text: The determination of viscosity is based on Poiseuille's law:
  where t is the time it takes for a volume V to elute. The ratio  depends on R as the capillary radius, on the average applied pressure P, on its length L and on the dynamic viscosity η.
  The average pressure head is given by:
  with ρ the density of the liquid, g the Standard gravity and H the average head of the liquid.  In this way the viscosity of a fluid can be determined.
  Usually the viscosity of a liquid is compared to a liquid with an analyte for example a polymer dissolved in it. The relative viscosity is given by:
  where t and ρ are the elution time and density of the pure liquid. When the solution is very diluted 
  the so-called specific viscosity becomes:
  This specific viscosity is related to the concentration of the analyte through the Intrinsic viscosity [η] by the power series:
  or 
  where  is called the viscosity number.
  The intrinsic viscosity can be determined experimentally by measuring the viscosity number as function of concentration as the Y-axis intercept.