Abstract
This paper describes the development of an automated Flow Injection analyzer for water toxicity assessment. The analyzer is validated by assessing the toxicity of heavy metal (Pb2+, Hg2+ and Cu2+) solutions. One hundred μL of a Vibrio fischeri suspension are injected in a carrier solution containing different heavy metal concentrations. Biosensor cells are mixed with the toxic carrier solution in the mixing coil on the way to the detector. Response registered is % inhibition of biosensor bioluminescence due to heavy metal toxicity in comparison to that resulting by injecting the Vibrio fischeri suspension in deionised water. Carrier solutions of mercury showed higher toxicity than the other heavy metals, whereas all metals show concentration related levels of toxicity. The biosensor’s response to carrier solutions of different pHs was tested. Vibrio fischeri’s bioluminescence is promoted in the pH 5–10 range. Experiments indicate that the whole cell biosensor, as applied in the automated fluidic system, responds to various toxic solutions.
Highlights
Current legislation in the EU (European Groundwater Directive) requires that water quality and the degree of contamination be assessed using chemical methods
The function and use of the developed system are assessed through the luminol peroxidase system and the response to toxic heavy metals using V. fischeri bacteria
It should be noted that V. fischeri culture cannot be used the way reagents are used: upon standing, due to gravity, bacteria tend to accumulate in the bottom of the container
Summary
Current legislation in the EU (European Groundwater Directive) requires that water quality and the degree of contamination be assessed using chemical methods. The development of whole-cell biosensors has seen increasing interest due to the capability of whole cells to convert complex substrates using specific metabolic pathways [6] and because of potential applications of whole-cell biosensors for monitoring of typical sum parameters. Such parameters, such as toxicity [7], biological oxygen demand [8] xenobiotic compounds [9] or heavy metals [10] cannot be monitored using enzyme-based sensors. The function and use of the developed system are assessed through the luminol peroxidase system and the response to toxic heavy metals using V. fischeri bacteria
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