Zlatev Roumen, Magnin Jean-Pierre, Ozil Patrick, Stoytcheva Margarita
Autonomous University of Baja California, Institute of Engineering, Blvd. Benito Juares S/N 21280 Mexicali, Baja California, Mexico.
Biosens Bioelectron. 2006 Feb 15;21(8):1493-500. doi: 10.1016/j.bios.2005.07.007. Epub 2005 Aug 10.
An amperometric bacterial sensor with current response to Fe(2+) and S(2)O(3)(2-) ions has been designed by immobilizing an acidophilic biomass of Acidithiobacillus ferrooxidans on a multi disk flat-front oxygen probe. The bacterial layer was located between the oxygen probe and a membrane of cellulose. A filtration technique was used to yield the bacterial membranes having reproducible activity. The decrease of O(2) flow across the bacterial layer is proportional to the concentration of the dosed species. The dynamic range appeared to be linear for the Fe(2+) ions up to 2.5 mmol L(-1) with a detection limit of 9 x 10(-7) mol L(-1) and a sensitivity of 0.25 A L mol(-1). The response of the biosensor is 84 s for a determination of 2 x 10(-4) mol L(-1) Fe(2+). Optimizing the Fe(2+) determination by A. ferrooxidans sensor was carried out owing to Design of Experiments (DOE) methodology and empirical modelling. The optimal response was thus obtained for a pH of 3.4, at 35 degrees C under 290 rpm solution stirring. S(2)O(3)(2-) concentration was determined at pH 4.7, so avoiding its decomposition. The concentration range was linear up to 0.6 mmol L(-1). Sensitivity was 0.20 A L mol(-1) with a response time of 207 s for a 2 x 10(-4) mol L(-1) S(2)O(3)(2-) concentration.
通过将嗜酸性氧化亚铁硫杆菌的生物质固定在多盘平面型氧探头上来设计一种对Fe(2+)和S(2)O(3)(2-)离子有电流响应的安培型细菌传感器。细菌层位于氧探头和纤维素膜之间。采用过滤技术制备具有可重复活性的细菌膜。穿过细菌层的O(2)流量的减少与所添加物质的浓度成正比。对于Fe(2+)离子，动态范围在高达2.5 mmol L(-1)时呈线性，检测限为9×10(-7) mol L(-1)，灵敏度为0.25 A L mol(-1)。对于2×10(-4) mol L(-1) Fe(2+)的测定，生物传感器的响应时间为84 s。基于实验设计（DOE）方法和经验建模对氧化亚铁硫杆菌传感器测定Fe(2+)进行了优化。因此，在35℃、溶液搅拌速度为290 rpm、pH为3.4的条件下获得了最佳响应。在pH 4.7下测定S(2)O(3)(2-)浓度，以避免其分解。浓度范围在高达0.6 mmol L(-1)时呈线性。对于2×10(-4) mol L(-1) S(2)O(3)(2-)浓度，灵敏度为0.20 A L mol(-1)，响应时间为207 s。
