Positional isomer differentiation of synthetic cannabinoid JWH‐081 by GC‐MS/MS

Like many new designer drugs of abuse, synthetic cannabinoids (SC) have structural or positional isomers which may or may not all be regulated under law. Differences in acute toxicity may exist between isomers which impose further burden in the fields of forensic toxicology, medicine and legislation. Isomer differentiation therefore becomes crucial from these standpoints as new designer drugs continuously emerge with just minor positional modifications to their preexisting analogs. The aim of this study was to differentiate the positional isomers of JWH‐081. Purchased standard compounds of JWH‐081 and its positional isomers were analyzed by gas chromatography‐electron ionization‐mass spectrometry (GC‐EI‐MS) first in scan mode to investigate those isomers who could be differentiated by EI scan spectra. Isomers with identical or near‐identical EI spectra were further subjected to GC‐tandem mass spectrometry (MS/MS) analysis with appropriate precursor ions. EI scan was able to distinguish 3 of the 7 isomers: 2‐methoxy, 7‐methoxy and 8‐methoxy. The remaining isomers exhibited near‐identical spectra; hence, MS/MS was performed by selecting m/z 185 and 157 as precursor ions. 3‐Methoxy and 5‐methoxy isomers produced characteristic product ions that enabled the differentiation between them. Product ion spectrum of 6‐methoxy isomer resembled that of JWH‐081; however, the relative ion intensities were clearly different from one another. The combination of EI scan and MS/MS allowed for the regioisomeric differentiation of the targeted compounds in this study. Copyright © 2015 John Wiley & Sons, Ltd.     

Coordination-network-based ionic plastic crystal for anhydrous proton conductivity

An ionic coordination network consisting of protonated imidazole and anionic one-dimensional chains of Zn(2+) phosphate was synthesized. The compound possesses highly mobile ions in the crystal lattice and behaves as an ionic plastic crystal. The dynamic behavior provides a proton conductivity of 2.6 × 10(-4) S cm(-1) at 130 °C without humidity.     

Post-Metalation Modification of a Macrocyclic Dicobalt(III) Metallohost by Site-Selective Ligand Exchange for Guest Recognition Control

We propose post-metalation modification as a useful strategy to control the guest recognition behavior of a metal-containing macrocyclic host. This is based on the ligand exchange of the axial ligands of a cobalt(III) dinuclear macrocyclic host, [LCo₂X₄]²⁺ (X=axial amine ligand). Four piperidine ligands in [LCo₂(pip)₄]²⁺ (pip=piperidine) were site-selectively replaced with primary amines. The competitive experiments revealed that the order of the affinity toward the cobalt centers in [LCo₂X₄]²⁺ is primary amine > secondary amine > tertiary amine and that the piperidine-coordinating complex, [LCo₂(pip)₄]²⁺, was reasonably reactive among the isolable complexes. Indeed, two piperidine ligands at the diagonal positions in [LCo₂(pip)₄]²⁺ were site-selectively replaced with pyridine or acetate ion. The replacement of piperidine with acetate ion significantly enhanced the recognition ability towards Na⁺.     

Piezoelectric relaxations in polymers: Spherical dispersion model

For the interpretation of piezoelectric relaxation in oriented polymers, a spherical dispersion model is proposed in which piezoelectric spheres are dispersed in a nonpiezoelectric medium. The influence of the dielectric and elastic relaxations in the medium and the sphere on the piezoelectric stress constant and strain-constant is analyzed in detail. The origins of piezoelectric relaxations in oriented poly-γ-methyl-L-glutamate are assigned to the elastic relaxation (at about ?70°) and the dielectric relaxation (at about 0°C) in the piezoelectric phase, and the elastic relaxation (at about 100°C) in the non-piezoelectric phase, respectively.     

Regioselective photoallylations of dicyanopolycyclic aromatic compounds via electron transfer

Upon irradiation with allyltrimethylsilane, dicyanopolycyclic aromatic compounds undergo two modes of photoallylations, depending on the compounds and the reaction conditions. Both the photoreactions occur in a highly regioselective manner via electron transfer.     

Laser photolysis of silver colloid prepared by citric acid reduction method

By irradiating a silver colloid, prepared via the citric reduction method, using the second harmonic of a Nd:YAG laser, lambda = 532 nm, with laser fluence more than about 0.2 J/cm(2), we prepared a colloid consisting of small spherical silver nanoparticles with d(p) = 8 nm. The process of particle formation can be divided into three steps. First, large particles that existed in the initial colloid evaporate fully, producing a large amount of silver atoms. Next, primary particles with d(p) = 2-4 nm are formed in mini plumes. Finally, these primary particles grow up to 8 nm, as silver atoms diffuse to them through water.     

The effect of dissipation on quantum transmission resonance

Quantum transmissions of a free particle passing through a rectangular potential barrier with dissipation are studied using a path decomposition technique. Dissipative processes strongly suppress the transmission probability at resonance just above the barrier resulting in an unexpected reduction of the mean traversal time through the potential barrier.     

Discrimination and identification of the six aromatic positional isomers of trimethoxyamphetamine (TMA) by gas chromatography-mass spectrometry (GC-MS)

A reliable and accurate GC-MS method was developed that allows both mass spectrometric and chromatographic discrimination of the six aromatic positional isomers of trimethoxyamphetamine (TMA). Regardless of the trifluoroacetyl (TFA) derivatization, chromatographic separation of all the investigated isomers was achieved by using DB-5 ms capillary columns (30 m x 0.32 mm i.d.), with run times less than 15 min. However, the mass spectra of the nonderivatized TMAs, except 2,4,6-trimethoxyamphetmine (TMA-6), showed insufficient difference for unambiguous discrimination. On the other hand, the mass spectra of the TFA derivatives of the six isomers exhibited fragments with significant intensity differences, which allowed the unequivocal identification of all the aromatic positional isomers investigated in the present study. This GC-MS technique in combination with TFA derivatization, therefore, is a powerful method to discriminate these isomers, especially useful to distinguish the currently controlled 3,4,5-trimethoxyamphetmine (TMA-1) and 2,4,5-trimethoxyamphetmine (TMA-2) from other uncontrolled TMAs.     

Development of two fully automated quick,easy, cheap,effective, rugged,and safe pretreatment methods for the extraction of psychotropic drugs from whole blood samples

Quick, easy, cheap, effective, rugged, and safe extraction strategies are becoming increasingly adopted in various analytical fields to determine drugs in biological specimens. In the present study, we developed two fully automated quick, easy, cheap, effective, rugged, and safe extraction methods based on acetonitrile salting-out assisted liquid-liquid extraction (method 1) and acetonitrile salting-out assisted liquid-liquid extraction followed by dispersive solid-phase extraction (method 2) using a commercially available automated liquid-liquid extraction system. We applied these methods to the extraction of 14 psychotropic drugs (11 benzodiazepines and carbamazepine, quetiapine, and zolpidem) from whole blood samples. Both methods prior to liquid chromatography–tandem mass spectrometry analysis exhibited high linearity of calibration curves (correlation coefficients, > 0.9997), ppt level detection sensitivities, and satisfactory precisions (< 8.6% relative standard deviation), accuracies (within ± 16% relative error), and matrix effects (81–111%). Method 1 provided higher recovery rates (80–91%) than method 2 (72–86%), whereas method 2 provided higher detection sensitivities (limits of detection, 0.003–0.094 ng/mL) than method 1 (0.025–0.47 ng/mL) owing to the effectiveness of its dispersive solid-phase extraction cleanup step. These fully automated extraction methods realize reliable, labor-saving, user-friendly, and hygienic extraction of target analytes from whole blood samples.