Capillary electrophoretic determination of inorganic ions in a prenatal vitamin formulation

Methods for the quantitative analysis of three cations (calcium, iron and zinc), and the qualitative analysis of several anionic species (chloride, sulfate, nitrate, citrate, fumerate, phosphate, carbonate and acetate) from a prenatal vitamin formulation by two different capillary ion electrophoresis methods are reported. The cation method was evaluated for detection and quantitation limits, precision, accuracy and linearity. For standard solutions, detection limits into the ng/ml range, and reproducibility that averaged less than 1% for migration time and 2% for area response were generated. Calibration plots exhibited linearity in excess of three orders of magnitude. In addition, excellent agreement between capillary ion electrophoresis and flame photometry quantitative results for the cation analyses were obtained.