Electrogenerated Chemiluminescence Derivatization Reagent, 3-Isobutyl-9,10-dimethoxy-1,3,4,6,7,11b- hexahydro-2H-pyrido[2,1-a]isoquinolin-2-ylamine, for Carboxylic Acid in High-Performance Liquid Chromatography Using Tris(2,2‘-bipyridine)ruthenium(II)

• Published in: Analytical chemistry (Washington) Vol. 75; no. 4; pp. 940 - 946
• Main Authors: Morita, Hirotoshi, Konishi, Masaharu
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.02.2003
• Subjects: 2,2'-Dipyridyl - analogs & derivatives; 2,2'-Dipyridyl - chemistry; Analytical chemistry; Carboxylic Acids - analysis; Chemistry; Chromatographic methods and physical methods associated with chromatography; Chromatography, High Pressure Liquid - methods; Coordination Complexes; Electrochemistry; Exact sciences and technology; Fatty Acids, Nonesterified - blood; General and physical chemistry; Humans; Indicators and Reagents; Luminescent Measurements; Other chromatographic methods; Photoelectrochemistry. Electrochemiluminescence; Reversed phase chromatography; Carboxylic acid; Detection limit; HPLC chromatography; Bipyridines; Electrochemiluminescence; Ruthenium II; Derivatization; Isocratic condition
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac020377i

3-Isobutyl-9,10-dimethoxy-1,3,4,6,7,11b-hexahydro-2H-pyrido[2,1-a]isoquinolin-2-ylamine (IDHPIA) was found to be a selective and highly sensitive derivatization reagent for carboxylic acid by high-performance liquid chromatography (HPLC) with electrogenerated chemiluminescence detection using tris(2,2‘-bipyridine)ruthenium(II). Free fatty acids and phenylbutylic acid were used as model compounds of carboxylic acids, and the derivatization conditions were optimized with myristic acid. Under the mild reaction conditions of room temperature for 45 min in acetonitrile containing 2-bromo-1-ethylpyridinium tetrafluoroborate and 9-methyl-3,4-dihydro-2H-pyrido[1,2-a]pyrimidin-2-one, all the fatty acids tested were reacted with IDHPIA to produce highly sensitive derivatives. The chemiluminescence intensity was essentially the same for all fatty acids. The derivatives obtained from 10 free fatty acids were completely separated by reversed-phase chromatography under isocratic elution conditions. The on-column detection limit (signal-to-noise ratio of 3) with proposed HPLC separation and chemiluminescence detection was 0.5 and 0.6 fmol for myristic acid and phenylbutylic acid, respectively. IDHPIA was 100-fold more sensitive than previously developed reagents (Morita, H.; Konishi, M. Anal. Chem. 2002, 74, 1584−1589). The free fatty acids in human serum were successfully determined using the present method.