On the confidence interval of the equivalence point in linear titrations.
As the point of intersection in linear-branch titration curves results from two optimized linear regressions, calculated by least-squares from n(1) and n(2) pairs of values of the signal y as a function of the added volume of titrant upsilon, the value of the equivalence volume V(e) has the character of an estimated average V (e) hence a confidence interval is associated with it. If the point of intersection V (e) belongs concomitantly to both regressions then the same value of y (e) should correspond to the two extreme values V'(e) and V'(e) of the confidence interval as to V (e) itself. Consequently, the two segments of the confidence interval are obtained by averaging each of the two unequal segments of the separate confidence intervals. Alternatively, considering that multiple estimates of V (e) can be obtained, the confidence interval can be calculated from the normally distributed random variables Deltaa' and Deltab' of the two linear regressions.
Liteanu
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Department of Chemical Technology, University of Cluj-Napoca, Cluj-Napoca, Romania.
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Liteanu
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