Sha Y.,Corporation Technical Center |
Meng J.,Fudan University |
Zhang Y.,Corporation Technical Center |
Deng C.,Fudan University |
Wu D.,Corporation Technical Center
Journal of Separation Science | Year: 2010
In this work, the novel technique based on headspace single-drop microextraction with insyringe derivatization followed by GC-MS was established to determine the volatile organic acids in tobacco. The parameters for headspace single-drop microextraction and in-syringe derivatization were optimized, including extraction time, and volume of derivatization reagent and in-syringe derivatization time. The method validations including linearity, precision, recovery and LOD were also studied. The obtained results illustrated that the optimized technique was easy, highly efficient and sensitive. Finally, the proposed method was successfully applied to the analyses of volatile organic acids in tobacco samples with seven different brands. It was further demonstrated that the present technique developed in this study does offer a simple and fast approach to determine volatile organic acids in tobacco. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA.
Zhang D.-P.,Jiangsu University |
Yuan Y.-N.,Nantong University |
Du J.-Y.,Jiangsu University |
Xu Y.,Enterprise Technical Center |
Ji L.-R.,Enterprise Technical Center
Neiranji Xuebao/Transactions of CSICE (Chinese Society for Internal Combustion Engines) | Year: 2012
Using the Eulerian gas equation and Lagrangian drop equation, a simulation model of intake injecting methanol for a diesel engine with helical port-valve-cylinder was proposed. The model consists of liquid droplet break-up, evaporation, collision and coalescence, as well as wall interaction of liquid droplets and wall film separation and valve seat liquid expelling. Methanol and air mixing process for methanol injected into the engine intake port was simulated to guide the methanol/diesel dual fuel engine modification. Bench test of the dual fuel engine shows that the cylinder pressure of model calculation is good agreement with that of experiment. Methanol injection timing directly affects the cyclic amount of methanol into cylinder. Methanol injection during inlet valve closed will be more readily atomized and mixed in the induction stroke. Methanol injection orientation is determined by the principle of decreasing methanol film on cold wall. Methanol concentration in cylinder is stratified more obviously in cylinder axis direction than that in cylinder radial direction.