Simultaneous determination of 8 kinds of organic acids in formula feed by capillary electrophoresis

An analytical method for organic acids (formic acid, fumaric acid, tartaric acid, malic acid, citric acid, acetic acid, lactic acid and propionic acid ) in formula feeds by capillary electrophoresis (CE) was established. Organ ic acids were simultaneously extracted with water. The extract was filtered , diluted with 0.02 mol/L NaOH, and deproteinized by an ultrafiltration fil ter (30 kDa cut-off). The recovery test was conducted with 3 kinds of formu la feed spiked with 8 kinds of organic acids at levels of 0.05 similar to 2 .0%. The mean recovery values were in the range of 85.1 similar to 107.3%, and the relative standard deviation of repeatability (RSD) was within 13.6% . A collaborative study (3 laboratories) was conducted with formula feed sp iked with 8 kinds of organic acids at levels of 0.1 similar to 1.0%. The me an recovery was 87.3 similar to 105.0%, and the relative standard deviation of reproducibility (RSDR) was within 16.3%.