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A modified system for thiazolinone conversion to thiohydantoin derivatives and their separation by high-pressure liquid chromatography

1985; Elsevier BV; Volume: 150; Issue: 2 Linguagem: Inglês

10.1016/0003-2697(85)90535-4

1096-0309

Ajit S. Bhown, John Bennett,

Chemical Synthesis and Analysis

An improved and very simple procedure for thiazolinone conversion to thiohydantoin derivatives and their separation by reverse-phase high-pressure liquid chromatography is described. Trifluoroacetic acid (10%) in ethyl acetate has been employed as a conversion reagent to circumvent the deamidation of acid amides and methylation of acidic amino acids, with a concomitant increase in the detection limits of these residues. Additionally, a very simple procedure has been developed for the separation of phenylthiohydantoin (PTH) derivatives of amino acids. The system takes advantage of the computer-controlled precise mixing of the solvents A and B to achieve accurate pH and thus avoid the necessity of pH adjustment of a buffer. The procedure is simple and highly reproducible, and separates all the 20 known PTH amino acids. The efficiency of the method has been examined on synthetic and natural proteins/peptides, in manual and autoconversion systems, over a period of more than 18 months.