Reverse Injection Enthalpimetric Technique for the Determination of Cerium(IV) and Sulpha Drugs

Abstract

007, 71(1),141-148) has been subjected to further applications. In this work Ce(IV) has
been determined using Reverse Injection Enthalpimetry (RIE) , in which the analyte Ce(IV)
was added to excess reagent (sulphanilic acid). For the determination of (4 - 35 μg.mL-1)
Ce(IV) in the final solution, a fixed volume between (0.1 – 0.8)mL. analyte present in .
(0.5 M H2SO4), was injected into an excess of sulphanilic acid (20 ml. 1.25x10-2M) in the
thermometric cell. Only one blank of 0.5 ml.(0.5 M H2SO4) was performed and its value
was subtracted from all the results. The calibration curve was linear with R2 = 0.999 with a
recovery between 96 – 101% with precision of about 2%, and t-test showed no significant
difference between the true value and the mean at 95% confidence limit, indicating good
validity of the method. The above procedure was reversed for the determination of
sulphanilic acid and some sulpha drugs. In this case a portion of 0.5 mL. of the analyte or the
standard containing not less than 10mg of sulphanilic acid or the sulpha–drug is injected into
an excess of Ce(IV) as a reagent in the thermometric cell and the procedure will be
continued.