Then the culture was centrifuged and resuspended in artificial sea water, preserving Imatinib Mesylate price their function but stopping their growth. This suspension was used with the FI system.2.2. ChemicalsAll Inhibitors,Modulators,Libraries chemicals used in the system were of analytical reagent grade purchased from Merck (Darmstadt, Germany). 0.0200 M Hg2+, Cu2+ and Pb2+ stock solutions were prepared by dissolving HgCl2, Cu(SO4)?5H2O, Pb(NO3)2?H2O. Acetate and phosphate buffer solutions were prepared for the pH ranges 3�C6 and 7�C11, respectively. pH was adjusted with NaOH and HCl.3.?Results and Discussion3.1. Detector Unit DevelopmentLight detection device: Photomultipliers (PMTs) are the most sensitive devices for the detection of low level optical signals.
An integrated Inhibitors,Modulators,Libraries PMT tube, incorporating the high voltage source and divider circuit along with an RS 232 signal output was selected (Hamamatsu HC-135 01) resulting in a compact biosensor device.Flow cell: Due to the use of a PMT detector, a wall-jet flow cell configuration was implemented. Figure 1 depicts the design of the prototype based on a previous study by Divritsioti et al. . The assembly was clamped between two stainless steel plates featuring appropriate openings for light detection and passage of the In (entrance of carrier solution) and W (exit of carrier solution Inhibitors,Modulators,Libraries to the wastes) polytrafluoroethylene (PTFE) tubes of 0.8 mm internal diameter.Figure 1.Flow cell design. In: carrier solution feed; W: waste; P: Plexiglas plate with immobilized cells; G: Gasket, 2mm thickness, 0.8cm2 area; Win: optical window from Plexiglas or Quartz (PMT detector is opposite).
Dimensions after assembly: 2 cm �� …Temperature control of the flow cell: To maintain immobilized bacteria at their optimal temperature, the flow cell is enclosed in a thermostated aluminium frame using a water bath at 20 ��C.3.2. Flow Injection Analyzer Development and OptimisationThe single line Flow Injection system that was developed, Inhibitors,Modulators,Libraries incorporating the above described detector unit, is depicted in Figure 3.Figure 3.Automated Flow Injection Analyzer. D: detector unit; IV: injection valve; L: mixing coil; W: waste; a: digital control signals; and b: data acquisition line.The analyzer design is based on the continuous flow of a carrier solution. The AV-951 sample loop of the injection valve is loaded with the Vibrio fischeri cell suspension that is subsequently automatically injected in the carrier solution flow.
Vibrio fischeri cells are mixed with the carrier solution in the mixing coil and then driven to the detector unit for bioluminescence assessment. % Inhibition of bioluminescence is assessed with selleck chemicals a two step experimental protocol. The first step is the assessment of V. fischeri bioluminescence by injection in a non toxic carrier solution. The second step is the assessment of V. fischeri bioluminescence by injection in a toxic carrier solution (sample).