- Extractive hydrogenation: A new and versatile technique broadening gas chromatography applications
-
A new technique, "extractive hydrogenation", is combined with gas chromatography (GC) to analyze organic including biological samples. In this method, the sample (or an extract thereof) is subjected to intense hydrogenation under aqueous conditions in the presence of excess (in terms of mass) palladium/carbon catalyst. Products with a saturated hydrocarbon framework result, for example, as alcohols, the larger of which adsorb onto the carbon of the catalyst. These larger products are separately recovered by extracting the washed catalyst with an organic solvent and then detected by GC. Here, the GC was fitted with a flame ionization detector (FID) or an electron impact mass spectrometer (EI-MS). Detection in this way (H2-GC) of the following trace analytes was achieved: (a) 100 μg of an (acetylamino)fluorene-deoxyguanosine DNA adduct spiked into 1 mg of DNA; (b) 1.5 μg of novobiocin, an antibiotic, spiked into 15 mL of milk (followed by extraction prior to H2-GC); and (c) 1 mg of 4-aminobiphenyl, a carcinogen, spiked into 150 mg of hemoglobin (followed by hydrolysis prior to H2-GC). The technique gave somewhat different GC-FID chromatograms for Escherichia coli and Enterococcus bacteria. Unlike pyrolysis (similarly used prior to GC), which tends to convert a biological sample into a char, the hydrogenation technique turns the sample into a clear aqueous solution. Most importantly, the method brings a broad variety of organic-containing samples in a simple way into the scope of GC/EI-MS with its computerized library of spectra.
- Itani, Mohammad,Giese, Roger W.
-
-
Read Online
- A stable and practical nickel catalyst for the hydrogenolysis of C-O bonds
-
The selective hydrogenolysis of C-O bonds constitutes a key step for the valorization of biomass including lignin fragments. Moreover, this defunctionalization process offers the possibility of producing interesting organic building blocks in a straightforward manner from oxygenated compounds. Herein, we demonstrate the reductive hydrogenolysis of a wide variety of ethers including diaryl, aryl-alkyl and aryl-benzyl derivatives catalyzed by a stable heterogeneous NiAlOx catalyst in the presence of a Lewis acid (LA). The special feature of this catalyst system is the formation of substituted cyclohexanols from the corresponding aryl ether.
- Cui, Xinjiang,Yuan, Hangkong,Junge, Kathrin,Topf, Christoph,Beller, Matthias,Shi, Feng
-
p. 305 - 310
(2017/01/24)
-