Tomohiko Yoshida

6-Methoxy-2-methylsulfonylquinoline-4-carbonyl chloride as a fluorescence derivatization reagent for amines in liquid chromatography

6-Methoxy-2-methylsulfonylquinoline-4-carbonyl chloride was found to be a sensitive fluorescence derivatization reagent for primary amines. The reagent reacted with the amines in acetonitrile in the presence of potassium carbonate to give the corresponding fluorescent amides, which could be separated on a TSKgel ODS-80TM reversed-phase column with aqueous 55% v/v acetonitrile as eluent. Pentylamine, hexylamine, heptylamine and octylamine were used to investigate the derivatization conditions. The detection limits (signal-to-noise ratio = 3) of these amines were in the range 0.5–1.0 pmol per 20 µl injection volume. Alcohols did not give any fluorescent products under these derivatization conditions.

Fluorometric Determination of Some Primary Aromatic Amines with 4-Methoxy-m-phenylenediamine

A sensitive fluorometric method for the determination of primary aromatic amines is described. The procedure consists of diazotization of the amino group followed by coupling with 4-methoxy-m-phenylenediamine (MPD), and reaction of the resulting azo compound with ammoniacal cupric sulfate. By this reaction, primary aromatic amines are derivatized to intensely fluorescent compounds, and a method for the determination of p-aminobenzoic acid (PABA) was established. A linear relationship was observed between the PABA concentration and the fluorescence intensity in the range of 0.001-1.0 μg/ml. The proposed method is applicable to the determination of other primary aromatic amines.

2(1H)-quinolinethione derivatives as organic reagents. II. Properties of some 2(1H)-quinolinethione derivatives and application to the potentiometric titration of the silver ion.

Halogen derivatives of 2 (1H)-quinolinethione, alkyl derivatives of 1, 2-dihydro-2-thioxo-4-quinolinecarboxylic acid, and alkyl 1, 2-dihydro-2-thioxo-4-quinolinecarboxylate were synthesized. The detection limits for metal ions with these reagents were examined by spot tests. The metal ions which gave a precipitate with these reagents were the same as those reported previously. iso-Amyl 1, 2-dihydro-2-thioxo-4-quinolinecarboxylate (ATQ) forms a 1-to-1 compound with silver, and an ethanolic solution of ATQ was used as a titrant to determine 0.01-0.0001 M silver ions potentiometrically. The coefficient of variation was 1.8% (n=10) for 107.4 μg of silver. Silver protein was titrated potentiometrically with ATQ in 50% (v/v) ethanolic solution. The silver content was 8.0%, with a coefficient of variation of 1.8% (n=5).