Footprint of carbonyl compounds in hand scent by in-tube solid-phase microextraction coupled to nano-liquid chromatography/diode array detection.

In the present work, the footprint of carbonyl compounds in hand scent was achieved by a miniaturized method consisting of sampling with cotton gauze, extraction and derivatization using 2,4-dinitrophenylhydrazine (DNPH) and preconcentration, separation and detection by in-tube solid-phase microextraction (IT-SPME) coupled to nano-liquid chromatography/Uv-vis diode array detection. The coupling IT-SPME-nanoLC-DAD was solved by using a two-valve system: the first valve for loading the sample and the second one to perform IT-SPME. To this aim, a nanoparticle-based capillary column was employed. Firstly, the transfer time from the load loop to the NP-based capillary column in the IT-SPME system was optimized. Additionally, the conditioning and clean-up steps were also studied. For the chromatographic separation of DNPH derivatives, gradient elution mode (acetonitrile/water) and a C18 nanocolumn were employed. The detection limits achieved were between 0.5 and 1.5 µg/L and % rsd was lower than 5% for quantification limits. The proposed methodology gave rise to different chromatographic profiles of carbonyl compounds in the hand scent of several volunteers. These profiles were obtained by estimating the relative peak area of selected carbonyls in hand scent. Nonanal, decanal and dodecanal and other low polarity carbonyl compounds (unknown hydrazones) were detected in the odor profiles.

Solid-phase extraction combined with dispersive liquid-liquid microextraction, fast derivatisation and high performance liquid chromatography-tandem mass spectrometry analysis for trace determination of short-chained dodecyl alcohol ethoxylates and dodecyl alcohol in environmental water samples.

A new method was developed for preconcentration, derivatisation and analysis of short-chained dodecyl alcohol ethoxylates and dodecyl alcohol. Solid-phase extraction combined with dispersive liquid-liquid microextraction was used for preconcentration of target compounds. Several parameters were optimised including different solid phase extraction sorbents, type and volume of both extracting and dispersive solvents. As a result fast and relatively simple preconcentration method was developed. The analytes were preconcentrated 700 times with the use of small sample volume. The target compounds were derivatised before analysis with the use of newly developed procedure. The derivatisation procedure was made in vial insert and was performed at room temperature with the use of 1-naphthoyl chloride as the derivatisation agent. The developed method was used for the analysis of short-chained dodecyl alcohol ethoxylates and dodecyl alcohol in both sewage effluent from sewage treatment plants and river water samples.

(2S,3R)-2-aminododecan-3-ol, a new antifungal agent from the ascidian Clavelina oblonga.

A new antifungal agent, (2S,3R)-2-aminododecan-3-ol (1), has been isolated from the ascidian Clavelina oblonga collected in Brazil. The structure of 1 was established by analysis of spectroscopic data, including absolute stereochemistry determined by circular dichroism analysis of the dibenzoyl derivative 2. Compound 1 displayed antifungal activity against Candida albicans ATCC 10231 with a MIC of 0.7 mug/mL and against Candida glabrata with a MIC of 30 microg/mL.

Chlorinated C12 fatty acid metabolites from the red alga Gracilaria verrucosa.

Three compounds containing moieties rarely encountered in nature, viz., 3-nonyloxirane-2 carboxylic acid methyl ester (1), 2-chlorododec-2-en-1-ol (2), and 2-chlorododec-2,11-dien-1-ol (3), were isolated from the red alga Gracilaria verrucosa, and their structures were determined by spectroscopic methods.

Purification, identification, concentration and bioactivity of (Z)-7-dodecen-1-yl acetate: sex pheromone of the female Asian elephant, Elephas maximus.

In their natural ecosystems, adult male and female Asian elephants, Elephas maximus, live separately. For several weeks prior to ovulation, female elephants release a substance in their urine which elicits a high frequency of non-habituating chemosensory responses, especially flehmen responses, from male elephants. These responses occur prior to, and are an integral part of, mating. Using bioassay-guided fractionation, quantitatively dependent on these chemosensory responses, a specific sex pheromone was isolated and purified by an alternating series of organic and/or aqueous extractions, column chromatography, gas chromatography and high-performance liquid chromatography. Using primarily 1H-proton nuclear magnetic resonance (NMR) spectrometry and gas chromatography-mass spectrometry (GC-MS) of the urine-derived pheromone and its dimethyl disulfide derivative, we determined the structure of the active compound to be (Z)-7-dodecen-1-yl acetate (Z7-12:Ac). Concentrations of Z7-12:Ac in the female urine increased from non-detectable during the luteal phase to 0.48 microgram/ml (0.002 mM) early in the follicular phase and to 33.0 micrograms/ml (0.146 mM) just prior to ovulation. Bioassays with commercially available authentic synthetic Z7-12:Ac, using 10 Asian male elephants at several locations in the US, demonstrated quantitatively elevated chemosensory responses that were robust during successive tests, and several mating-associated behaviors. Bioassays with Z7-12:Ac with adult male elephants dwelling in more natural social situations in forest camps in Myanmar revealed some differing contextual pre-mating behavioral components. The remarkable convergent evolution of this compound suggests that compounds identified in mammalian exudates that are also present in pheromone blends of insects should be re-evaluated as potential mammalian chemosignals.