title: Kinetic spectrophotometric method for the determination of oxalic acid by its catalytic effect on the oxidation of safranine by dichromate.
abstract: A new catalytic kinetic spectrophotometric method for the determination of oxalic acid has been described based on its catalytic effect on the redox reaction between safranine and dichromate in dilute sulfuric acid media. The reaction is monitored photometrically by measuring the decrease in absorbance of safranine at the maximum wavelength of 530 nm. Under the optimum conditions, a calibration graph from 0.10 to 10.00 microg ml(-1) of oxalic acid with a detection limit of 0.08 microg ml(-1) was obtained. The relative standard deviation (R.S.D.) for ten replicate measurements of 1.0 and 5.0 microg ml(-1) oxalic acid was 2.7 and 2.5%, respectively. The purposed method is simple, sensitive, selective and inexpensive. The applicability of the proposed method was determined by the determination of oxalic acid in spinach and wastewater samples with satisfactory results.
authors.affiliation: College of Chemistry, Isfahan University of Technology, Iran. ensafi@cc.iut.ac.ir
authors.forename: A A
authors.initials: AA
authors.lastname: Ensafi
authors.forename: S
authors.initials: S
authors.lastname: Abbasi
authors.forename: B
authors.initials: B
authors.lastname: Rezaei
mesh_terms: D002138:Calibration; D002384:Catalysis; D019815:Oxalic Acid / Q000032:analysis* / Q000737:chemistry; D010084:Oxidation-Reduction; D010619:Phenazines / Q000737:chemistry*; D011192:Potassium Dichromate / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013053:Spectrophotometry / Q000379:methods*; D018724:Spinacia oleracea / Q000737:chemistry; D013464:Sulfuric Acids / Q000737:chemistry; D013696:Temperature
chemical_list: D010619:Phenazines; D013464:Sulfuric Acids; D019815:Oxalic Acid; C033158:sulfuric acid; D011192:Potassium Dichromate; C009195:safranine T