Toxicity assessment of cyanide and tetramethylene disulfotetramine (tetramine) using luminescent bacteria Vibrio-qinghaiensis and PbO₂ electrochemical sensor

The toxicities of cyanide and tetramethylene disulfotetramine (tetramine) were evaluated by two methods of luminescent bacteria and PbO₂ electrochemical sensor. Vibrio-qinghaiensis, a kind of luminescent bacteria, can produce biolurninescence and the bioluminescence was decreased with the addition of toxicants. The toxicities of cyanide and tetramine were expressed as 10 min-EC₅₀ value, which was the concentration of chemical that reduces the light output by 50% after contact for 10 min. Nano PbO₂ modified electrode, a rapid toxicity determination method was also described in this work. By the PbO₂ modified electrode, the current responses of Escherichia coli (E. coli) were changed with the addition of toxicants. The value of 10 min-EC50 was also provided with the PbO₂ electrochemical sensor. Compared with the 10 min-EC50 and detection limits (38.38 and 0.60 μg/mL for cyanide, 0.24 and 0.02 μg/mL for tetramine) with luminescent bacteria, the PbO₂ sensor provided a simple and convenient method with lower 10 min-EC50 and detection limits (26.37 and 0.52 μg/mL for cyanide, 0.21 and 0.01 μg/mL for tetramine) and fast response time.