Five different quorum sensing peptides(QSP) were iodinated using different iodination techniques. These iodinated peptides were analyzed using a C18 reversed phase HPLC system, applying a linear gradient of water and ...Five different quorum sensing peptides(QSP) were iodinated using different iodination techniques. These iodinated peptides were analyzed using a C18 reversed phase HPLC system, applying a linear gradient of water and acetonitrile containing 0.1%(m/v) formic acid as mobile phase. Electrospray ionization(ESI)ion trap mass spectrometry was used for the identification of the modified peptides, while semi-quantification was performed using total ion current(TIC) spectra. Non-iodinated peptides and mono-and diiodinated peptides(NIP, MIP and DIP respectively) were well separated and eluted in that order. Depending on the used iodination method, iodination yields varied from low(2%) to high(57%).展开更多
The availability of liquid chromatography ultraviolet nuclear magnetic resonance mass spectrometry (LC UV NMR MS)integrated systems is providing greater information content and confidence for a variety of sample types...The availability of liquid chromatography ultraviolet nuclear magnetic resonance mass spectrometry (LC UV NMR MS)integrated systems is providing greater information content and confidence for a variety of sample types, such asdrug metabolites, natural products, impurities, and degradants. A wide range of experimental strategies can be pur sued,highlighting the flexibility and performance possible with this multihyphenated technique.展开更多
Direct photochemical degradations of progesterone (PR) and testosterone (TR), two naturally produced hormones, have been conducted in non-buffered aqueous solution (pH ranging between 5.5 and 6.0). The irradiation exp...Direct photochemical degradations of progesterone (PR) and testosterone (TR), two naturally produced hormones, have been conducted in non-buffered aqueous solution (pH ranging between 5.5 and 6.0). The irradiation experiments were carried out in a batch reactor upon monochromatic (254 nm) and polychromatic (λ > 290 nm) at 25°C. GLC/MS and LC/UV-DAD/MS analyses were performed to investigate phototransformation products after a solid phase extraction (SPE) step for analytes concentration. For each compound several by-products have been identified and are the same ones under both irradiation conditions. Because of the presence of the same chromophore (α, β-unsaturated group) absorbing UV radiations in both hormones, the majority of chromatographic peaks correspond to by-products formed according to identical mechanisms involving isomerization, enolization, oxidation and hydration to lead to the generation of lumiketone, cyclopentenone, spiro-hydration, oxidation and hydroxylation photoproducts.展开更多
基金the‘Research Foundation–Flanders(FWO)’(Grant no.1S21017N to Nathan Debunne)the‘Institute for the Promotion of Innovation through Science and Technology in Flanders(IWT-Vlaanderen)’(Grant no.131356 to Frederick Verbeke)
文摘Five different quorum sensing peptides(QSP) were iodinated using different iodination techniques. These iodinated peptides were analyzed using a C18 reversed phase HPLC system, applying a linear gradient of water and acetonitrile containing 0.1%(m/v) formic acid as mobile phase. Electrospray ionization(ESI)ion trap mass spectrometry was used for the identification of the modified peptides, while semi-quantification was performed using total ion current(TIC) spectra. Non-iodinated peptides and mono-and diiodinated peptides(NIP, MIP and DIP respectively) were well separated and eluted in that order. Depending on the used iodination method, iodination yields varied from low(2%) to high(57%).
文摘The availability of liquid chromatography ultraviolet nuclear magnetic resonance mass spectrometry (LC UV NMR MS)integrated systems is providing greater information content and confidence for a variety of sample types, such asdrug metabolites, natural products, impurities, and degradants. A wide range of experimental strategies can be pur sued,highlighting the flexibility and performance possible with this multihyphenated technique.
文摘Direct photochemical degradations of progesterone (PR) and testosterone (TR), two naturally produced hormones, have been conducted in non-buffered aqueous solution (pH ranging between 5.5 and 6.0). The irradiation experiments were carried out in a batch reactor upon monochromatic (254 nm) and polychromatic (λ > 290 nm) at 25°C. GLC/MS and LC/UV-DAD/MS analyses were performed to investigate phototransformation products after a solid phase extraction (SPE) step for analytes concentration. For each compound several by-products have been identified and are the same ones under both irradiation conditions. Because of the presence of the same chromophore (α, β-unsaturated group) absorbing UV radiations in both hormones, the majority of chromatographic peaks correspond to by-products formed according to identical mechanisms involving isomerization, enolization, oxidation and hydration to lead to the generation of lumiketone, cyclopentenone, spiro-hydration, oxidation and hydroxylation photoproducts.
