“…Amino acids chromatographed in the presence of trichloroacetic acid (used in deproteinizing serum samples) show anomalous behavior, and this interference can be almost completely removed by predevelopment (two times) in ether saturated with formic acid (71). Besides the above-mentioned ion-exchange systems (69,72), sorbents with ion-exchange properties such as DEAE-cellulose have also been used as the stationary phase for TLC separation of amino acids. Besides the above-mentioned ion-exchange systems (69,72), sorbents with ion-exchange properties such as DEAE-cellulose have also been used as the stationary phase for TLC separation of amino acids.…”