A study on the ignition process for the catalytic partial oxidation of methane to synthesis gas by MS-TPSR technique

The ignition processes for the catalytic partial oxidation of methane (POM) to synthesis gas over oxidic nickel catalyst (NiO/Al2O3), reduced nickel catalyst (Ni-0/Al2O3), and Pt-promoted oxidic nickel catalyst (Pt-NiO/Al2O3) were studied by the temperature-programmed surface reaction (TPSR) technique. The complete oxidation of methane usually took place on the NiO catalyst during the CH4/O-2 reaction, even with a pre-reduced nickel catalyst, and Ni-0 is inevitably first oxidized to NiO if the temperature is below the ignition temperature. It is above a certain temperature that Ni-0 is formed again, which leads to the start of the POM. The POM can be initiated at a much lower temperature on a Pt-NiO catalyst because of Pt promotion of the reduction of NiO. The POM in a fluidized bed can be easily initiated due to the addition of Pt.

Identification of ginsenosides in roots of Panax ginseng by HPLC-APCI/MS

A new HPLC-APCI/MS method for the identification of ginsenosides has been developed. The analyses were performed on a reversed-phase C-18 column using a binary eluent (acetonitrile and water) under gradient conditions. Although APCI is a high-temperature evaporative process, HPLC-APCI/MS could effectively identify thermo-labile ginsenosides. The [M-H](-) ions and the thermal degradation ions of ginsenosides could be clearly observed under negative and positive ion conditions, respectively, and these were used to identify the molecular masses, the aglycone structures and the sugar groups of ginsenosides. APCI/MS can provide more explicit information than ESI/MS for identifying and distinguishing ginsenosides. Using the HPLC-APCI/MS method, 35 ginsenosides were identified in Panax ginseng. Copyright (C) 2005 John Wiley & Sons, Ltd.