[Determination of cytidine and adenosine in cordyceps by monolithiccapillary electrochromatography]

To develop a capillary electrochromatography method for determination of cytidine and adenosine in cordyceps with monolithic column.

The total length of the home-made ploy-butyl methacrylate (PBMA) monolithic capillary electrochromatographic column was 34.5 cm with the effective length of 26.0 cm. The mobile phase was 20 mmol x L(-1) borax solution (adjusted pH to 3.5 using acetic acid); the operation voltage was 15 kV; sample injection pressure was 6 bar x 0.1 min; column temperature was 30 degrees C and the detection wavelength was set at 214 nm. The internal standard solution was 100 mg x L(-1) trimethoprim solution [ethanol-mobile phase (1 : 1) was used as the solvent].

The results indicated that the concentrations of cytidine and adenosine within the range of 12.5-125 mg x L(-1) were linearly correlated with the relative peak areas, and the correlative coefficients (r) were 0.999 8 and 0.999 3, respectively. The LOD (S/N = 3) and LOQ (S/N = 10) of cytidine were 2.14 and 7.14 mg x L(-1), and those of adenosine were 1.88 and 6.25 mg x L(-1). The average recoveries of the two nucleosides were from 97.2% to 103.5% with relative standard deviation (RSD) within 0.9%-2.6% in three levels.

The method is effective and credible. It can be used to determine the contents of cytidine and adenosine in cordyceps.