High-performance capillary electrophoresis of hyaluronic acid: determination of its amount and molecular mass.

The amount and the molecular mass of hyaluronic acid (HA) were determined by high-performance capillary electrophoresis. HA was observed at around 15 min by using an untreated fused-silica capillary (75 microns I.D.) of 58 cm length (effective length, 50 cm) at 20 kV in 50 mM phosphate buffer (pH 4.0). Calibration curves showed good linearity from 0.01 mg/ml to 3.3 mg/ml for all HA samples examined. The lower limit of detection by monitoring the absorbance at 185 nm was 1.0 microgram/ml at the signal-to-noise ratio of 5. HA samples were examined in a buffer containing pullulan (PU) as an additive for the matrix formation material. The HA samples showed marked peak-broadening when analyzed in the buffer solution containing PU with a specified molecular mass. The peak broadening was based on the dispersion of the molecular mass of the HA sample analyzed.