Abstract: The present invention discloses an apparatus for the determination of chemicals in a sample flow, which includes in combination a hollow conical chamber having large and small diameter portions. An entrance conduit communicates with the large diameter portion of the chamber to introduce a sample flow into the chamber in a generally tangential direction and the sample travels in a generally spirally extending path to the small diameter portion. A first axially extending conduit is connected to the small diameter portion to provide for the exit of a heavier fraction of the sample flow from the conical chamber. A second exit conduit is connected in an axial manner to the large diameter portion of the conical chamber to exit a lighter fraction of the sample flow from the conical chamber. First and second spaced electrodes are positioned in the first exit conduit.