title: A New Indirect Spectrofluorimetric Method for Determination of Ascorbic Acid with 2,4,6-Tripyridyl-S-Triazine in Pharmaceutical Samples.
abstract: Ascorbic acid (AA) is a water-soluble vitamin which shows no fluorescence. However, in reaction with iron(III), AA is oxidised to dehydroascorbic acid and iron(III) is reduced to iron(II) which forms a complex with 2,4,6-tripyridyl-S-triazine (TPTZ) in buffered medium. The relative fluorescence intensity of the resulting Fe(TPTZ)₂(2+) complex can be measured at excitation and emission wavelengths of 393 and 790 nm, respectively. Based on this data, a new indirect spectrofluorimetric method for the determination of AA in pharmaceutical samples was proposed. Influence of the reaction conditions, such as acidity of acetic buffer, concentration of TPTZ and iron(III), reaction time and instrumental parameters were investigated in detail. The linear range was from 5.4 × 10(-4) to 5.4 × 10(-6) mol·L(-1) (R = 0.9971). The LOD was 7.7 × 10(-7) mol·L(-1) and LOQ was 2.3 × 10(-4) mol·L(-1). Fourteen pharmaceutical samples containing various amounts of AA were analysed. Influences of potential interfering substances were also examined. Analysis of commercial pharmaceutical formulations showed good correlation with the nominal values given by the manufacturers and with the results obtained by a titration method. The proposed method can be applied in routine quality control in the pharmaceutical industry due to its sensitivity, simplicity, selectivity and low cost.
authors.affiliation: Department of Chemistry, Faculty of Science, University of Sarajevo, Zmaja od Bosne 33-35, Sarajevo 71 000, Bosnia and Herzegovina. klepolejla@gmail.com.
authors.forename: Lejla
authors.initials: L
authors.lastname: Klepo
authors.affiliation: Department of Chemistry, Faculty of Science, University of Sarajevo, Zmaja od Bosne 33-35, Sarajevo 71 000, Bosnia and Herzegovina. chopraamira@yahoo.com.
authors.forename: Amira
authors.initials: A
authors.lastname: Copra-Janicijevic
authors.affiliation: Faculty of Chemistry and Technology, University of Split, Teslina 10, Split 21 000, Croatia. kukoc@ktf-split.hr.
authors.forename: Lea
authors.initials: L
authors.lastname: Kukoc-Modun
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis* / Q000737:chemistry*; D005290:Ferric Compounds; D006863:Hydrogen-Ion Concentration; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013050:Spectrometry, Fluorescence / Q000379:methods*; D014227:Triazines / Q000032:analysis* / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; D014227:Triazines; D001205:Ascorbic Acid; C002849:2,4,6-tripyridyl-s-triazine
keywords: 2,4,6-tripyridyl-S-triazine; ascorbic acid; spectrofluorimetry