Qualitative gas chromatographic analysis of bacterial amines as their Schiff bases and other derivatives

Summary Columns of SE-30 and OV-17 on Chromosorb W, Apiezon N on Chromosorb G and Tenax-GC porous polymer were compared for their ability to separate bacterial amines converted to carbethoxy, dinitrophenyl, trimethylsilyl, Schiff base and fluorinated Schiff base derivatives.Tenax-GC performed less well than the other packings with respect to the number of plates and peak resolution. Dinitrophenyl and trimethylsilyl derivatives were both unsatisfactory for analysis of bacterial amines. Schiff bases and their fluorinated derivatives were found to be the most suitable. However, the former were preferred as the use of fluorinated Schiff bases confered little advantage when a flame ionization detector was employed. A maximum of 16 amines was separated, using columns of OV17 on Chromosorb W programmed from 110 °C to 280 °C at 5.5 °C min^–1 after an initial holding time of 6 min. The application of the method to analysis of cultures ofProteus mirabilis yielded two amines tentatively identified asiso-butylamine andiso-amylamine.     

GAS-LIQUID CHROMATOGRAPHY OF PROPANOL,PROPYLAMINE, AND DIPROPYLAMINE

Abstract

A gas-liquid chromatographic system was developed for separation and measurement of residue quantities of propanethiol, propylamine, dipropylamine, and propanol. The 9% Amine 220 on Chromosorb W column with flame ionization detection was utilized for levels of 200 nanograms.     

Measurement of adenine nucleotide levels with an adenine analyser as an index of freshness of porgy

In a prototype of an adenine analyser, adenosine and adenine nucleotides were derivatized with a fluorescent reagent, bromoacetaldehyde, after separation on a Hitachi gel No. 3012-N column by high-performance liquid chromatography. The previous analyser was improved by using a shorter reaction coil and by introduction of a Hitachi gel No. 3013-N with 5-microns particles of porous polystyrene-divinylbenzene, and applied to estimate the freshness of porgy. Total amounts of ATP, ADP and AMP in an isolated muscle just after death gradually decreased to 60% of the original amount after 5 h, and the ATP content rapidly decreased to 20% after 1 h. A good correlation was found between the levels of total adenine compounds and the energy charge values obtained from nineteen porgies frozen at a prerigour state. On the other hand, there existed no relationship between total adenine levels and the K values, which were indices for estimating freshness of fish. The analyser will be useful to evaluate the freshness of tissues and cells based on the higher contents of total adenine compounds, especially ATP.     

Determination of Captan,Folpet, and Captafol in Water,Apples, and Lettuce By Quantitative Thin-Layer Chromatography

Abstract

Captan, folpet, and captafol were determined in water, lettuce, and apples by TLC of extracts on preadsorbent silica gel layers, detection with silver nitrate reagent, and densitometric scanning. The fungicides were extracted from water on Chromosorb 102 raicrocolumns. Cleanup on a Florisil column was required for the food extracts. Recoveries from distilled and tap water ranged from 76–98% at 0.02 ppm and 81–94% at 0.007 ppm. Recoveries from lettuce ranged from 88–94% and from apples 84–90%, both at 0.25 ppm. The selectivity, sensitivity, and precision of the method are adequate for routine residue analysis.     

The Analysis of Air for Acetone Cyanohydrin Using Solid Sorbent Sampling and Gas Chromatography

Abstract

A method for sampling and analysis of airborne acetone cyanohydrin is described. The analyte is collected on Porapak QS, a silylated styrene-divinylbenzene porous polymer. Samples are desorbed with ethyl acetate and analyzed by gas chromatography using a nitrogen-specific detector and a teflon column packed with 5% OV-17 on Chromosorb T. The detection limit is estimated to be 0.1 μg/mL acetone cyanohydrin in ethyl acetate. The method was tested by evaporating from 1.0 to 50 μg of the analyte onto sorbent beds of Porapak QS and exposing the samples to a humidified airstream for 15 min. Quantitative recovery was obtained for samples stored for one day at ambient temperature or for seven days if the samples were refrigerated immediately after collection.     

Gas Chromatographic Analysis of DDT-Type Compounds

Abstract

Four columns have been used experimentally in combination with an electron capture detector, which allowed the determination of 25 DDT-type compounds, some of which have been reported as DDT breakdown products in many biological and nonbiological systems. The liquid phases were 5% QF-i, 5% Igepal, 5% Versamid 900, and 5% DC-11. The solid support for the 4 columns was 80 to 100 mesh Chromosorb W. Optimal temperatures (°C) for the columns were 190 (column), 210 (detector), and 230 (injector port). Optimal nitrogen flow rate was 35 ml/min., for all columns. The trimethylsilyl derivatives of the polar DDT-type compounds, DBH, DDOH, Dicofol, and DDA were successfully gas chromatographed on the column 5% QF-1 and the mixed column 2.5% QF-1 + 2.5% SE-30.     

Lead Aerosol Collection Studies Using Solid Sorbent Packed Sampling Tubes

Abstract

The use of packed-bed solid sorbent tubes was investigated for the collection and concentration of lead and lead compound aerosols utilizing a lead metal laboratory test atmosphere and lead containing automobile exhaust. Four different sorbents were tested: alumina (100–150 mesh), silica gel (80–200 mesh), Chromosorb 102 (60–80 mesh), and Tenax-GC (80–100 mesh). The following average collection efficiencies were observed for the first portion of each sorbent in the tube (200 mg of sorbent) when sampling automobile exhaust: 95.8 ± 5.7 % for alumina, 98.5 ± 3.2 % for silica gel, 98.0 ± 3.7 % for Chromosorb 102, and 99.2 ± 2.6 % for Tenax-GC. Using the lead metal test aerosol, the average efficiencies were 99.2 ± 1.0, 99.2 ± 1.1, 99.9 ± 0.1, and 100.0 ± 0.0 % for the alumina, silica gel, Chromosorb 102, and Tenax-GC, respectively. Consideration of percent collection efficiency, blank values, and elution efficiency of lead from the sorbent indicated that Tenax-GC provided the best results.     

Determination of Octadecylamine in Water by Quantitative High Performance thin Layer Chromatography

Abstract

Octadecylamine (ODA) was isolated from water by solvent extraction with ethylene dichloride or trapping on a micro Chromosorb column. The ODA in the extract or column eluent was chromatographed on a high performance silica gel layer, detected by spraying with ninhydrin, and quantified by reflectance densitometry. Recovery at 3 ppm averaged 81.3% using extraction and 94.0% with the column. Recovery at 0.3 ppm was 94.2% using the column procedure.     

Rapid gas chromatography of isomeric aromatic hydrocarbons

Summary A method is described for the gas-chromatographic separation of isomeric aromatic hydrocarbons up to C₉ using modified Bentone 34 short-capillary or high-efficiency small-bore packed columns. Properties of both column types are discussed. A mixture of ethylbenzene and isomeric xylenes can be separated within less than 3 min and the separation of a mixture of ethylbenzene, isomeric xylenes, ethyltoluenes, trimethylbenzenes and n-hydrocarbons C₆ to C₉ can be achieved within less than 5 min on a column 3 m×0.8 mm i. d. packed with Bentone 34 + dinonylphthalate on Chromosorb W.

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Zusammenfassung Es wird eine Methode zur schnellen gas-chromatographischen Trennung isomerer aromatischer Kohlenwasserstoffe bis C₉ mit modifiziertem Bentone 34 an kurzen Capillarsäulen oder an gepackten Hochleistungs-Trennsäulen mit kleinem Innendurchmesser beschrieben. Die Eigenschaften der beiden Säulentypen werden diskutiert. Ein Gemisch von Äthylbenzol und Xylolisomeren kann in weniger als 3 min getrennt werden. Eine Trennung von Äthylbenzol, isomeren Xylolen, Äthyltoluolen, Trimethylbenzolen und Kohlenwasserstoffen C₆ bis C₉ kann innerhalb von 5 min an einer Säule von 3 m×0,8 mm i.D., gepackt mit Bentone 34 und Dinonylphthalat auf Chromosorb W, erreicht werden.

     

Quantification of monosaccharides through multiple‐reaction monitoring liquid chromatography/mass spectrometry using an aminopropyl column

A simple, sensitive, and reproducible quantitative liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was designed for the simultaneous quantification of monosaccharides derived from glycoprotein and blood serum using a multiple‐reaction monitoring (MRM) approach. Sialic acids and neutral monosaccharides were efficiently separated using an amino‐bonded silica phase column. Neutral monosaccharide molecules were detected as their aldol acetate anion adducts [M + CH₃CO₂]^? using electrospray ionization in negative ion MRM mode, while sialic acids were detected as deprotonated ions [M–H]^?. The new method did not require a reduction step, and exhibited very high sensitivity to carbohydrates with limits of detection of 1 pg for the sugars studied. The linearity of the described approach spanned over three orders of magnitude (pg to ng). The method was validated for monosaccharides originating from N‐linked glycans attached to glycoproteins and glycoproteins found in human blood serum. The method effectively quantified monosaccharides originating from as little as 1 µg of glycoprotein and 5 µL of blood serum. The method was robust, reproducible, and highly sensitive. It did not require reduction, derivatization or postcolumn addition of reagents. Copyright © 2010 John Wiley & Sons, Ltd.     

Simultaneous spectrophotometric and liquid chromatographic determination of dextromethorphan hydrobromide,phenylephrine hydrochloride,and carbinoxamine maleate in pharmaceutical preparations

Simultaneous determination of dextromethorphan hydrobromide (DEX), phenylephrine hydrochloride (PHEN), and carbinoxamine maleate (CAR) in pharmaceutical preparations was performed by using liquid chromatograpy (LC) and spectrophotometry. In LC, the separation was achieved on a C18 column and the optimal mobile phase for satisfactory separation in a gradient elution program was found to be acetonitrile-sodium perchlorate solution (5: 95, v/v) initially, then a linear gradient up to 60% acetonitrile in 8 min. In spectrophotometric method, a chemometric technique, principal component regression (PCR), was used. In the method, the absorbance data matrix corresponding to the concentration data matrix was obtained by the measurement of absorbances in their zero order spectra by Δλ = 1 nm in the 210–300 nm range. Then, the calibration was obtained by using this data matrix for the prediction of unknown concentrations of DEX, PHEN, and CAR in their ternary mixture. The methods proposed were validated and successfully applied to a pharmaceutical preparation, capsule, and the results were compared.     

高效阴离子交换-脉冲安培检测同时分析单糖和糖醛酸

建立了高效阴离子交换-脉冲安培检测(HPAE-PAD)同时分离测定8种单糖和2种糖醛酸的分析方法。以CarboPacPA20阴离子交换柱为分离柱,以2mmol/LNaOH溶液将8种单糖从分离柱上洗脱,而后用NaAc(50~200mmol/L)梯度淋洗2种糖醛酸,淋洗液流速为0.5mL/min,总分析时间为30min。在优化的分离测定条件下,8种单糖和2种糖醛酸的检出限为2.5~14.4μg/L(进样体积25μL,峰面积定量)。5mg/L的10种化合物的混合标准溶液连续7次进样,峰面积的相对标准偏差为0.3%~1.5%。用所建立的方法测定了多糖水解液和木材半纤维素水解液中的单糖和糖醛酸含量。     

The influence of flexible spacer and the chirality of the core on the formation of chiral nematic phase of symmetric dimers containing trifluoromethyl terminal

Seven symmetric liquid crystal (LC) dimers containing different chiral cores and LC arms have been synthesised, termed EPDA-(R,S)PD, TFBDA-(R,S)PD, TFBA-(R,S)PD, TFBDA-(R)PD, TFBA-(R)PD, TFBDA-IB and TFBA-IB, respectively. TFBDA-(R,S)PD, TFBA-(R,S)PD, TFBDA-(R)PD and TFBDA-IB displayed chiral smectic A (SmA*) phase, while EPDA-(R,S)PD, TFBA-(R)PD and TFBA-IB exhibited chiral nematic (N*) phase. The effects of flexible spacer, structural type of LC arms and the chirality of the cores on the thermal properties of the dimers and the formation of N* phase have been studied. The results indicated that the chiral core was prone to induce the N* phase in LC dimer that contained nematic arms although the chirality of the core is very weak, while for the smectic LC arms containing CF3 terminal, the removal of the flexible spacer between chiral core and rigid LC units was conducive to the formation of N* phase. For example, TFBDA-(R)PD and TFBDA-IB displayed SmA* phase, while TFBA-(R)PD and TFBA-IB exhibited N* phase. However TFBA-(R,S)PD did not display N* phase, which reminded us that the chirality of the core and the conformation of the dimer also played an influence in the formation of the LC phase.     

Liquid Chromatographic Determination of Cyclosporine-A in Blood,with Chromosorb P Columns Used for Sample Purification

Abstract

A fast liquid-chromatographic determination of whole-blood cyclosporine A concenration is described. A sample preparation consisting of diethyl ether extraction and Chromosorb P column purification of extract, requires 1 mL of whole blood and takes 10 min of technical effort per sample. A reversed-phase C₁ column (5-μm particles) is used, with acetonitrile/methanol/water (20/45/35 by vol) as mobile phase. Cyclosporine A is quantified by absorbance at 214 nm, with cyclosporine D as internal standard. Chromatographic development is complete in 8 min. Linearity is verified by a five-point calibration curve in the range 50–900 μg/L, correlation coefficient r>0.998, y = 0.001x ? 0.053. Lower limit of sensitivity is 25 μg/L. Extraction efficiency was over 70%, accuracy varied between ?7.1% and +3.3%s, CVs were <5.8% within run, <7.5% between runs. No interference was observed from both endogenous compounds, and 33 drugs eventually co-administered during immunosuppression. Over 1,000 patient samples have been analysed by this method in our laboratory in about one year, without any sign of column deterioration.     

基于双“click”反应的树枝状化合物的一锅法合成

将叠氮和炔基之间Cu(I)催化的“click”反应以及蒽和马来酰亚胺之间的Diels-Alder反应相结合, 采用“一锅法”技术合成出结构完美且外围含有亲水性寡聚乙二醇(OEG)链段的树枝状化合物4, 产率为75%. 利用核磁共振氢谱、碳谱、紫外、荧光光谱以及MALDI-TOF质谱等对产物进行了表征与分析, 并利用凝胶渗透色谱(GPC)对其纯度进行了测试.     

Heteroaromatization with Sulfonamido Phenyl Ethanone,Part I: Synthesis of Novel Pyrrolo[2,3-D]Pyrimidine and Pyrrolo[3,2-E][1,2,4]Triazolo[1,5-C]Pyrimidine Derivatives Containing Dimethylsulfonamide Moiety

4-(5-Amino-4-cyano-1-p-tolyl-1H-pyrrol-3-yl)-N,N-dimethyl-benzenesulfonamide (4) was prepared and converted to several pyrrolo[2,3-d]pyrimidin-5-yl)-N,N-dimethyl-benzenesulfonamide derivatives (5,7,9, and 13). Cyclocondensation of 13 with different electrophilic carbon reagents afforded several 4-(N,N-dimethylaminosulfonylphenyl)]pyrrolo[3,2-e][1,2,4]triazolo[1,5-c]-pyrimidine derivatives (14–17,19, and 20); IR, ¹HNMR, and mass spectra of the newly synthesized compounds were recorded. Most of the obtained compounds were screened against Gram-positive and Gram-negative bacteria and fungi, for which some of these derivatives gave promising results.     

A Comparison of Polymer Separation Efficiency and Resolution by Gradient LC,GPC and TLC

Abstract

The specific resolution of gradient LC and reversed phase TLC methods for the separation of different molecular weight standards of poly(isoprene), poly(ethylene glycol), poly(ethylene oxide), poly(styrene) and poly(α-methylstyrene) were determined. It was found that gradient LC has an order of magnitude greater resolving power (for high polymers) than gel permeation chromatography (GPC) while TLC had from two to five times the resolving power of GPC in the molecular weight range investigated. This is a direct result of the greater selectivity of gradient LC and TLC techniques. The specific resolution is also dependent on the type of gradient used to achieve fractionation for the LC technique.     

Design,synthesis, molecular docking,and biological studies of novel phytoestrogen-tanaproget hybrids

A diverse range of novel and highly functionalized flavonoid-based tanaproget hybrids were synthesized and evaluated in vitro for their antimicrobial and antiproliferative activities. Novel products were synthesized in good yields (81–95%) under Pd-catalyzed reaction from bromo flavones and tanaproget boronic acids within 18–20 min at 60 °C. Bioassay results exhibited excellent activities against both hormone-dependent and hormone-independent human breast cancer cells (MCF-7, MDA-MB-231, DU-145, PC-3, and HeLa). Among them, compounds 4e, 9a, 9c, 9e, 9 g, 9 h, 9 m, and 9n displayed excellent activity. Compounds 4d, 4o, and 9o were found equally potent against C. albicans compared to fluconazole. Compound 5c showed better antibacterial activity against S. aureus. Compounds 5a, 9i, 9o, and 10c have shown admirable antibacterial activity against E. coli.     

Gas—liquid chromatography on phenyl-substituted polysiloxane stationary phases,alcohols and alcohol benzoyl derivatives

Retention indices of 54 alcohols and 55 alcohol benzoyl derivatives measured on short stainless steel columns (1 m × 2 mm i.d.) filled with Chromosorb G (AWDMCS (HP)) coated with 5% ($\text{w}\text{w}$) SE-30, OV-3, OV-7, OV-11, OV-17 or OV-25 stationary phases at 100°C, 120°C and 140°C, appear to be very accurate, provided that there is careful control of the Chromatographic process. Values of the temperature dependence of retention index of alcohols and benzoates, and variations of these values with the polarity of the phase used, are given.     

Calculation of the heat of copper cluster formation in MgO lattice by the interacting bonds method

The heat of formation of some copper clusters in a MgO lattice has been calculated by the interacting bonds method.

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MgO.