An original bi-enzymatic biosensor was designed by immobilizing Arthrospira platensis cells, called Spirulina, on gold interdigitated transducers. Phosphatase and esterase activities were inhibited, respectively, by h...An original bi-enzymatic biosensor was designed by immobilizing Arthrospira platensis cells, called Spirulina, on gold interdigitated transducers. Phosphatase and esterase activities were inhibited, respectively, by heavy metals and by pesticides. Inhibition activities were observed with different mixtures of pesticides + heavy metals. The quantification limits for Cd2+ and Hg2+ are 10-20 M in mixture and in pure solution. The quantification limits of parathion-methyl, paraoxon-methyl and triazine are respectively 10-20 M, 10-18 M and 10-20 M in mixture and pure solutions. These results show that there is no synergistic effect between the two families of pollutants. Qualitative contamination of effluent samples and their purification after passing through a municipal wastewater treatment plant were observed by our bi-enzymatic biosensor and confirmed by classical analytical techniques for heavy metal ions.展开更多
Measurement of the electrical conductivity of electrolytes and heterogeneous materials containing them is accompanied by numerous physical and electrochemical processes, complicating measuring and interpretation of da...Measurement of the electrical conductivity of electrolytes and heterogeneous materials containing them is accompanied by numerous physical and electrochemical processes, complicating measuring and interpretation of data. As a result, the measurement of the electrical conductivity of such a system is a difficult and not finally resolved problem. The new method of resistance measurement of the electrolytic systems is substantiated and tested on example of heterogeneous electrolytic system “lignin-calcium chloride water solution” in this article. The method is based on measurement of resistance of the electrolytic system at different voltages (DC) on the cell and the consequent approximation of the acquired data taking into consideration volume charges and potential barriers arising on the boarders of electrodes and electrolytic materials. Extrapolation of the resistance to the limiting small current lets one obtain a characteristic value of the active resistance of the electrolytic system. The method is technically simple, inexpensive and has several advantages compared to the methods based on AC measurements.展开更多
文摘An original bi-enzymatic biosensor was designed by immobilizing Arthrospira platensis cells, called Spirulina, on gold interdigitated transducers. Phosphatase and esterase activities were inhibited, respectively, by heavy metals and by pesticides. Inhibition activities were observed with different mixtures of pesticides + heavy metals. The quantification limits for Cd2+ and Hg2+ are 10-20 M in mixture and in pure solution. The quantification limits of parathion-methyl, paraoxon-methyl and triazine are respectively 10-20 M, 10-18 M and 10-20 M in mixture and pure solutions. These results show that there is no synergistic effect between the two families of pollutants. Qualitative contamination of effluent samples and their purification after passing through a municipal wastewater treatment plant were observed by our bi-enzymatic biosensor and confirmed by classical analytical techniques for heavy metal ions.
文摘Measurement of the electrical conductivity of electrolytes and heterogeneous materials containing them is accompanied by numerous physical and electrochemical processes, complicating measuring and interpretation of data. As a result, the measurement of the electrical conductivity of such a system is a difficult and not finally resolved problem. The new method of resistance measurement of the electrolytic systems is substantiated and tested on example of heterogeneous electrolytic system “lignin-calcium chloride water solution” in this article. The method is based on measurement of resistance of the electrolytic system at different voltages (DC) on the cell and the consequent approximation of the acquired data taking into consideration volume charges and potential barriers arising on the boarders of electrodes and electrolytic materials. Extrapolation of the resistance to the limiting small current lets one obtain a characteristic value of the active resistance of the electrolytic system. The method is technically simple, inexpensive and has several advantages compared to the methods based on AC measurements.
