Determination of ecgonine and seven other cocaine metabolites in human urine and whole blood by ultra-high-pressure liquid chromatography–quadrupole time-of-flight mass spectrometry

Ecgonine is suggested to be a promising marker of cocaine (COC) ingestion. A combined mass spectrometry (MS) and tandem MS (MS/MS) method was developed to simultaneously determine ecgonine and seven other metabolites of cocaine in human urine and whole blood with ultra-high-pressure liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. The compounds were extracted from as little as 100 μL of sample by solid-phase extraction with a 96-well μElution solid-phase extraction plate. The protonated molecules or fragment ions at accurate mass acquired in MS mode were used to quantify specific analytes, following by dedicated MS/MS identification. The assay was linear in the range from 5 to 50-100 ng/mL for urine samples, except for ecgonine methyl ester (10-200 ng/mL) and ecgonine (40-400 ng/mL), and was linear from 1-2 to 50 ng/mL for whole blood samples, except for ecgonine methyl ester (20-1,000 ng/mL) and ecgonine (40-2,000 ng/mL). The correlation coefficients were all greater than 0.99. The limits of detection ranged from 0.2 to 16 ng/mL, and the lower limits of quantification ranged from 1 to 40 ng/mL. The repeatability and intermediate precision were 18.1 % or less. The accuracy was in the range from 80.0 to 122.9 %, process efficiencies were in the range from 8.6 to 177.4 %, matrix effects were in the range from 28.7 to 171.0 %, and extraction recoveries were in the range from 41.0 to 114.3 %, except for ecgonine (12.8 % and 9.3 % at low and high concentrations, respectively). This method was highly sensitive in comparison with previously published methods. The validated method was successfully applied to the analysis of real samples derived from forensic cases, and the results verified that, on the basis of data from four positive samples, ecgonine is a promising marker of cocaine ingestion.

PCR-based detection of gene transfer vectors: application to gene doping surveillance

Athletes who illicitly use drugs to enhance their athletic performance are at risk of being banned from sports competitions. Consequently, some athletes may seek new doping methods that they expect to be capable of circumventing detection. With advances in gene transfer vector design and therapeutic gene transfer, and demonstrations of safety and therapeutic benefit in humans, there is an increased probability of the pursuit of gene doping by athletes. In anticipation of the potential for gene doping, assays have been established to directly detect complementary DNA of genes that are top candidates for use in doping, as well as vector control elements. The development of molecular assays that are capable of exposing gene doping in sports can serve as a deterrent and may also identify athletes who have illicitly used gene transfer for performance enhancement. PCR-based methods to detect foreign DNA with high reliability, sensitivity, and specificity include TaqMan real-time PCR, nested PCR, and internal threshold control PCR.     

A quantitative and comprehensive method to analyze human milk oligosaccharide structures in the urine and feces of infants

Human milk oligosaccharides (HMOs), though non-nutritive to the infant, shape the intestinal microbiota and protect against pathogens during early growth and development. Infant formulas with added galacto-oligosaccharides have been developed to mimic the beneficial effects of HMOs. Premature infants have an immature immune system and a leaky gut and are thus highly susceptible to opportunistic infections. A method employing nanoflow liquid chromatography time-of-flight mass spectrometry (MS) is presented to simultaneously identify and quantify HMOs in the feces and urine of infants, of which 75 HMOs have previously been fully structurally elucidated. Matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance MS was employed for high-resolution and rapid compositional profiling. To demonstrate this novel method, samples from mother–infant dyads as well as samples from infants receiving infant formula fortified with dietary galacto-oligosaccharides or probiotic bifidobacteria were analyzed. Ingested oligosaccharides are demonstrated in high abundance in the infant feces and urine. While the method was developed to examine specimens from preterm infants, it is of general utility and can be used to monitor oligosaccharide consumption and utilization in term infants, children, and adults. This method may therefore provide diagnostic and therapeutic opportunities.

Fingerprints of Phalaenopsis Tissues in Growth and Spike Induction Periods—A Solid‐state 13C NMR Approach

Solid‐state Nuclear Magnetic Resonance (ss‐NMR) ¹³C single‐pulse excitation spectroscopy in combination with the magic‐angle spinning (MAS) technique was applied to a series of Phalaenopsis tissues, including the leaf, sheath, stem, and root, at different growth and spiking periods. Compared with{¹H}/¹³C cross‐polarization MAS spectra, the ¹³C single‐pulse excitation MAS spectra displayed very distinct spectral patterns, recognizable as fingerprints of the tissues studied. ¹Here, we demonstrate that solid‐state ¹³C single‐pulse excitation NMR spectroscopy provides a direct and robust analytical tool for studying the various tissues of Phalaenopsis in different growth and spiking induction periods.     

Improved staining of phosphoproteins with high sensitivity in polyacrylamide gels using Stains‐All

An improved Stains‐All (ISA) staining method for phosphoproteins in SDS‐PAGE was described. Down to 0.5–1 ng phosphoproteins (α‐casein, β‐casein, or phosvitin) can be successfully selectively detected by ISA stain, which is approximately 120‐fold higher than that of original Stains‐All stain, but is similar to that of commonly used Pro‐Q Diamond stain. Furthermore, unlike the original Stains‐All protocol that was time consuming and light unstable, ISA stain could be completed within 60 min without resorting to protect the gels from light during the whole staining procedure. According to the results, it is concluded that ISA stain is a rapid, sensitive, specific, and economic staining method for a broad application to the research of phosphoproteins.     

The study of the stability of aqueous three-phase fire-resistant foam in typical liquidus hydrocarbons

The utilization of solid particles in aqueous foam has a great potential in improving fire fighting efficiency. In this study, aqueous foam supported by micro fly-ash (FA) was prepared and its stability in a specific type of oil was characterized. Firstly, different amount of FA was added to study the influence of FA concentration on foamability. It showed that within a specific extent, foam expansion ratio increased with the increasing of FA concentration. And compared with conventional foams, oil resistance of FA stabilized foams, which was investigated by analyzing drainage rate and evolution process with a self-made apparatus, was remarkably improved when FA concentration exceed 4.8wt.%. Secondly, SiO₂ and Al₂O₃ particles with different median sizes were used to study the effect of particle size on stability. However, the smaller hydrophilic particles didn’t behave better as expected. Moreover, the foam stability in three hydrocarbons was evaluated in the same way. The results indicated that the short chain hydrocarbons had much stronger detrimental effect to both two-phase foam and three-phase foam. But overall, the three-phase foam stabilized by FA exhibited much better oil resistance, so it can be used as a promising material for pool fire extinguishing and prevention.GRAPHICAL ABSTRACT     

Synthesis and characterisation of 3-armed dendritic molecules with triphenylbenzene or triphenyltriazine as core and triphenylene derivative as shells

Two series 3-armed dendritic molecules with their 1,3,5-tris(4-methyloxyphenyl) benzene or 2,4,6-tris(4- hydroxylphenyl)-1,3,5-s-triazine core and triphenylene derivative shells connected by soft hydrocarbon chains have been synthesised and fully characterised. Whether liquid crystal (LC) or photoluminescence materials have been tuned by changing the length of the soft chain and they have been studied by POM, DSC, XRD, UV-Vis and PL. The results show that all the new dendritic compounds display UV to blue fluorescence in solvents such as DCM, THF and acetone. The TC3 compound bearing 1,3,5-tris(4-hydroxylphenyl) benzene core exhibits LC property with rectangular columnar phase (Col_r) on cooling.     

Crystallization of calcium carbonate controlled by Pluronic P123 in room-temperature ionic liquid

The crystallization of calcium carbonate (CaCO₃) controlled by Pluronic P123 in a room-temperature ionic liquid, ethylamine nitrate (EAN), was investigated. The CaCO₃ aggregates were obtained by rapid mixing of ammonium carbonate ((NH₄)₂CO₃) and calcium chloride (CaCl₂). Cubic calcite, spherical vaterite, and bagel-like vaterite were obtained easily by changing P123 concentration and reaction temperature. The morphologies of the as-prepared CaCO₃ aggregates were investigated by transmission electron microscopy and scanning electronic microscopy. The phase change of the obtained crystals was confirmed by X-ray diffraction and Fourier transform infrared spectroscopy. It was shown that higher P123 concentration and higher reaction temperature favor the formation of vaterite in EAN. Unusual bagel-like vaterite was first obtained at 60 °C in the presence of 5 g/L P123 in EAN. Mineralization of CaCO₃ regulated by P123 in EAN is a simple, novel, and environment-friendly strategy for vaterite synthesis.     

A p‐Quinodimethane‐Bridged Porphyrin Dimer

A p‐quinodimethane (p‐QDM)‐bridged porphyrin dimer 1 has been prepared for the first time. An unexpected Michael addition reaction took place when we attempted to synthesize compound 1 by reaction of the cross‐conjugated keto‐linked porphyrin dimers 8 a and 8 b with alkynyl/aryl Grignard reagents. Alternatively, compound 1 could be successfully prepared by intramolecular Friedel–Crafts alkylation of the diol‐linked porphyrin dimer 14 with concomitant oxidation in air. Compound 1 shows intense one‐photon absorption (OPA, λ_max=955 nm, ε=45400 M ^?1 cm^?1) and a large two‐photon absorption (TPA) cross‐section (σ⁽²⁾_max=2080 GM at 1800 nm) in the near‐infrared (NIR) region due to its extended π‐conjugation and quinoidal character. It also exhibits a short singlet excited‐state lifetime of 25 ps. The cyclic voltammogram of 1 displays multiple redox waves with a small electrochemical energy gap of 0.86 eV. The ground‐state geometry, electronic structure, and optical properties of 1 have been further studied by density functional theory (DFT) calculations and compared with those of the keto‐linked dimer 8 b . This research has revealed that incorporation of a p‐QDM unit into the porphyrin framework had a significant impact on its optical and electronic properties, leading to a novel NIR OPA and TPA chromophore.     

Microstructure, distribution and properties of conductive polypyrrole/cellulose fiber composites

Highly intrinsic conductive polypyrrole/cellulose fiber composites (CF) were successfully prepared through in situ chemical oxidation polymerization simply by increasing fiber concentration at the same dosage of pyrrole, oxidant and dopant (based on the weight of dry fiber). FeCl₃ and anthraquinone-2-sulfonic acid sodium salt (AQSNa) were utilized as oxidant and dopant. As fiber concentration increased from 1 % (CF1) to 20 % (CF20), N and S content increased from 0.24 and 0.25 % to 1.24 and 0.89 %, and great increase in the retention of PPy and AQSNa was confirmed by elemental analysis. In addition, on the surface of conductive fiber, PPy of compact fibroid structure was detected instead of interconnected globular structure at higher fiber concentration. Furthermore, scanning transmission electron microscope and X-ray photoelectron spectroscopy (XPS)-depth profile analysis demonstrated denser and more uniformly distributed PPy inside fiber wall for CF20, while PPy tended to deposit on the surface of fiber for CF1. Fourier transform infrared spectroscopy, together with XPS certified that the PPy with longer conjugation length and higher doping level across the conductive fiber was obtained at higher fiber concentration. The doping level for CF10 decreased from 21.55 to 16.39 % with increasing fiber wall thickness, while that of CF20 decreased slightly from 30.73 to 24.10 %. The resulting CF20 showed lowest surface resistivity of 0.433 KΩ/square, as well as improved electro-conductivity stability. The incorporation of more PPy in CF improved the thermal stability.