1. Application of data fitting in chemical equilibria studies
15th Iranian Workshop on Chemometrics
دانشگاه اصفهان
Application of data fitting in chemical equilibria studies
Gholamhassan Azimi
Faculty of Chemistry, University of Isfahan, Isfahan, IRAN

2. Definition A Short History Applications
15th Iranian Workshop on Chemometrics
Data Fitting In chemical …..
Definition A Short History Applications

3. Y=f(x,parametrs), Data Fitting:
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Data Fitting:
The process of fitting models to data and analyzing the accuracy of the fit.
Y=f(x,parametrs),
Chemistry based analysis of the data
(The Chemical model is known)
Chemical system(model): Component, species, species relations

4. Chemistry based analysis of data (The Chemical model is fully known)
15th Iranian Workshop on Chemometrics
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Chemistry based analysis of data
(The Chemical model is fully known)
Chemical system(model): Components, species, species relations
Data
(No. of data more than the No. of parameter, dependent and independent variables, e.g. Absorbance and pH….)
Model
A chemical model that describe the relation between species concentration and independent variable (spectrophotometric pH-metric titration, C=f(pH) , The model parameters are Stability constants generally)
A secondary model that relate the independent and real measured dependent variables
e.g. Abs=f(C), model parameters are sth such epsilon, pure chemical shift etc. )
Fitting
Considering the R2adjusted
Plotting normal probability plot for residuals; Visualizing residual plot
SSlack of fit must be non-significant

5. CX = [X] + xyz [X]x[Y]y[Z]z CY = [X] + xyz [X]x[Y]y[Z]z
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The law of mass action:
CX = [X] + xyz [X]x[Y]y[Z]z
CY = [X] + xyz [X]x[Y]y[Z]z
CZ = [Z] + xyz [X]x[Y]y[Z]z
X, Y, Z are called components
All XxYyZz are called species (components X, Y, Z are also species)

6. Generalised equations:
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Generalised equations:
Allow very compact MATLAB code:
c_spec =beta.*prod(repmat(c',1,nspec).^Model,1); %species conc
c_tot_calc=sum(Model.*repmat(c_spec,ncomp,1),2)'; %comp ctot calc

7. The function to minimise is:
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The function to minimise is:
The difference between the known total concentrations and the calculated values:

8. Algorithm of fitting 15th Iranian Workshop on Chemometrics
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Algorithm of fitting

9. SQUAD( about 42 years ago)
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SQUAD( about 42 years ago)

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11. HypSpec2014 15th Iranian Workshop on Chemometrics
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HypSpec2014
Equilibrium Constants from Spectrophotometric Data

12. The history of data fitting in Iran
15th Iranian Workshop on Chemometrics
The history of data fitting in Iran
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KINFIT: Codes in Fortran by Dr. Amini (~1990)

13. KINFIT: Codes in Basic by Dr. Ghasemi (~1993)
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KINFIT: Codes in Basic by Dr. Ghasemi (~1993)

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SQUAD and MINIQUAD: Codes in Fortran by Dr. Ghasemi and Dr. Vosough (~1996)

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New acyclic 1,2,4-triazole-based Schiff base hydrazone: Synthesis, characterization, spectrophotometric and computational studies
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 105 (2013) 338–343

18. H4L+Cu2+ 15th Iranian Workshop on Chemometrics
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H4L+Cu2+

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Synthesis, characterization and separation of chiral and achiral diastereomers of Schiff base Pd(II) complex: A comparative study of their DNA- and HSA-binding
+ Fish sperm DNA (FS-DNA)/EtBr
Journal of Photochemistry & Photobiology, B: Biology 163 (2016) 246–260

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Raman spectroscopic determination of the acidity constants of salicylaldoxime in aqueous solution
J. Raman Spectrosc. 2011,42, 505–511

21. In situ monitoring of pH titration by Raman spectroscopy
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In situ monitoring of pH titration by Raman spectroscopy
Spectrochimica Acta Part A 75 (2010) 1403–1410

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Analysis of non-isothermal chemical equilibria measurements; Determination of thermodynamic parameters of complexation equilibria (By Akbar Fattahi)

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Initial Estimate
Error
Calculated
Real Value
Parameter
Species
5000 75
15002-
15000- HΔ ML
100
0.4
39.9 40 SΔ
120
59915-
60000-
ML2
170
0.5
30.0-
30-
164
ML3
250
80.4-
80- 99
ML4
330
0.3
140-

24. Mole ratio titration at 25°C
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Non isothermal mole Ratio titration of Phenanthroline with Fe(II) ion
(By Akbar Fattahi)
Log β (T=25°C)
Error
calculated
Initial Estimates
Parameter
Complex
17.15 ± 0.07
291
5000-
H0Δ
[Fe(phen)3]2+ 1
82-
250
S0Δ
17.07± 0.10
Mole ratio titration at 25°C

25. Microscopic protonation constants of benzene tri-carboxcylic acids.
15th Iranian Workshop on Chemometrics
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Microscopic protonation constants of benzene tri-carboxcylic acids.
(Marzieh Azadi)

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29. 𝛿 𝑜𝑏𝑠 = 𝛿 𝐴 𝑋 𝐴 + 𝛿 𝐵 𝑋 𝐵 +𝛿 𝐶 𝑋 𝐶 +…
15th Iranian Workshop on Chemometrics
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𝛿 𝑜𝑏𝑠 = 𝛿 𝐴 𝑋 𝐴 + 𝛿 𝐵 𝑋 𝐵 +𝛿 𝐶 𝑋 𝐶 +…
𝑟= δ 𝑚𝑒𝑎𝑠 𝑜𝑏𝑠 − δ 𝑐𝑎𝑙𝑐 𝑜𝑏𝑠 = δ 𝑚𝑒𝑎𝑠 𝑜𝑏𝑠 −f(𝑝𝑎𝑟𝑎𝑚𝑒𝑡𝑒𝑟𝑠, 𝑚𝑜𝑑𝑒𝑙)
𝑪 = 𝑓 (𝑚𝑜𝑑𝑒𝑙, 𝒑)
𝜹 𝑐𝑎𝑙𝑐 𝑜𝑏𝑠 =𝑪𝒂=𝑪 𝐶 + 𝜹 𝑚𝑒𝑎𝑠 𝑜𝑏𝑠

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𝐷=1+ 𝐾 1 𝐻 + + 𝐾 1 𝐾 2 𝐻 𝐾 1 𝐾 2 𝐾 3 𝐻 + 3

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39. The Jacobian J 15th Iranian Workshop on Chemometrics
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The Jacobian J

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42. SS total=SS reg +SS res
SS res=SSerror+SS lack of fit
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