title: Kinetic fluorimetric study of the oxidation reaction of folinic acid (leucovorin) with potassium permanganate. Determination in human urine.
abstract: In this study a kinetic fluorimetric method for the determination of folinic acid (leucovorin, LV) in human urine has been developed. The fluorescence emission generated by the oxidation reaction between LV and potassium permanganate in alkaline medium has been monitored at 360nm (excitation wavelength 290nm). The effect of instrumental and experimental variables on the reaction was investigated and a 0.17M sodium hydroxide, 3.3x10(-5)M KMnO(4) concentration and a temperature of 70 degrees C were selected for the reaction. The concentration range has been optimized between 10 and 700ngml(-1) of LV. The correlation coefficient was 0.9989. The sensitivity of the proposed method is 9.5ngml(-1) (expressed as limit of detection in accordance with the Clayton criterion). The determination time per sample is smaller than 200s. The proposed kinetic fluorimetric method has been applied to the direct determination of this compound in human urine. Recovery values from urine samples, containing LV, range from 82 to 110% (mean 96%).
authors.affiliation: Department of Analytical Chemistry, Faculty of Science, University of Extremadura, Avda Elvas s/n 06071 Badajoz, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Durán Merás
authors.forename: A
authors.initials: A
authors.lastname: Espinosa-Mansilla
authors.forename: M J
authors.initials: MJ
authors.lastname: Rodríguez Gómez
authors.forename: F
authors.initials: F
authors.lastname: Salinas López