PSEUDO-DERIVATIVE CURVES FOR THE DETERMINATION OF TITRATION END POINTS

摘要

The derivative curve of the sigmoids produced during titrations with potentiometric monitoring offers an accurate way of determining the end points of titrations. This paper presents the generation of ''pseudo-first-derivative curves,'' where advantage is taken of the difference between the sigmoids resulting from two runs of a titrimetric determination due to random error. In situations where the difference between two sigmoids is practically indiscernible, a sigmoid from a titration with a deliberate change in the reaction medium to alter the activity of the analyte will allow the generation of the ''derivative curve'' from two runs. This technique also provides a convenient method for confirming the presence of a suspected analyte. Intentional additions of extremely small quantities of an analyte will allow qualitative analysis for the added analyte in mixtures of analytes amenable for analysis by potentiometry. (C) 1996 Academic Press, Inc. [References: 6]