Solid phase extraction cleans up wines reproducibly and reliably, facilitating analysis of underivatized amino acids in wines. Mass detection enables the quantification of co-eluting amino acids, in comparison with method involving derivatization and UV or FL detection.
Development of a sensitive and reproducible method for analysis of 22 underivatized amino acids and application of the method to quantify 17 amino acids in wine. Accurate quantification of proline, using an isotopically labeled internal standard.
In this Application Update, we combine into a single method individual improvements made to the standard AAA-Direct gradient program. These individual improvements are now in the AAA-Direct manual. This update shows that such combined changes to the AAA-Direct method improve the performance of our previously published method. This new method successfully determines amino acids in yeast extract-peptone-dextrose yeast culture medium (YPD Broth), and Dulbecco’s modified Eagle’s (with F-12), M199, L-15 (Leibovitz), and McCoy’s 5A media for mammalian cell culture.
In this technical note, we describe a procedure to screen sample matrices for their effect on peak area, peak height, and retention time. We demonstrate this procedure by testing ethanol for possible interferences in AAA-Direct. However, the method described here can also be used to evaluate any matrix component analyzed by chromatography with electrochemical detection. In this technical note, we use the term test sample (TS) to describe the specific test compound evaluated for possible interferences.
Amino acids present in protein formulations serve as buffers, bulking agents, stabilizers, and antioxidants. Eight specific amino acids are commonly used as excipients in protein therapeutic formulations due to their physicochemical properties. These include Arginine, Aspartic acid, Glutamic acid, Lysine, Proline, Glycine, Histidine, and Methionine. The UHPLC column, an Acclaim PA2 column, provides excellent separation characteristics for these un-labeled amino acids. Gradient conditions are adjusted by selecting appropriate ion-pairing reagents, pH and level of organic solvents.
