Gas-liquid chromatographic measurement of guanidino acids.
We present a method for separating and measuring guanidino acids by gas-liquid chromatography. Compared to ion-exchange techniques, this system is faster, more sensitive, requires smaller sample volumes, is independent of colorimetric reactions, and permits simultaneous determination of both amino and guanidino acids. N-Trifluoracetyl-n-butyl esters are formed and then are separated by using a column containing a mixed silicone liquid phase coated on Chromosorb W-HP. Analytical recoveries from plasma ranged from 86 to 112% and were done without prior protein precipitation. Speculations as to the cause of this interference by protein include coprecipitation, protein-binding, and cyclization of the guanidines in the acids used for denaturation. Evidence presented suggests that all three occur: ultrafiltrability is diminished in the presence of protein and nuclear magnetic resonance demonstrates cyclization of some of these esters.
D000596:Amino Acids / Q000097:blood*; D001798:Blood Proteins; D011232:Chemical Precipitation; D002849:Chromatography, Gas / Q000379:methods*; D003500:Cyclization; D004952:Esters; D006146:Guanidines / Q000097:blood*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D011485:Protein Binding; D013386:Succinates; D014462:Ultrafiltration / Q000379:methods
D000596:Amino Acids; D001798:Blood Proteins; D004952:Esters; D006146:Guanidines; D013386:Succinates