Development of a simple method for biotoxicity measurement using ultramicroelectrode array under non-deaerated condition.

In this paper, a mediated method by using ferricyanide under non-deaerated condition for biotoxicity measurement was proposed. Ultramicroelectrode array (UMEA) was employed for effectively amplify the electrochemical signal from the total limiting currents to distinguish a little change in toxicity. Five species of microorganisms including two bacilli (Escherichia coli and Enterobacter cloacae), two pseudomonas (Pseudomonas fluorescens and Pseucomonas putida) and one fungus (Trichosporon cutaneum) were employed. 3,5-dichlorophenol (DCP) was taken as the reference toxicant. The IC50 values we obtained were similar with the values obtained using in the deaerated method. E. coli was used as model test microorganism. The final concentration of ferricyanide is 45 mM, E. coli OD600 8 and 1 h incubation were taken in optimum conditions in this study. Four heavy metal ions (Cr(6+), Hg(2+), Cd(2+) and Bi(3+)) were examined under the optimum conditions. Comparison with the results reported previously has confirmed that this method provided a simple and rapid alternative to toxicity screening of chemicals, especially advantageous for in situ monitoring of water system.