A NITRITE MICROSENSOR FOR PROFILING ENVIRONMENTAL BIOFILMS

Citation
D. Debeer et al., A NITRITE MICROSENSOR FOR PROFILING ENVIRONMENTAL BIOFILMS, Applied and environmental microbiology, 63(3), 1997, pp. 973-977
Citations number
35
Categorie Soggetti
Microbiology,"Biothechnology & Applied Migrobiology
ISSN journal
00992240
Volume
63
Issue
3
Year of publication
1997
Pages
973 - 977
Database
ISI
SICI code
0099-2240(1997)63:3<973:ANMFPE>2.0.ZU;2-E
Abstract
A highly selective liquid membrane nitrite microsensor based on the hy drophobic ion-carrier aquocyano-cobalt(III) -hepta(2-phenylethyl)-cobr ynate is described, The sensor has a tip diameter of 10 to 15 mu m. Th e response is log-linear in freshwater down to 1 mu M NO2- and in seaw ater to 10 mu M NO2-. A method is described for preparation of relativ ely large polyvinyl chloride (PVC)-gelled liquid membrane microsensors with a tip diameter of 5 to 15 mu m, having a hydrophilic coating on the tip, The coating and increased tip diameter resulted in more sturd y sensors, with a lower detection limit and a more stable signal than uncoated nitrite sensors with a tip diameter of 1 to 3 mu m. The coati ng protects the sensor membrane from detrimental direct contact with b iomass and can be used for all PVC-gelled liquid membrane sensors mean t for profiling microbial mats, biofilms, and sediments. Thanks to the se improvements, liquid membrane sensors can now be used in complex en vironmental samples and in situ, e.g., in operating bioreactors. Examp les of measurements in denitrifying, nitrifying, and nitrifying/denitr ifying biofilms from wastewater treatment plants are shown. In all of these biofilms high nitrite concentrations were found in narrow zones of less than 1 mm.