LOW-FLOW RATE MODIFIER ADDITION IN PACKED CAPILLARY COLUMN SUPERCRITICAL-FLUID CHROMATOGRAPHY

A new method to accurately deliver small amounts (0.5 to 20 mol%) of m odifier into CO2 mas used to study the effects of three different modi fiers (methanol, water, and formic acid) in packed capillary column SF C, The method allows the use of different modifiers, with minimal inst rument modification. The effects of the different modifiers at differe nt concentrations on retention and peak shape are shown by analyzing a polarity test mixture and a sample of free fatty acids.