In situ DETERMINATION OF FLUORIDE IN GROUNDWATER USING N-OCTYL ACETAMIDE WITH IRON(III)-THIOCYANATE COMPLEX

摘要

This paper describes the nanodrop spectrophotometric determination of fluoride (F~-) in a ground water sample using the organic reagent N-octylacetamide (N-OAA) with iron(III)-thiocyanate complex. The iron(III)-thiocyanate complex was extracted with a chloroform solution of amide (N-phenylacetamide, N-alkylacetamide, alkyl = butyl, phenyl, hexyl, and octyl group). This method is based upon the bleaching effect of fluoride on the red-colored extracted complex of iron(III)-thiocyanate-OAA in chloroform. The absorbance of the extract was measured pre and post F~- addition at λ_(max) = 470 nm against the reagent blank. The limit of detection and %RSD of F~- was 38 μg/L and ±1.6%. The designed work followed Beer's law between 0.5 to 10 μg/mL with slope, intercept, and correlation coefficient values of -0.1101, 1.116, and -0.997, respectively. Furthermore, the applicability of the present investigation was extended for the determination of F~- in a groundwater sample, and the results obtained were compared with those from another reported method.