title: Determination of cinnamic acid in human urine by differential-pulse polarography.
abstract: The differential-pulse polarographic behaviour of cinnamic acid was studied in acetate and phosphate buffer solutions (pH 3.5-7.5). The reduction mechanism is discussed. The drug can be determined at pH 5.0 over the concentration range 5 x 10(-5)-1 x 10(-3) mol l-1. The effect of tetraalkylammonium salts on the electroanalytical determination of cinnamic acid was investigated. The direct determination of the drug (0.7-5.5 micrograms ml-1) in urine samples diluted with acetate buffer (pH 5.0) can be effected in the presence of 1 x 10(-3) mol l-1 cetyldimethylethylammonium bromide solution. The detection limit was found to be 0.1 microgram ml-1. The relative standard deviation from six determinations at the 5.5 micrograms ml-1 level was 1%.
authors.affiliation: Departamento de Química Analítica, Instituto de Química-Universidade Estadual Paulista, Araraquara-SP, Brazil.
authors.forename: V S
authors.initials: VS
authors.lastname: Ferreira
authors.forename: C B
authors.initials: CB
authors.lastname: Melios
authors.forename: M V
authors.initials: MV
authors.lastname: Zanoni
authors.forename: N R
authors.initials: NR
authors.lastname: Stradiotto
mesh_terms: D002934:Cinnamates / Q000652:urine*; D006801:Humans; D011048:Polarography
chemical_list: D002934:Cinnamates; C029010:cinnamic acid