The detector most used in HPLC of carbohydrates to date has been the differential refractometer, though the introduction of UV detectors capable of operating at 190 nm makes possible the application of this method to HPLC of sugars. 1 For monosaccharides, the sensitivity of this UV detector is approximately 12 times greater than that of most RI detectors (detection limit approximately 20 μg sugar 2 ), but for oligosaccharides sensitivity decreases with increasing DP of the sugar. Derivatization of sugars (benzoylation 3 or 4-nitrobenzoylation 4 ) permits the use of UV detectors operating at 260 nm; the resulting increase in sensitivity makes possible detection of carbohydrates in the nanogram range. 4