Development of Biosensor in Detecting Ammonia

• Main Author: 林崇文
• Other Authors: 鄭武順
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/17261411101712640284

碩士 === 長庚大學 === 化學工程研究所 === 89 === Piezoelectric quartz crystal and biologically active enzyme were used in biosensor of high sensitivity.Utilizing enzyme’s specificity,it can adsorb specific gas.To immobilize the specific L-Glutamic Dehydrogenase of ammonia to quartz crystal,crosslinking reagents and others were used such as PEI、glutaraldehyde、glycine、NADH on the quartz crystal besides enzyme.The purpose of immobilizing glycine is that we want to cover exposed glutaraldehyde with glycine to reduce the interfering factor.However the addition of glycine reduced the activity of enzyme.We also immobilzed enzyme on the quartz crystal that contained NADH.NADH can’t increase enzyme’s adsorptive capacity but will increase the bonding of ammonia and make it difficult to desorb.PEI did not adsorb ammonia,but glutaraldehyde showed some adsorption of ammonia. Enzyme is hydrophilic.Its adsorption ability of moisture is more than ammonia.Because canister’s airtight function is better than sample bag, we use canister to fill gas and control humidity.Enzyme showed the largest quantity of adsorption of ammonia at RH=70.Under the best humid condition of adsorption,the specificity and enzyme’s adsorptive conditions for methylamine、ethylamine、CO2、acetone、ethanol、isoprene were studied.GLDH can adsob methylamine and ethylamine,but the quantity of adsorption of ammonia is more than methylamine and ethylamine. It’s not easy to desorb adsorbed methylamine and ethylamine.GLDH can also adsob a small amount of ethanol.The relation between the slope of adsorptive curve and ammonia’s concentration in gas phase within three minutes were studied. The following adsorption rate was obtainedR=aCb(a:0.0027,b:0.78).The quantity of adsorption for ammonia at different temperature was used to calculate the Langmuir adsorption isotherm.