Rapid and sensitive determination of Dns-amino acids in plasma using high-speed octadecyl liquid chromatographic columns

Rapid and sensitive methods are described for the separation of Dns-derivatives of twenty common amino acids using high-speed liquid chromatographic columns with 5-micron or 3-micron C18 packings. With the 5-micron column, the separation was completed in 37 min and with the 3-micron column in less than 20 min. The fluorimetric detection sensitivity of individual amino acids varied between 5 and 0.5 pmol. Plasma-free amino acids in mink were determined with the 5-micron column with a mean recovery of 101% for different amino acids. The mean coefficient of variation for ten subsequently analysed plasma samples was 4.8%.