MINIATURIZED LIGHT-SCATTERING DETECTOR FOR PACKED CAPILLARY SUPERCRITICAL FLUID CHROMATOGRAPHY

Packed capillary columns provide excellent separation of neutral lipids by supercritical fluid chromatography. For these separations, it is necessary to add a polar modifier to the mobile phase; hitherto, a detector suitable for quantitative analysis has been lacking. For this purpose, a miniaturized evaporative light scattering detector for combination with packed microcolumns in supercritical fluid chromatography has been developed. Since the detector response is dependent on the mobile phase flow rate, a drop in response was found at flow rates above 16 mL min-1 of expanded mobile phase. However, below this flow rate, there was a region of relatively constant response. In this region, quantitative analysis could also be successfully performed when the pressure and/or the temperature of the separation were programmed. The detection limit was lower than 6 ng. With pressure programming, the relative standard deviation in peak area was less than 4%. Minor peaks gave higher RSD values. Further, it is demonstrated that argentation SFC of triacylglycerols provides separation according to chain length as well as to the degree of unsaturation.