Design of Efficient Zeolite Sensor Materials for n-Hexane
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- 作者：Ping Yang ; Xingnan Ye ; Choiwan Lau ; Zengxi Li ; Xia Liu ; Jianzhong Lu
- 刊名：Analytical Chemistry
- 出版年：2007
- 出版时间：February 15, 2007
- 年：2007
- 卷：79
- 期：4
- 页码：1425 - 1432
- 全文大小：527K
- 年卷期：v.79,no.4(February 15, 2007)
- ISSN：1520-6882
文摘
The effectiveness of several zeolite catalysts was investigated using the cataluminescence (CTL) gas sensor system. Trace amounts of n-hexane in air samples weredetected by this method. This research establishes thatthe specific pore size of the zeolite offers designableenvironment for selective CTL reaction, and "Lewis-type"basic sites appear to contribute to the catalytic nature ofthe zeolite surface. By incorporating either Cs+ or K+, thevelocity and luminescence intensity of these catalyticreactions increase while going from Na to Cs, accordingto the basic nature of this group of cations in the followingorder: Cs > K > Na. The proposed sensor shows highsensitivity and selectivity to n-hexane at a mild reactiontemperature of 225 
C. Quantitative analysis was performed at a selected wavelength of 460 nm. The linearrange of CTL intensity versus concentration of n-hexanewas 0.776-23.28 
g/mL (R = 0.997, n = 7) on CsNaY,and 0.776-23.28 g/mL (R = 0.998, n = 7) on CsNaX,with a detection limit of 0.155 g/mL (signal-to-noise ratio3). Interferences from foreign substances such as methanol, ethanol, 2-propanol, acetone, acetonitrile, chloroform, or dichlormethane and other alkanes, aromatics,and alkyl aromatics such as methane, n-pentane, 3-methylpentane, 3,3-dimethylpentane, methylbenzene, ethylbenzene, and sec-butylbenzene were very low or notdetectable. Results of a series of GC and GC/MS experiments suggest that the possible mechanism of the reactionis the formation of an unstable transition structure with afour-member ring, and this ring most probably consistsof an oxygen atom and a carbonium ion localized on thezeolite suface.
C. Quantitative analysis was performed at a selected wavelength of 460 nm. The linearrange of CTL intensity versus concentration of n-hexanewas 0.776-23.28 g/mL (R = 0.997, n = 7) on CsNaY,and 0.776-23.28 g/mL (R = 0.998, n = 7) on CsNaX,with a detection limit of 0.155 g/mL (signal-to-noise ratio3). Interferences from foreign substances such as methanol, ethanol, 2-propanol, acetone, acetonitrile, chloroform, or dichlormethane and other alkanes, aromatics,and alkyl aromatics such as methane, n-pentane, 3-methylpentane, 3,3-dimethylpentane, methylbenzene, ethylbenzene, and sec-butylbenzene were very low or notdetectable. Results of a series of GC and GC/MS experiments suggest that the possible mechanism of the reactionis the formation of an unstable transition structure with afour-member ring, and this ring most probably consistsof an oxygen atom and a carbonium ion localized on thezeolite suface.