Fluorescent labeling of drugs and simple organic compounds containing amine functional groups, utilizing dansyl chloride in Na(2)CO(3) buffer.
Fluorescent labeling of amine functional groups using dansyl chloride (DNS-Cl), and in sodium carbonate buffer, allowed the detection of 1 microg amounts of analytes. The methodology presented allows dansylation of primary, secondary, and tertiary amine groups at a temperature of 25 degrees C. The dansylation of tertiary amines involves a chemical reaction which removes one substituent (or branch) of the amine group. A one molar working concentration of Na(2)CO(3) is used, and is at pH 11.0. Compounds such as isopropylamine, dipropylamine, diethylamine, triethylamine, triisooctylamine, and N,N-dimethylaniline were labeled by use of DNS-Cl from samples obtained from a complex mixture of alkanes. The compound p-chloroaniline contains a primary amine group and is a solid at 25 degrees, quickly dissolves in the one molar sodium carbonate buffer and is dansylated in 15 min. Heroin, which contains a tertiary amine group, was extracted into ethyl acetate from an aqueous solution, then reacted with DNS-Cl. Benzocaine, a local anesthetic, was dansylated in 15 min. Tertiary amine groups incorporated in a rigid ring system, such as for caffeine, strychnine, and the ionic salt form of cocaine hydrochloride did not react with DNS-Cl under these conditions. The reaction time for tertiary amines was 2 h or less, and 15 min for compounds having primary and secondary amine groups. Separation of the dansylated compounds from unreacted DNS-Cl was accomplished by diethyl ether extraction of the aqueous reaction solution, followed by thin layer chromatography using various organic solvents such as acetone and methylene chloride.
Bartzatt
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Chemistry Department, College of Arts and Sciences, University of Nebraska, Omaha, NE 68182, USA. bartzatt@unomaha.edu
D000588:Amines / Q000737:chemistry*; D000814:Aniline Compounds / Q000737:chemistry; D001566:Benzocaine / Q000737:chemistry; D002021:Buffers; D002254:Carbonates / Q000737:chemistry; D002855:Chromatography, Thin Layer; D003619:Dansyl Compounds / Q000737:chemistry*; D005021:Ethylamines / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry; D003932:Heroin / Q000737:chemistry; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D011437:Propylamines / Q000737:chemistry
D000588:Amines; D000814:Aniline Compounds; D002021:Buffers; D002254:Carbonates; D003619:Dansyl Compounds; D005021:Ethylamines; D005456:Fluorescent Dyes; D004364:Pharmaceutical Preparations; D011437:Propylamines; C005686:sodium carbonate; D003932:Heroin; C015157:N,N-dimethylaniline; C038229:tri-N-octylamine; C029038:dansyl chloride; D001566:Benzocaine; C004658:4-chloroaniline