Capillary electrophoresis (CE) is a well-established method for the separation of glycosaminioglycans (GAGs) such as heparin and dermatin sulfate (DS) as well as the potential adulterant over-sulfated chondroitin sulfate (OSCS). However, standard UV detection at 200 nm is not effective for the qualitative identification of heparin and OSCS. CE with indirect photometric detection (IPD) has been utilized for heparin hydrolysis products but not intact GAGs. We have reported previously that naphthalene mono-, di-, and tri-sulfonates can be effective indirect detection reagents for a wide range of inorganic anions, organic acids, and aliphatic anionic surfactants. In this work, CE with IPD using naphthalenedisulfonate (NDS) at 288 nm did visualize heparin and DS as the expected negative peaks but OSCS is seen as a positive peak. Using a run buffer of 850 mM Tris at pH 3 and 20 mM NDS with –30 kV applied to a 52 cm × 20 micron ID fused silica capillary, OSCS, heparin, and DS are separated in about 16 min. A comparison of NDS concentrations from 4 to 20 mM did not show a change in analyte migration times but did improve OSCS signal response. Linearity is shown from 1-10 mg/mL for OSCS, 12-50 mg/mL for heparin, and 12-90 mg/mL for DS. Limits of detection are about 2 mg/mL for OSCS and 10-12 mg/mL for heparin and DS. Detection sensitivity of these GAGs is still better at 200 nm but this indirect detection approach provides some qualitative information with respect to OSCS as compared to heparin. This could be particularly important when using a 50 micron capillary because baseline resolution of OSCS and heparin is more difficult.

Capillary electrophoresis of glycosaminoglycans with indirect detection using naphthalene sulfonates

255th National Meeting (2018)

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