title: Catalytic kinetic spectrophotometry for the determination of trace amount of oxalic acid in biological samples with oxalic acid-rhodamine B-potassium dichromate system.
abstract: A new catalytic kinetic spectrophotometric method was proposed for determining trace oxalic acid based on the catalytic effect of oxalate on the oxidation of potassium dichromate with rhodamin B in 0.10 M of sulfuric acid. Good linearity is obtained over the concentration range 0.40-6.0 microg/mL of oxalic acid. After the reactions of the catalytic and non-catalytic systems were terminated by using 2.00 mL of 4 M sodium hydroxide solution, they can be stable for 3 h at room temperature. The apparent activation energy of the catalytic reaction is 12.44 kJ/mol. The effect of 50 coexisting substances was observed. The method was used to determine trace oxalic acid in tea, spinach and urine samples with satisfactory results.
authors.affiliation: Research Center for Nanotechnology, Changchun University of Science and Technology, Weixing Road, Changchun 130022, China. zhaiqingzhou@sohu.com
authors.forename: Qing-Zhou
authors.initials: QZ
authors.lastname: Zhai
authors.forename: Xiao-Xia
authors.initials: XX
authors.lastname: Zhang
authors.forename: Qing-Zhou
authors.initials: QZ
authors.lastname: Liu
mesh_terms: D002384:Catalysis; D007202:Indicators and Reagents; D007700:Kinetics; D019815:Oxalic Acid / Q000032:analysis* / Q000652:urine; D011192:Potassium Dichromate / Q000737:chemistry*; D012235:Rhodamines / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013053:Spectrophotometry / Q000379:methods*; D018724:Spinacia oleracea / Q000737:chemistry; D013464:Sulfuric Acids / Q000737:chemistry; D013662:Tea / Q000737:chemistry; D013696:Temperature
chemical_list: D007202:Indicators and Reagents; D012235:Rhodamines; D013464:Sulfuric Acids; D013662:Tea; D019815:Oxalic Acid; C029773:rhodamine B; C033158:sulfuric acid; D011192:Potassium Dichromate