Indirect Determination of Potassium Calcium and Magnesium in Blood Plasma by High Performance Capillary Electrophoresis with UV-Detection

Potassium sodium calcium and magnesium in blood plasma were separated by high performance capillary electrophoresis (HPCE) in a buffer medium of pH 5.5,using tartaric acid as complexing agent.Imidazole was used as background reagent in the UV-detection.Various conditions for the CE separation and UV-detection (including pH value of background buffer solution,concentration of imidazole solution and concentration of tartaric acid solution) were studied and optimized.The above mentioned cations were separated from each other satisfactorily within 4.5 min.Linear regression equations showing the relationships between the peak areas and concentrations of K+,Ca2+ and Mg2+ were given with values of correlation coefficients in the range of 0.998 4-0.999 4,and detection limits (S/N=3) of 0.20,0.12 and 0.06 mg·L-1 respectively.Values of RSD′s (n=6) for measurments of migration time and peak area were found to be less than 0.76% and 2.83% respectively.Overlapping of the absorption peak with the system peak made the determination of sodium ion impossible.Test for recovery was performed and values of recovery were found in the range from 95.34% to 104.29%.