Solventless Method Research Articles

Syntheses and Characterizations of Bismuth Nanofilms and Nanorhombuses by the Structure-Controlling Solventless Method

Substrate-free bismuth nanofilms with an average thickness of 0.6 nm (sigma = +/-14.1%) and monodisperse layered Bi nanorhombuses with an average edge length of 21.5 nm (sigma = +/-14.7%) and thickness of 0.9 nm (sigma = +/-25.8%) have been successively synthesized by structure-controlling solventless thermolysis from a new layered bismuth thiolate precursor with a 31.49 A spacing. The morphologies result from self-control at an atomic level by the layered Bi(SC(12)H(25))3 crystal structure. The formation of the Bi nanofilm intermediate provides significant substantiation for this synthesis method, and detailed evidence on the conversion progress has been obtained. Both the films and the rhombuses have been characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectrometry (EDX), high-resolution TEM (HRTEM), and atomic force microscopy (AFM) measurements. Special UV-vis electronic absorption spectra of the nanoproducts have been studied.

Determination of cannabinoids in biological samples using a new solid phase micro-extraction membrane and liquid chromatography–mass spectrometry

A simple, rapid and relatively solventless method for extraction of objective compounds would be useful for forensic, judicial and clinical purposes. Solid phase micro-extraction membrane (SPMEM) is one such extraction technique that integrates sampling, extraction and concentration into a single step, and combines the advantages of both the solid phase micro-extraction (SPME) and membrane separation. In this study, a new kind of membrane was prepared using polyamide and Tenax compounds, and applied to solid phase micro-extraction. Characteristics of the membrane such as adsorption capacity were tested. Extraction conditions such as adsorption time, desorption solvents, desorption time and assisted desorption treatment methods were studied and optimized. Tetrahydrocannabinol (THC) and cannabidiol (CBD) in blood and brain of the injected male mice, and in spiked human urine were extracted using this solid phase micro-extraction membrane method. The extracted THC and CBD were further determined with LC–MS using APCI. Ions analyzed in single ion monitoring mode were 315 for THC and CBD, and 318 for the deuterated THC internal standard.

New Drugs & Devices

The 6,6′-bis(3-benzonitrile-3,4-dihydro-2H-benzo[e][1,3]oxazinyl) isopropane (BA-PABN) was synthesized from bisphenol-A, p-aminobenzonitrile and paraformaldehyde via solventless method. The chemical structure of BA-PABN was confirmed by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and elemental analysis, and the polymerization of BA-PABN was investigated by FTIR, solid-state 13C NMR, and differential scanning calorimetry. BA-PABN undergoes the oxazine ring-opening polymerization and the cyclotrimerization of cyano groups with the formation of the corresponding polybenzoxazine (PBA-PABN). Dynamic mechanical analysis results show the storage modulus of PBA-PABN at 25 °C is about 2.7 GPa, and the glass transition temperature is 190 °C. The 5% and 10% weight loss temperatures of PBA-PABN are 300 and 325 °C in both air and nitrogen, respectively. The char yield is about 43% at 800 °C in nitrogen, whereas almost no degradation residue is remained at 750 °C in air.