This freeware offers comprehensive pH and equilibrium calculations, real data analysis, and titration curve simulation for various solutions. With features including interpolation, smoothing, and nonlinear regression, it is capable of handling everything from simple to complicated mixtures.
One of the features of CurTiPot is pH calculation of any aqueous solution of strong and weak acids, bases, salts, buffers, and mixtures of up to 7 polyprotic systems (>40 species). It also estimates buffer capacity and activity coefficient. Another feature is the simulation and overlay of any acid-base titration, with or without pH and/or volume random errors. This feature is especially useful for titration with visual endpoint detection of "unknown" samples for learning, practicing, and evaluating the feasibility and accuracy of new titrations.
CurTiPot also offers an analysis of pH vs. volume data from simulated and real potentiometric titration curves by two methods. The first method involves graphical representation of curves, assisted by cubic splines interpolation and smoothing of derivative curves, for accurate evaluation of inflections (end-points). The second method involves determination of concentrations and refinement of pKa values by multiple nonlinear regression (based on the Solver supplement of Excel), which is essential for difficult titrations with undefined inflections, such as acid rain.
Another feature of CurTiPot is the generation of acid-base species distribution diagrams and curves of buffer capacity, protonation level, and average charge as a function of pH and added volume of titrant, with isoelectric point detection. The software also has an expandable database with pKa values of 250 acids and bases.
CurTiPot is incredibly easy to use. Simply unzip the curtipot_.xlsm file, open it with Microsoft Excel, enable macros and start learning, working, and teaching. No install/uninstall required, all macros are removed by closing the file. Furthermore, CurTiPot is completely free for educational and non-commercial not-for-profit use.
Version 4.1: Colors of visual indicators in the new virtual Titration module can now be loaded directly from the Database
Version 3.5.4: New alerts for cases of pH calculation with impaired accuracy ; Mean (average) charge calculations and curves vs. pH with detection of isoelectric point (pI or IEP).
Version 3.5.3: Mean (average) charge curves with detection of isoelectric point, pI, added to the Distribution module; mean charge of equilibrium species included in the pH_calc module
Version 3.5.2: Redesigned pH_calc module with explicit buffer capacity calculation; buffer capacity curves added to Distribution module; instructions updated
Version 3.4.1: Regression data analysis including activity calculation; Vista / Excel 2007 compatible; quick pKa loading from database
Version 3.3.1: Compatibility with Excel 2007/Windows Vista; direct loading of pKas from the acid-base Database at the modules pH calc., Virtual Titrator and Regression; new logarithmic distribution diagram overlayed on titration curve
Version 3.1: Enhanced Excel spreadsheet version (in English, with macros) of the executable version for MS- DOS, available since 1992 (in Portuguese)