defined superstructure for the ion-exchanged product should be stabilized by the inserted CuCl₄O₂ octahedral layers that firmly connect with neighboring perovskite layers. Magnetic studies show the absence of long-range magnetic ordering down to 2 K despite strong in-plane interactions. Aleksandrov′s group theory and Rietveld refinement of synchrotron X-ray diffraction data suggest the structure to be of I4/mmm space group with in-phase tilting along the a and b axes, a two-tilt system (++0).     

Real time automatic detection of Orcinus orca vocalizations in a controlled environment

The use of passive acoustic observation is a useful tool in bioacoustic studies of cetaceans, such as killer whales (Orcinus orca). Such studies require the recording, detection, and classification of vocalizations of animals during long periods of time. The manual processing of the recordings is an extremely time consuming task because of the large amount of data to process. Automatic detection and classification techniques are useful to improve the processing, increase the amount of information and, as a consequence, provide information for the conservation of these species.The Orca Ocean facilities of Loro Parque in the Canary Islands, Spain, were used as an experimental platform for developing devices to perform bioacoustic studies. Detection methods with low computational complexity were tested in order to capture vocalizations of four O. orca specimens in real time. The algorithms were also tested in other scenarios in order to determine their global performance. The sensitivity to noise was also tested. The most accurate method in this study was implemented and integrated with a continuous recording system generating an event database in real time, downsizing the storage demand to 7%. This allowed the storage of all the sound events produced in about one month on a standard computer harddisk and the generation of basic statistics on vocal activity of the animals.     

Modular construction of pyrido[24]crown-8-based templates in the self-assembly of cross-linked [n]catenanes

Starting from the versatile 4-bromopyrido[24]crown-8 building block, novel ditopic and tritopic receptors have been synthesized and shown to be appropriate hosts for bis(4-formylbenzyl)ammonium hexafluorophosphate. Association constants (per binding site) for the corresponding [3]- and [4]pseudorotaxanes, assembled from these components, were determined to be 2753  M^?1 and 723  M^?1, respectively. Mechanical bond formation was attempted utilizing dynamic imine bond formation between the formyl groups of the bound dibenzylammonium threads and p-phenylenediamine.