Identification and quantitation of human amniotic fluid components using capillary zone electrophoresis

A capillary electrophoresis method was used to measure albumin, immunoglobulin G (IgG), transferrin, and uric acid in 230 amniotic fluid (AF) samples collected at 15.15 ± 0.06 weeks gestation. Species were quantified by external calibration using thiamine as internal standard. All major components were detected within 10 min. Migration time reproducibility was 3.0% relative standard deviation (RSD) and normalized peak areas were 12% RSD or better at 190 nm from 81 measurements of a pooled AF sample. The separation profile was not affected by 10 h of storage at room temperature or by 10 freeze–thaw cycles, suggesting that frozen AF samples are suitable for protein biomarker studies.