Determination of low-molecular-mass heparin using affinity capillary electrophoresis

This work is dedicated to determination of low-molecular-mass heparin, namely Fraxiparine, using affinity capillary electrophoresis. Fraxiparine was detected indirectly by using tetraarginine, which forms a stable complex with Fraxiparine. The developed method used 50 mu m i.d. fused silica capillary (length was optimized). Phosphoric acid (9 mM) with addition of 0.1% w/v hydroxyethylcellulose was used as a background electrolyte. The samples were injected hydrodynamically into the capillary by a pressure of 5 kPa. After that, voltage was applied for a certain period of time. During this time the zones migrate through each other, which enables formation of the complex. Fraxiparine was determined from the amount of remaining free tetraarginine. The injection time of Fraxiparine was subject to optimization. After the optimization, different experiments were performed for the determination of Fraxiparine in blood plasma. Acetonitrile, acetone and trifluoroacetic acid were tested for deproteination of the samples.