Advanced online monitoring of cell culture off-gas using proton transfer reaction mass spectrometry.

Mass spectrometry has been frequently applied to monitor the O₂ and CO₂ content in the off-gas of animal cell culture fermentations. In contrast to classical mass spectrometry the proton transfer reaction mass spectrometry (PTR-MS) provides additional information of volatile organic compounds by application of a soft ionization technology. Hence, the spectra show less fragments and can more accurately assigned to particular compounds.

Oxidative quenching within photosensitizer-acceptor dyads based on bis(bidentate) phosphine-connected osmium(II) bipyridyl light absorbers and reactive metal sites.

For the first time oxidative quenching of OsPN chromophores by reactive Pt or Pd sites containing , , -1,2,3,4-tetrakis(diphenylphosphino)cyclobutane (dppcb) is directly observed despite the presence of a saturated cyclobutane backbone "bridge". This dramatic effect is measured as a sudden temperature-dependent onset of a reduction in phosphorescence lifetime in [Os(bpy)(dppcb)MCl](SbF) (M = Pt, ; Pd, ). The appearance of this additional energy release is not detectable in [Os(bpy)(dppcbO)](PF) (), where dppcbO is , , -1,2-bis(diphenylphosphinoyl)-3,4-bis(diphenylphosphino)cyclobutane.

First observation of a potential non-invasive breath gas biomarker for kidney function.

We report on the search for low molecular weight molecules-possibly accumulated in the bloodstream and body-in the exhaled breath of uremic patients with kidney malfunction. We performed non-invasive analysis of the breath gas of 96 patients shortly before and several times after kidney transplantation using proton-transfer-reaction mass spectrometry (PTR-MS), a very sensitive technique for detecting trace amounts of volatile organic compounds. A total of 642 individual breath analyses which included at least 41 different chemical components were carried out.

Implementation of proton transfer reaction-mass spectrometry (PTR-MS) for advanced bioprocess monitoring.

We report on the implementation of proton transfer reaction-mass spectrometry (PTR-MS) technology for on-line monitoring of volatile organic compounds (VOCs) in the off-gas of bioreactors. The main part of the work was focused on the development of an interface between the bioreactor and an analyzer suitable for continuous sampling of VOCs emanating from the bioprocess. The permanently heated sampling line with an inert surface avoids condensation and interaction of volatiles during transfer to the PTR-MS.

Surprising photochemical reactivity and visible light-driven energy transfer in heterodimetallic complexes.

The bis(bidentate) phosphine cis,trans,cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane (dppcb) has been used for the synthesis of a series of novel heterodimetallic complexes starting from [Ru(bpy)(2)(dppcb)]X(2) (1; X = PF(6), SbF(6)), so-called dyads, showing surprising photochemical reactivity. They consist of [Ru(bpy)(2)](2+)"antenna" sites absorbing light combined with reactive square-planar metal centres. Thus, irradiating [Ru(bpy)(2)(dppcb)MCl(2)]X(2) (M = Pt, 2; Pd, 3; X = PF(6), SbF(6)) dissolved in CH(3)CN with visible light, produces the unique heterodimetallic compounds [Ru(bpy)(CH(3)CN)(2)(dppcb)MCl(2)]X(2) (M = Pt, 7; Pd, 8; X = PF(6), SbF(6)).

Regio- and chemoselective oxidation of the bis(bidentate) phosphine cis,trans,cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane via cobalt(II) mediated dioxygen activation.

The bis(bidentate) phosphine cis,trans,cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane (dppcb) has been regioselectively oxidized leading to novel, hemilabile ligands. [Co2Cl4(dppcb)] (1a) is transformed via cobalt(II) mediated dioxygen activation into [Co2Cl4(2,3-trans-dppcbO2)] (2a) in excellent yield, where 2,3-trans-dppcbO2 is cis,trans,cis-2,3-bis(diphenylphosphinoyl)-1,4-bis(diphenylphosphino)-cyclobutane. By contrast, the in situ presence of dioxygen during the synthesis of Co2Br4(dppcb)] (1b) produces both [Co2Br4(2,3-trans-dppcbO2)] (2b) and [Co2Br4(1,3-trans-dppcbO2)] (3), where 1,3-trans-dppcbO2 is cis,trans,cis-1,3-bis(diphenylphosphinoyl)-2,4-bis(diphenylphosphino)-cyclobutane.

On the use of Tedlar® bags for breath-gas sampling and analysis.

The storage capability of Tedlar® bags for gaseous compounds was assessed using on-line proton-transfer-reaction mass spectrometry (PTR-MS). Sample bags were filled with a mixture of volatile organic compounds (VOCs) at known quantities in the ppbv range. The test gas included alcohol, nitrile, aldehyde, ketone, terpene and aromatic compounds.

3,6-Dihydroxy-2-(11-phenylundecanoyl)cyclohex-2-en-1-one from Virola venosa bark.

The structure of the title compound, C23H32O4, an arylalkanone isolated from the petroleum ether fraction of the ethanol extract of the bark of Virola venosa, has been established by NMR spectroscopy and, for the first time, by X-ray structure analysis. Two independent molecules of the same enantiomer are present in the unit cell. Both molecules exhibit an intramolecular hydrogen bond, which can be correlated with a rare signal observed at 18.