| Volatile organic compounds?VOCs?come in a wide variety and distributed widely.Acetone,n-propanol,epichlorohydrin and acrylonitrile are four common toxic VOCs gases in living and industrial environments,which seriously endanger the natural environment and human health,the realization of high sensitivity detection of these VOCs gases is one of the hotspots in the field of environmental analysis in recent years.Cataluminescence as an important detection method for chemiluminescence analysis,and has the characteristics of high sensitivity,simple operation,and real-time real-time monitoring,and the catalytic material involved is the core component of the cataluminescence sensor.As a important catalytic material,alkaline earth metal oxides are cheap,high catalytic,and environmentally friendly.Our study of this paper has found that some typical VOCs gases,such as acetone,n-propanol,epichlorohydrin and acrylonitrile,can produce strong chemiluminescence phenomenon on the surface of the alkaline earth metal oxide,passed the optimization of the experimen,and designed four types of cataluminescence VOCs sensor,and established a new method for detecting these VOCs.The effectiveness of each sensor was further evaluated:1.Based on the fact that acetone has cataluminescence phenomenon on CaO surface,a sensor was designed and fabricated to detect acetone gas in air.The linear range of cataluminescence intensity versus acetone concentration was from 7.6 to 1520mg/m3?R=0.9984?with a detection limit of 1.52 mg/m3?S/N=3?,under the optimal conditions of 535 nm wavelength at 266°C with a flow rate of 400 mL/min.Some volatile organic compounds?VOC?were also explored as interference test,like ethanol,benzene,dimethylbenzene,methanol,acrylonitrile,acetonitrile,methanol,cyclohexanol,glycol,dichlorobutane,isoamylol,and n-butanol.Acrylonitrile,acetonitrile and methanol had interferences less than 8.9%,4.2%,2.5%,respectively.Other organics possessed no obvious influences to the detection with interferences less than 1.0%,showing excellent selectivity of the as-prepared sensor.Moreover,cataluminescence intensity was nearly unchangeable to continuously detect 304 mg/m3 acetone for 48 h with the relative standard deviation?RSD?of 3.65%for 20 circles,exhibiting its perfect stability and service life.2.Based on the strong luminescence of n-propanol on the surface of MgO materials,n-propanol gas was determined under the optimum experimental conditions of wavelength 460 nm,temperature 298°C and airflow velocity 540 mL/min.The liner range of cataluminescence intensity versus n-propanol concentration was 140640mg/m3,and the detection limits was 4.22 mg/m3.In order to determine the selectivity of MgO materials to n-propanol gas,Nine gases were selected for interference test.The interference rate of n-butanol and ethanol on n-propanol was 3%,and there was no interference in other gases.Therefore,MgO materials had better selectivity for n-propanol gas.After 40 h of continuous used of n-propanol gas in 160 mg/m3,the luminescence intensity did not change obviously,which indicated that the sensor also had a good service life.3.A cataluminescence sensor using composite MgO/SiO2 as material for the determination of epichlorohydrin in air was developed.At the wavelength of 420 nm,at314°C and the air flow rate of 300 mL/m3,the linear range of detection for epichlorohydrin was 6960 mg/m3,and the detection limit was 3 mg/m3.The interference of 9 VOCs with epichlorohydrin was investigated.The interference rates of ethanol,dichloropropane and ether were 6.4%,3.6%,2.3%,and the other VOCs had no influence on epichlorohydrin detection.4.A cataluminescence sensor using composite CaO/MgO as material for the determination of acrylonitrile in air was developed.Under the optimum experimental conditions,a good linear relationship was obtained in the concentration range of 15750mg/m3 for acrylonitrile,and the detection limit was 0.5 mg/m3.The luminescence response of nine kinds of VOCs which might co-exist with acrylonitrile was studied.The interference rates of methanol,n-propanol and toluene on acrylonitrile were 14.3%,3.4%and 1.9%,and the other VOCs had no influence on epichlorohydrin detection. |
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