Image:4-30 difference in derivative.png

The difference in the derivative between the control magnetic yoke and a cone magnet and two small cylinders flanking a flow cell. A positive value indicates that the derivative in the control is greater. The derivative is measured in Tesla per inch, and the length is measured in inches. Notice how much noise there is.

Between the left side of the graph and the red line is the area representing where liquid would be present in a flow cell. The area to the right of the black line represents where the liquid would be in one of the thin walled micro-centrifuge tubes.