A Caltech Library Service

A reliable algorithm for calculating stoichiometry parameters in the hard modeling of spectrophotometric titration data

Kazmierczak, Nathanael P. and Chew, Joyce A. and Vander Griend, Douglas A. (2022) A reliable algorithm for calculating stoichiometry parameters in the hard modeling of spectrophotometric titration data. Journal of Chemometrics, 36 (6). Art. No. e3409. ISSN 0886-9383. doi:10.1002/cem.3409.

[img] MS Word (Figures S1-S4; Tables S1-S5) - Supplemental Material
See Usage Policy.


Use this Persistent URL to link to this item:


Computation of binding constants from spectrophotometric titration data is a very popular application of chemometric hard modeling. However, the calculated values are misleading if the correct binding model is not used. Given that many supramolecular systems of interest feature unknown speciation, a priori determination of binding stoichiometry constitutes an important unsolved problem in chemometrics. We present a new and reliable algorithm for accomplishing this task, implemented using a hybrid particle swarm optimization technique. Simultaneous optimization of stoichiometry ratios and binding constants allows the optimal binding model to be calculated in just a few minutes for systems with up to four reactions. Simulated data studies demonstrate that the algorithm finds the correct stoichiometry with up to nine reactions in the absence of noise, including accurately determining species with unusual stoichiometry, such as H2G5. Application to four experimental datasets shows the algorithm is robust to experimental errors for a variety of chemical systems and binding models. This algorithm will facilitate the discovery of complex binding models, increase efficiency in titration analysis, and avert incorrect stoichiometry models, thereby improving the reliability of binding constant information in spectrophotometric titrations.

Item Type:Article
Related URLs:
URLURL TypeDescription Information ItemPeer Review History
Kazmierczak, Nathanael P.0000-0002-7822-6769
Chew, Joyce A.0000-0003-2144-1924
Vander Griend, Douglas A.0000-0002-8828-1112
Additional Information:© 2022 John Wiley & Sons Ltd. Issue Online: 18 June 2022; Version of Record online: 25 May 2022; Accepted manuscript online: 08 May 2022; Manuscript accepted: 04 May 2022; Manuscript revised: 29 April 2022; Manuscript received: 14 March 2022. Funding information: National Science Foundation Graduate Research Fellowship, Grant/Award Numbers: DGE-2034835, DGE-1745301; Hertz Fellowship; Arnold and Mabel Beckman Foundation; National Science Foundation, Grant/Award Numbers: 1726260, 2004005. Peer Review: The peer review history for this article is available at Data Availability Statement: The data that support the findings of this study are openly available at, doi:10.5281/zenodo.6345367.
Funding AgencyGrant Number
NSF Graduate Research FellowshipDGE-2034835
NSF Graduate Research FellowshipDGE-1745301
Fannie and John Hertz FoundationUNSPECIFIED
Arnold and Mabel Beckman FoundationUNSPECIFIED
Subject Keywords:binding constants; hard modeling; stoichiometry optimizationp; titration analysis
Issue or Number:6
Record Number:CaltechAUTHORS:20220708-277136700
Persistent URL:
Official Citation:Kazmierczak, NP, Chew, JA, Vander Griend, DA. A reliable algorithm for calculating stoichiometry parameters in the hard modeling of spectrophotometric titration data. Journal of Chemometrics. 2022; 36(6):e3409. doi:10.1002/cem.3409
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:115442
Deposited By: Tony Diaz
Deposited On:11 Jul 2022 18:08
Last Modified:11 Jul 2022 18:08

Repository Staff Only: item control page