Liquid chromatography-tandem mass spectrometry method for the analysis of N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine, a biocidal disinfectant, in dairy products.

A novel and reliable method to quantify residual levels of N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine in dairy products using ion-pairing reversed-phase liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and fully validated. Sample extraction was done with salting-out technique using acetonitrile and sodium chloride. For LC-MS/MS, the analyte was detected using positive electrospray ionization (ESI+) and two multiple reaction monitoring (MRM) transitions were monitored. The method was validated in the 5-150 µg kg-1 range using total error approach. Thus, performance criteria of the method were evaluated. Relative standard deviations for trueness and precision were lower than 10%; with the exception of hard pressed cheese at 5 µg kg-1 for precision. The limit of quantification (LOQ) was around 5-7 µg kg-1 depending on the matrix of interest. The method was successfully applied to accurately quantify N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine in 146 various dairy products with a maximum contamination level of 225 µg kg-1 in cheese.

Cellulose tris-(3,5-dimethylphenylcarbamate)-based chiral stationary phase for the enantioseparation of drugs in supercritical fluid chromatography: comparison with HPLC.

A cellulose tris-(3,5-dimethylphenylcarbamate)-based chiral stationary phase was studied as a tool for the enantioselective separation of 21 selected analytes with different pharmaceutical and physicochemical properties. The enantioseparations were performed using supercritical fluid chromatography. The effect of the mobile phase composition was studied. Four different additives (diethylamine, triethylamine, isopropylamine, and trifluoroacetic acid) and isopropylamine combined with trifluoroacetic acid were tested and their influence on enantioseparation was compared. The influence of two different mobile phase co-solvents (methanol and propan-2-ol) combined with all the additives was also evaluated. The best mobile phase compositions for the separation of the majority of enantiomers were CO2 /methanol/isopropylamine 80:20:0.1 v/v/v or CO2 /propan-2-ol/isopropylamine/trifluoroacetic acid 80:20:0.05:0.05 v/v/v/v. The best results were obtained from the group of basic ß-blockers. A high-performance liquid chromatography separation system composed of the same stationary phase and mobile phase of similar properties prepared as a mixture of hexane/propan-2-ol/additive 80:20:0.1 v/v/v was considered for comparison. Supercritical fluid chromatography was found to yield better results, i.e. better enantioresolution for shorter analysis times than high-performance liquid chromatography. However, examples of enantiomers better resolved under the optimized conditions in high-performance liquid chromatography were also found.

Separation of structurally related primary aliphatic amines using hydrophilic interaction chromatography with fluorescence detection after postcolumn derivatization with o-phthaldialdehyde/mercaptoethanol.

The retention behavior of primary aliphatic amines (homologous series of aliphatic alkyl amines and cycloalkyl amines) and positional isomers of alkylamines in the hydrophilic interaction chromatography mode was studied. The study was carried out on a TSKgel Amide-80 column followed by postcolumn derivatization with fluorescence detection to describe the retention mechanism of tested compounds. The effect of chromatographic conditions including column temperature, acetonitrile content in the mobile phase, mobile phase pH (ranging from 3.5 to 6.8), and salt concentration in the mobile phase was investigated. The final mobile phase consisted of acetonitrile and solution of 20 mM potassium formate pH 3.5 in ratio 80:20 v/v. The analyses were carried out at mobile phase flow rate of 1.0 mL/min and the column temperature of 20°C. The developed method was fully validated in terms of linearity, sensitivity (limit of detection and limit of quantification), accuracy, and precision according to International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use guidelines. The proposed new methods were proved to be highly sensitive, simple, and rapid, and were successfully applied to the determinations of isopropylamine, cyclohexylamine, and cyclopropylamine in relevant active pharmaceutical ingredients.

Stimulation of human osteoblast cells (MG63) proliferation using decanoic acid and isopropyl amine fractions of Wattakaka volubilis leaves.

OBJECTIVES: This study was carried out to investigate the impact of various isolated phytochemical components present in the Wattakaka volubilis leaves for the growth and proliferation of human osteoblast like cells (MG63). KEY FINDINGS: Ethyl acetate was found to be the best solvent for potential extraction of phytocompounds. Further, the MTT assay was carried out to deduce the viability of 44 isolated phytochemicals. Ten phytochemical fractions found to increase the cell growth were subjected to statistical tool namely Plackett-Burman and Central composite design to screen the optimum phytochemical fraction and its dosage. The active phytochemical constituents were analysed and identified as hexadeconoic acid, octadeconoic acid, N,N-diisopropyl(2,2,3,3,3-pentafluoropropyl)amine using GC-MS and HPLC techniques. The impact of optimized concentration was assessed on osteoblast cells. The maximum % cell viability, % DNA and collagen content were found to be 164.44, 159.32 and 3.81, respectively. CONCLUSIONS: The results confirmed that the optimized fraction containing decanoic acid and isopropyl amine at particular concentration stimulated the proliferation of human osteoblast (MG63) cells. Hence, the optimized concentration of this compound from W. volubilis may used for treatment of bone related injuries externally.

Development of in situ product removal strategies in biocatalysis applying scaled-down unit operations.

An experimental platform based on scaled-down unit operations combined in a plug-and-play manner enables easy and highly flexible testing of advanced biocatalytic process options such as in situ product removal (ISPR) process strategies. In such a platform, it is possible to compartmentalize different process steps while operating it as a combined system, giving the possibility to test and characterize the performance of novel process concepts and biocatalysts with minimal influence of inhibitory products. Here the capabilities of performing process development by applying scaled-down unit operations are highlighted through a case study investigating the asymmetric synthesis of 1-methyl-3-phenylpropylamine (MPPA) using ω-transaminase, an enzyme in the sub-family of amino transferases (ATAs). An on-line HPLC system was applied to avoid manual sample handling and to semi-automatically characterize ω-transaminases in a scaled-down packed-bed reactor (PBR) module, showing MPPA as a strong inhibitor. To overcome the inhibition, a two-step liquid-liquid extraction (LLE) ISPR concept was tested using scaled-down unit operations combined in a plug-and-play manner. Through the tested ISPR concept, it was possible to continuously feed the main substrate benzylacetone (BA) and extract the main product MPPA throughout the reaction, thereby overcoming the challenges of low substrate solubility and product inhibition. The tested ISPR concept achieved a product concentration of 26.5 gMPPA · L-1 , a purity up to 70% gMPPA · gtot-1 and a recovery in the range of 80% mol · mol-1 of MPPA in 20 h, with the possibility to increase the concentration, purity, and recovery further. Biotechnol. Bioeng. 2017;114: 600-609. © 2016 Wiley Periodicals, Inc.

Enantioseparation of benzofurys and other novel psychoactive compounds by CE and sulfobutylether ß-cyclodextrin as chiral selector added to the BGE.

The illicit drug market of psychoactive substances for human abuse is continuously expanding and developing. Besides already known substance classes like cathinones, amphetamines or synthetic cannabinoids, further derivatives such as benzofurys, thiophenes, and structural analogues of methylphenidate entered the global market recently. As many of these new compounds contain a stereogenic centre it is supposed that their isomers may differ in their pharmacological effects as it is the case with amphetamines or several chiral active pharmaceutical ingredients, for instance. In the course of this study, a method for the chiral separation of a set of 16 recreational drugs by CE was developed. The aim was to separate the analytes into their enantiomers at equal conditions within short time. Sulfobutylether ß-cyclodextrin served as chiral selector in an aqueous ammonium acetate solution containing ACN. For method optimization, methedrone and ethylphenidate were used as model compounds to find the appropriate concentration of chiral selector. Moreover, the influence of the pH value on enantioseparation was tested. Fourteen or 16 mM sulfobutylether ß-cyclodextrin, 50 mM ammonium acetate solution (pH 4.5) with 10% ACN were found to be optimal for enantioseparation of seven benzofurys, four cathinones, two diphenidines, ethylphenidate, methiopropamine, and thiothinone. Most of them were baseline resolved at migration times below 25 min.

Chemical analysis of bleach and hydroxide-based solutions after decontamination of the chemical warfare agent O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX).

Detailed chemical analysis of solutions used to decontaminate chemical warfare agents can be used to support verification and forensic attribution. Decontamination solutions are amongst the most difficult matrices for chemical analysis because of their corrosive and potentially emulsion-based nature. Consequently, there are relatively few publications that report their detailed chemical analysis. This paper describes the application of modern analytical techniques to the analysis of decontamination solutions following decontamination of the chemical warfare agent O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX). We confirm the formation of N,N-diisopropylformamide and N,N-diisopropylamine following decontamination of VX with hypochlorite-based solution, whereas they were not detected in extracts of hydroxide-based decontamination solutions by nuclear magnetic resonance (NMR) spectroscopy or gas chromatography-mass spectrometry. We report the electron ionisation and chemical ionisation mass spectroscopic details, retention indices, and NMR spectra of N,N-diisopropylformamide and N,N-diisopropylamine, as well as analytical methods suitable for their analysis and identification in solvent extracts and decontamination residues.

Simultaneous solid phase extraction and derivatization of aliphatic primary amines prior to separation and UV-absorbance detection.

To overcome the problem of poor sensitivity of capillary electrophoresis-UV absorbance for the detection of aliphatic amines, a solid phase extraction and derivatization scheme was developed. This work demonstrates successful coupling of amines to a chromophore immobilized on a solid phase and subsequent cleavage and analysis. Although the analysis of many types of amines is relevant for myriad applications, this paper focuses on the derivatization and separation of amines with environmental relevance. This work aims to provide the foundations for future developments of an integrated sample preparation microreactor capable of performing simultaneous derivatization, preconcentration, and sample cleanup for sensitive analysis of primary amines.

A novel antimicrobial epoxide isolated from larval Galleria mellonella infected by the nematode symbiont, Photorhabdus luminescens (Enterobacteriaceae).

A novel antimicrobial epoxide, 2-isopropyl-5-(3-phenyl-oxiranyl)-benzene-1,3-diol (1), was identified from larval Galleria mellonella infected by a symbiotically associated bacterium-nematode complex (Photorhabdus luminescens C9-Heterorhabditis megidis 90). Its structure was determined with spectroscopic analysis and confirmed by chemical synthesis starting from a known antibiotic, 2-isopropyl-5-(2-phenylethenyl)-benzene-1,3-diol (2). Epoxide 1 was active against Bacillus subtilis, Escherichia coli, Streptococcus pyogenes, and a drug-resistant, clinical strain of Staphylococcus aureus (RN4220) with minimum inhibitory concentrations in the range of 6.25-12.5 microg/ml. Epoxide 1 was cytotoxic against human cancer cell lines, MCF-7 wt, H460, and Jurkat, with GI(50) of 2.14, 0.63, and 0.42 microM, respectively, but was less toxic on normal, mouse splenic lymphocytes with a GI(50) of 45.00 microM.

Chiral separation of pheniramine-like 3-phenyl-3-heteroarylpropylamines by CE and HPLC methods.

Analytical CE and HPLC methods were developed for the chiral separation of halogen-substituted 3-phenyl-3-(2-pyridyl)propylamines 1-4 (1: 3-(4-fluorophenyl) approximately, 2: 3-(3,4-difluorophenyl) approximately, 3: 3-(4-chlorophenyl) approximately, 4: 3-(3,4-dichlorophenyl) approximately ), 3-(4-fluorophenyl)-3-(2-thiazolyl)propylamine (5), and 3-(4-fluorophenyl)-3-(1-benzylimidazol-2-yl)propylamine (6), which are building blocks for the preparation of very potent arpromidine-type histamine H(2) receptor agonists. All amines were enantioseparated by CE with resolutions of at least 1.8 using alpha-, beta-, or gamma-cyclodextrin (CD) as chiral selectors. With heparin as buffer additive for CE the optical antipodes of 1-4 and 6 were separated with resolutions > or = 1.8. On RP-18 columns the separation of the (+)-(S)-acetylmandelic acid amides of racemic 2 (R = 0.9, alpha = 1.07) and the thioureas prepared by addition of 6 to 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate (R = 2.0, alpha = 1.20) was successful, whereas the diastereomeric ureas prepared from 3 and (+)-(S)-1-(1-naphthyl)ethyl isocyanate could not be resolved. Separation of the diastereomeric isoindoles prepared from 1-5, o-phthaldialdehyde and 2,3,4,6-tetra-O-acetyl-1-thio-beta-D-glucopyranoside was achieved on a RP-18 phase (R > or = 0.4, a > or = 1.02). Direct separation of the enantiomers of 3 and 4 was achieved on a Cyclobond I column (R > or = 0.9, alpha > or = 1.07). alpha- and beta-CD were also useful as mobile phase additives for HPLC (3 and 4: RP-18 column, beta-CD, R > or = 0.4, alpha > or = 1.03; 3: RP-18 column, alpha-CD: R = 0.5, alpha = 1.04).

Mololipids, a new series of anti-HIV bromotyramine-derived compounds from a sponge of the order verongida.

A new series of lipids called mololipids have been identified from an Hawaiian sponge of the order Verongida. The structures of these lipids was deduced from spectroscopic data of the lipid mixture combined with GC-MS analysis. The core of this novel series of lipids is a bromotyramine homoserine-derived moiety known as moloka'iamine (1) which is found in many Verongid sponge metabolites. Moloka'iamine forms bisamides with a diverse series of fatty acids and the mololipids mixture (2) was active against HIV-1 with an EC(50) of 52.2 microM without cytotoxicity in human lymphocytes (IC(50) > 100 microM).

Determination of amphetamine and related compounds in urine using on-line derivatization in octadecyl silica columns with 9-fluorenylmethyl chloroformate and liquid chromatography.

A method for the determination of amphetamine and related compounds in urine based on on-line derivatization with 9-fluorenylmethyl chloroformate (FMOC) and high-performance liquid chromatography is described. Derivatization is performed in a 20 x 2.1 mm I.D. column packed with a Hypersil ODS C18, 30 micron stationary phase, which is also used for sample clean-up and enrichment of the analytes. Next, the derivatized analytes are transferred to a LiChrospher 100 RP-C18 (5 micron, 125 x 4 mm I.D.) analytical column for their separation and quantification, using reversed-phase conditions and fluorescence detection. The described assay was applied to the determination of norephedrine, ephedrine, pseudoephedrine, amphetamine, phenylpropylamine and methamphetamine at concentrations of 0.5-10.0 micrograms/ml. Analyte conversions were about 55-96% of those obtained by the off-line derivatization mode under similar conditions, resulting in limits of detection in the 5-25 ng/ml range.

Gas chromatographic analysis of bacterial amines as their free bases.

Columns of Chromosorb 103, Tenax-GC, Amine 220 plus potassium hydroxide on Chromosorb W, and Carbowax 20M plus potassium hydroxide on Chromosorb W were compared for their ability to separate bacterial amines as their free bases in aqueous solution. A 1.52 m X 0.6 cm O.D. column of Chromosorb 103 separated eleven amines when operated isothermally at 185 degrees C. A further four high-boiling amines could be separated at 240 degrees C. The other packings separated only eight amines isothermally, except for Tenax-GC which separated seven of the free bases. Chromosorb 103 performed less well than Carbowax 20 M plus potassium hydroxide with respect to number of plates or peak resolution. The maximum number of amines separated, thirteen, required Chromosorb 103 programmed from 170 degrees C to 230 degrees C at 3 degrees C min-1 after an initial holding time of 20 min. It was possible tentatively to identify amines in culture supernatant fluid of Proteus mirabilis, viz. ethylamine, isobutylamine and isoamylamine, after direct injection of culture supernatant fluid.

Resolution and absolute configuration of trans-2-(2,5-dimethoxy-4-methylphenyl)cyclopropylamine, a potent hallucinogen analogue.

An hallucinogen analogue, trans-2-(2,5-dimethoxy-4-methylphenyl)cyclopropylamine (DMCPA), was resolved into ints two enantiomers by fractional crystallization of salts with d- or l-O,O-dibenzoyltartaric acid. A comparison of the ORD and CD curves of the N-5-bromosalicylidene derivatives of trans-2-phenylcyclopropylamine of known absolute configuration and of the title compound established the stereochemistry of the latter to be (1R,2S)-(-) and (1s,2r)-(+). We have earlier shown that the (-) isomer shows selective behavioral effects in cats and mice. In present study it was found that the (-) isomer selectively elicits rabbit hyperthermia when compared with the (+) isomer. In view of the stereoselective ability of the (-) isomer to elicit hallucinogen-like behavioral profiles in these animal models, the proof of absolute configuration lends further support to a new model which interrelates the active binding, conformation of phenethylamine hallucinogens to that of serotonin and tryptamines.

Thin layer chromatographic identification of some sympathomimetic amines.

Thin layer chromatographic behavior of some sympathomimetic amines in the presence of acids in neutral and organic solvent systems is reported. The sympathomimetic amines were dissolved in 0.1N HCl or ethanol and treated with bromocresol green or p-nitrobenzoyl chloride reagents on fiber sheets or precoated glass plates. Two-, 3-, and 4-, component solvent systems were tested. Benzene-ethyl acetate gave 2 spots for each amine standard; the more polar spots were satisfactorily separated. Amines in pharmaccuticals were not separated by any solvent system tested.

Isolation of S-adenosyl-3-thiopropylamine from the eye of the sea catfish (Arius felis).

A method is reported for the separation of S-adenosyl-3-methylthiopropylamine and other basic compounds in the eye of the sea catfish (Arius felis) by ion-exchange chromatography on CM-Sephadex. One of the basic compounds was isolated in crystalline form and was shown to be S-adenosyl-3-thiopropylamine by chemical and spectroscopic characterizations and by comparison with a synthetic sample.