Bridged Hybrid Research Articles

Construction and Chromatographic Performance of a Novel Triazole Bridged Hybrid Bilayer Cyclodextrin Chiral Stationary Phase

Construction and Chromatographic Performance of a Novel Triazole Bridged Hybrid Bilayer Cyclodextrin Chiral Stationary Phase

Multicomponent LC–MS/MS screening method for detection of new psychoactive drugs, legal highs, in urine—Experience from the Swedish population

The advent of new not yet legally regulated psychoactive substances sold over the Internet has created a challenge for clinical toxicology and drug testing laboratories. The routine use of immunoassay screening may no longer be the optimal solution in many instances since the number of analytes covered is becoming insufficient. The aim of this work was to design, validate and apply a multi-component LC-MS/MS method suitable for screening of a large number of target analytes belonging to the class of new psychoactive substances - legal highs. The analytical method was using a five-fold dilution of urine with internal standard (pethidine-d5) and injection of 2μL. The chromatographic system was using a 1.7-μm 100mm×2.1mm Ethylene Bridged Hybrid (BEH) C18 column and gradient elution with a flow rate of 600μL/min. Solvent A consisted of 0.1% formic acid and Solvent B was 100% acetonitrile. The gradient elution application was designed to have a wide polarity coverage with total run time of 4.0min. The tandem mass spectrometer was using an electrospray interface and operated in positive mode. Selected reaction monitoring of two ion transitions was used for each of 26 analytes. Method validation demonstrated limited influence from urine matrix, linear response within the measuring range (0.1-10μg/mL), acceptable imprecision in quantification (CV<15%). Some analytes were found not to be stable in urine upon storage. The method was successfully applied in routine drug testing. A total of 87 positive samples with 100 analytical findings were found to contain O-desmethyl-cis-tramadol (mostly without mitragynine), methylenedioxypyrovalerone, 4-fluoroamphetamine, methoxetamine, desoxypipradol, 4-fluoromethcathinone, 5,6-methylenedioxy-2-aminoindane, 4-methylmethcathinone, 3-fluoromethcathinone, 4-hydroxy-N-methyl-N-ethyltryptamine, α-methylamino-butyrophenone and 4-methoxymethcathinone.

Separation and Identification of Individual Alginate Oligosaccharides in the Feces of Alginate-Fed Pigs

This research aimed to develop a method for analyzing specific alginate oligosaccharides (AOS) in a complex matrix such as pig feces. The data obtained were used to study alginate degradation by the microbiota in the large intestine during adaptation, including the individual variation between pigs. A method using an UHPLC system with an ethylene bridged hybrid (BEH) amide column coupled with MS(n) detection was able to distinguish saturated and unsaturated AOS with DP 2-10. Isomers of unsaturated trimer and tetramer could be separated and annotated. In the feces, saturated and unsaturated AOS were present. The presence of unsaturated AOS indicates that the microbiota produced alginate lyase. The microbiota utilized unsaturated AOS more than saturated AOS. The results also suggested that guluronic acid at the reducing end of AOS inhibits the utilization by microbiota during the first weeks of adaptation. After adaptation, the microbiota was able to utilize a broader range of AOS.

ChemInform Abstract: Analytical Tools for the Analysis of Carotenoids in Diverse Materials

AbstractReview: 99 refs.

Quantitative Method Validation for the Analysis of 27 Antidepressants and Metabolites in Plasma With Ultraperformance Liquid Chromatography–Tandem Mass Spectrometry

A fast and selective ultraperformance liquid chromatographic-tandem mass spectrometric method was developed and validated for the simultaneous quantification of amitriptyline, citalopram, clomipramine, desipramine, desmethylcitalopram, desmethylclomipramine, desmethyldosulepin, desmethyldoxepin, desmethylfluoxetine, desmethylvenlafaxine, didesmethylcitalopram, dosulepin, doxepin, duloxetine, fluoxetine, fluvoxamine, imipramine, maprotiline, mianserin, mirtazapine, moclobemide, nortriptyline, paroxetine, reboxetine, sertraline, trazodone, and venlafaxine in 100 μL of plasma. After liquid-liquid extraction with 1-chlorobutane, analytes were separated on a BEH (Ethylene Bridged Hybrid) C18 analytical column with gradient elution. The compounds were ionized and detected over 7-minute analysis time by electrospray ionization tandem mass spectrometry with multiple reaction monitoring. Limits of quantification and limits of detection ranged from 2.5 to 10 ng/mL and 0.2 to 10 ng/mL, respectively. Intra- and interassay imprecision were lower than 15% for all the compounds except for mirtazapine, moclobemide, and desmethylclomipramine [relative standard deviation (RSD) < 20%], and the bias of the assay was lower than 15% for all the compounds except for fluvoxamine (bias < 20.5%), evaluated with 5 commercial quality control and 3 "in-house" quality control. The extraction was found to be reproducible (RSD < 16%) (except for duloxetine RSD 21.9%) and with recoveries varying from 59% to 86%. Furthermore, the stability studies demonstrated that the processed samples were stable in the autosampler for 24 hours for all the compounds. The method was successfully applied to the analysis of authentic samples from forensic toxicology cases and external quality control assays from the Society of Toxicology and Forensic Chemistry (GTFCh). The method was completely validated and can be of interest to clinical and forensic laboratories.

Simultaneous determination of hydrolysable tannins in the petals of Rosa rugosa and allied plants

The petals of Rosa rugosa and allied plants for medicinal use contain abundant hydrolysable tannins, and they show remarkable biological activities. The activities are dependent on the structures of the hydrolysable tannins, so their contents and compositions are essential for evaluation of medicinal potency. Therefore, we optimized the simultaneous quantitative determination of the hydrolysable tannins using ultra-performance liquid chromatography. A column of ethylene bridged hybrid (BEH) phenyl (C(6) alkyl phenyl group as solid-phase modification) was shown to be most effective for the separation of hydrolysable tannins isolated from R. rugosa and related compounds when the column temperature was kept under 25 degrees C. The efficacy of the BEH phenyl column might be due to the interaction between solid phase and phenolic ester groups of hydrolysable tannins such as galloyl, hexahydroxydiphenoyl and valoneoyl groups. The relation between the retention times on the BEH phenyl column and the column temperature was demonstrated to depend on the structural characteristics of hydrolysable tannins.

Hydrodynamic chromatography for the size classification of micron and sub-micron sized packing materials

Hydrodynamic chromatography (HDC) was used as a size classification and purification method for porous bridged ethyl hybrid (BEH) packing materials (particles) in the micron to sub-micron range. Using packed column HDC, a batch of particles with size 0.76 ± 0.26 μm was fractionated to yield classified material of 1.05 ± 0.16 μm, reducing the relative standard deviation from 33% to 15%. Subsequent chromatographic evaluation of this packing material showed significant improvement in column performance and decrease in flow resistance over the unclassified material. Comparing a column packed with the classified versus non-classified material, the effective flow resistance of the two columns was decreased by 58% and the minimum HETP for the packing material was improved from 4 to 2.5 μm.

The application of novel 1.7 μm ethylene bridged hybrid particles for hydrophilic interaction chromatography

An un-derivatized 1.7 microm ethylene bridged hybrid (BEH) particle was evaluated for its utility in retaining polar species in hydrophilic interaction chromatography (HILIC), and was compared to a 3 microm un-derivatized silica material. Retentivity as a function of mobile phase pH, polar modifier and ACN content was examined. Also, the efficiency of the two particle substrates was compared by plotting HETP vs. linear velocity. Improved chemical resistance of the un-derivatized BEH particle was compared to un-derivatized silica at pH 5, demonstrating no performance deterioration over the course of 2000 injections for the BEH particle, while the silica particle deteriorated rapidly after 800 injections. Lastly, ESI-MS sensitivity as a function of particle size and separation mode was demonstrated. A 2.2 to 4.7-times higher ESI-MS response was observed on the 1.7 microm particle compared to the 3 microm particle, whereas a 5.6 to 8.8-times higher ESI-MS response was observed using HILIC as when compared to traditional RP chromatography.

Improved Structural Order, Stability, and Anion-Exchange Capacity of Cation-Mediated Bridged Hybrid Mesoscopic Materials by Using Chelating Ligands

The anion-exchange property of upgraded metal cation-mediated bridged hybrid mesoscopic material (MBH-S) is greatly improved by replacing initial unidentate ligands with chelating ligands in the framework. Compared to conventional MBH samples, the upgraded MBH-S shows a well-ordered hexagonal mesostructure and a remarkably high anion-exchange capacity. Significantly, the upgraded MBH-S shows a good hydrothermal stability and can keep its anion-exchange capacity unchanged during repeated ion-exchange procedures, which is very important for this type of material to be used in practical application as an anion exchanger. As examples, an anion molecule of tris(8-hydroxyquinoline-5-sulfonate)aluminum (Al(SQ)3) with strong luminescence can be exchanged into MBH-S, forming composite solid of MBH-S-Al(SQ)3 with very strong green luminescence under the excitation of UV light (λexc = 360 nm). A functional molecule of copper phthalocyanine tetrasulfonic acid (CuPcTS) has been employed as a guest to assemble hybrid solid material, MBH-S-CuPcTS.