A new sensor material for monitoring pH in aqueous solutions is described. It is based on lipophilic ion pairs consisting of an anionic pH indicator Bromocresol Green and a quaternary ammonium cation cetyltri-methylam...A new sensor material for monitoring pH in aqueous solutions is described. It is based on lipophilic ion pairs consisting of an anionic pH indicator Bromocresol Green and a quaternary ammonium cation cetyltri-methylammonium. The ion pairs are homogeneously distributed inside the plasticized PVC membrane. The change of pH in an aqueous solution causes the change of optical property of the indicator immobilized on the plasticized PVC membrane. The plasticized PVC membrane is sensitive in a pH range from 4.0 to 6.0.展开更多
Capillary electrochromatography (CEC) is a hybrid technique that couples the good selectivity of high-performance liquid chromatography (HPLC) and the high separation efficiency of capillary electrophoresis (CE)...Capillary electrochromatography (CEC) is a hybrid technique that couples the good selectivity of high-performance liquid chromatography (HPLC) and the high separation efficiency of capillary electrophoresis (CE). Both charged and uncharged compounds can be separated effectively using CEC. In some cases, however, the bubbles that generated in the capillary column in pure CEC performed on commercial CE instruments will cause unstable current and even disrupt the separation when the concentration of buffer is very high. By applying pressure on the electrochromatographic separation via a micro-HPLC pump, pressurized capillary electrochromatography ( pCEC ) combines two driving factors of the electroosmotic flow (EOF) and the pressure flow, thereby increasing the speed and the selectivity of separation and suppressing the bubble formation. Moreover,展开更多
基金Supported by Foundation for University Key Teacher by the MOE,the Natural Science Foundation of Fujian Provinceof China(No.D9910 0 0 9) ,Three Projects of Science and Technology of Fujian Province(No.K990 37)
文摘A new sensor material for monitoring pH in aqueous solutions is described. It is based on lipophilic ion pairs consisting of an anionic pH indicator Bromocresol Green and a quaternary ammonium cation cetyltri-methylammonium. The ion pairs are homogeneously distributed inside the plasticized PVC membrane. The change of pH in an aqueous solution causes the change of optical property of the indicator immobilized on the plasticized PVC membrane. The plasticized PVC membrane is sensitive in a pH range from 4.0 to 6.0.
基金Supported by the National Natural Science Foundation of China(Nos 20305004 and 20575012), Program for NewCentury Ex-cellent Talents in University of China(No NCET-04-0612), Specialized Research Fund for the Doctoral Program of Higher Education(No 20050386008), and the Science Foundation of Fujian Province(Nos 2005Y015 and D0510006)
文摘Capillary electrochromatography (CEC) is a hybrid technique that couples the good selectivity of high-performance liquid chromatography (HPLC) and the high separation efficiency of capillary electrophoresis (CE). Both charged and uncharged compounds can be separated effectively using CEC. In some cases, however, the bubbles that generated in the capillary column in pure CEC performed on commercial CE instruments will cause unstable current and even disrupt the separation when the concentration of buffer is very high. By applying pressure on the electrochromatographic separation via a micro-HPLC pump, pressurized capillary electrochromatography ( pCEC ) combines two driving factors of the electroosmotic flow (EOF) and the pressure flow, thereby increasing the speed and the selectivity of separation and suppressing the bubble formation. Moreover,