A new analytical technique in capillary electrophoresis: studying the levels of nucleotides in human breastmilk

The effect of nucleotides in the newborn is a determinant in this first stage of life, and their correct level in breastmilk is vital. We have designed a new method for the assay of nucleotides in milk by capillary electrophoresis (CE) after acid hydrolysis. Breastmilk samples were collected from healthy mothers (ages, 25-35 years) of one month lactation, and stored at -20 °C. The duplicated samples were dissociated by acidic hydrolysis (HClO4) and the CE assay was performed in an uncoated fused-silica capillary using an alkaline (borate) electrophoretic separation system.The method gave good recoveries of 5'-mononucleotides. Under the conditions used, the actual CE analysis time was less than 20 minutes. The physiologically and nutritionally important nucleotides were detected at concentrations of 387 μg/100ml for UMP-5P, 385.3 μg/100ml for AMP-5P, 67 μg/100ml for CMP-5P, 172 μg/100ml for TMP-5P and 315 μg/100ml for GMP-5P. Nucleotides are a significant nutrient in infant growth, and capillary electrophoresis is a sensitive and efficient tool for the assay of nucleotides with a purine or pyrimidine base in breastmilk.