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.