Peer review

Amino acids derivatized with o-phthaldialdehyde were separated by high performance liquid chromatography on a reverse phase C8 column with a ternary gradient. Multilevel calibration permits the analytical quantitation within the range of 50 to 3500 pMol of the individual amino acids in one run. The reproducibility of the analysis in consecutive runs is ± 3%. HeLa cells grown in suspension cultures were harvested by either centrifugation in the cold or by centrifugation through dibutylphthalate. Amino acids were extracted with methanol-water. Cells not exposed to aqueous media prior to extraction show an up to 3 fold higher level of amino acids in the intracellular pool.

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