0000000000594133
AUTHOR
M. Catalá-icardo
showing 2 related works from this author
Determination of Amino Acids by Micellar High-Performance Liquid Chromatography and Pre-column Derivatization withO-Phthalaldehyde and N-Acetyl-L-cys…
1995
Abstract Micellar liquid chromatography of proteic primary amino acids with pre-column derivatization with o-phthalaldehyde (OPA) and N-acetyl-L-cysteine was studied, using mobile phases containing a short-chain alcohol. The modification of pH gave a large variation of the retention as a result of the protonation of the carboxylate group of amino acids. Maximum resolution and adequate retentions were achieved with a 0.05 M sodium dodecyl sulphate/3% propanol mobile phase at pH 3. The reproducibility was lower than 1.0% at a 1 × 10−4 M concentration level and between 0.6 and 2.2% for 1 × 10−6 M. The determination of glycine, lysine, methionine and threonine in pharmaceutical formulations gav…
Correlation between hydrophobicity of amino acids and retention data in reversed-phase liquid chromatography with micellar eluents
1995
Hydrophobic character is usually expressed in terms of the partition coefficient in 1-octanol-water (log PO/W). However, measurement of this coefficient is often problematic. Retention in micellar liquid chromatography is mainly due to hydrophobic interactions and can also be used as an index of hydrophobicity. A hydrophobicity scale was established with retention data foro-phthalaldehyde (OPA)-N-acetyl-L-cysteine (NAC) amino acid derivatives, using the glycine derivative as reference. Since the OPA-NAC derivatives only differ in the nature of R1 in the amino acid (R1CH(COOH)NH2), in the absence of electrostatic interactions the hydrophobic character of the substituent was responsible for r…