Calculation of equilibrium constants from multiwavelength spectroscopic data—IIIModel-free analysis of spectrophotometric and ESR titrations

Gampp, Harald; Maeder, Marcel; Meyer, Charles J.; Zuberbühler, Andreas D.

doi:10.1016/0039-9140(85)80238-1

Cited by 475 publications

(257 citation statements)

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“…Computations relating to the determination of dissociation constants were performed by regression analysis of the UV/VIS spectra using the SPECFIT/32 [12][13][14][15][16] programmes. Most of graphs were plotted using ORIGIN 7.5 [49] and S-Plus [50].…”

Section: Computationsmentioning

confidence: 99%

“…However, a hard-modelling analysis cannot be applied if crucial information is missing. Softmodelling or model-free approaches, for example SPECFIT [12][13][14][15][16], are based on much more general prerequisites, such as positive molar absorbance, positive concentration of all species, unimodality of concentration profiles, and closure, that is, a concentration of all species is the same for all solutions. Naturally, if the strengths of hard-modelling and soft-modelling methodologies are combined, a much more powerful method of data analysis can be expected.…”

Section: Introductionmentioning

confidence: 99%

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The Thermodynamic Dissociation Constants of Clotrimazole, Terbinafine HCL, Acetylsalicylic Acid, Salicylic Acid, and Galanthamine by the Nonlinear Regression of Multiwavelength Spectrophotometric pH-Titration Data

2010

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The mixed dissociation constants of five drugs-clotrimazole, terbinafine HCl, acetylsalicylic acid, salicylic acid, and galanthamineat various ionic strengths I and at temperatures of 25 • C and 37 • C were determined with the use of multiwavelength and multivariate treatments of spectral data SPECFIT/32 nonlinear regression analysis and INDICES factor analysis. The factor analysis in the INDICES program predicts the number of components, when the data quality is high and the instrumental error is known. The thermodynamic dissociation constant pK T a was estimated by nonlinear regression of {pK a, I} data at 25 • C and 37 • C: for clotrimazole pK T a,1 = 4.38(1) and 4.16(3); for terbinafine HCl pK T a,1 = 4.19(3) and 4.12(5); for acetylsalicylic acid pK T a,1 = 3.49(25) and 3.41(15); for salicylic acid pK T a,1 = 3.01(1) and 3.00(1) and for galanthamine pK T a,1 = 8.21(1) and 7.99(2) where in brackets the standard deviation is in the last significant digits. Goodness-of-fit tests for various regression diagnostics enabled the reliability of the parameter estimates found to be proven. Pharma Algorithms predicts pK a being based on the structural formulae of drug compounds.

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Section: Computationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Thermodynamic Dissociation Constants of Clotrimazole, Terbinafine HCL, Acetylsalicylic Acid, Salicylic Acid, and Galanthamine by the Nonlinear Regression of Multiwavelength Spectrophotometric pH-Titration Data

2010

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“…The essential details of the software and the involved non-linear algorithms are given in literatures. [14][15][16][17] …”

Section: Apparatusmentioning

confidence: 99%

Spectrophotometric Titration of Cobalt(II) with CaCl2 in Mixed Solvents of 2-Propanol and Water for the Analysis of the Extraction Mechanism of Cobalt(II) by Salting-out in the Presence of CaCl2

Chung

Tabata

2005

ANAL. SCI.

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“…Eckschlager and Stepanek [2][3][4][5] pioneered the adaption and application of information theory in analytical chemistry. One of their important results gives the information gain of a quantitative determination [5] I toII )= n(X 2 -xl) \/nA I (q 1p)=lIn SV2xR-en (I) where q and p are the prior and posterior distribution of the analyte concentration for the specific cases of a rectangular prior distribution in (x,,x 2 ) and a Gaussian posterior with a standard deviation s determined from /A independent results.…”

Section: Information Theorymentioning

confidence: 99%

“…Acta 173, 253 (1985). [4] Gampp, H., Macder, M., Meyer, C. J., and Zuberbuhler, A.D., Talanta 32, 1133Talanta 32, (1985.[5] Malinowski, F. R., J. Chemometrics 1, 33 (1987).[6] Wold, S., Technometrics 20, 397 (1978). …”

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confidence: 99%

Chemometrics in Europe - Selected results

Wegscheider¹

1988

J. RES. NATL. BUR. STAN.

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to recalculate the concentration profiles. This process (truncation, normalization and pseudoinverse followed by pseudoinverse) was repeated until no further refinement occurred.The concentration profiles and spectra of the three unknown components of stearyl alcohol in carbon tetrachloride obtained in this manner were found to make chemical sense.This EFA procedure, unlike others, was successful in extracting concentration profiles from situations where one component profile was completely encompassed underneath another component profile.References [I] Malinowski, E. R., and Howery, D. G., Factor Analysis in Chemistry, Wiley Interscience, New York (1980). [2] Gemperline, P. G., J. Chem. Inf. Comput. Sci. 24, 206 (1984).[3] Vandeginste, B. G. M., Derks, W., and Kateman, G., Anal.Chim. Acta 173, 253 (1985). [4] Gampp, H., Macder, M., Meyer, C. J., and Zuberbuhler, A.D., Talanta 32, 1133Talanta 32, (1985.[5] Malinowski, F. R., J. Chemometrics 1, 33 (1987).[6] Wold, S., Technometrics 20, 397 (1978). Chemometrics in Europe:Selected Results Wolfhard WegscheiderInstitute for Analytical Chemistry Mikro-and Radiochemistry Technical University Graz, A-8010 Graz, AustriaChemometrics is a very international branch of science, perhaps more so than chemistry at large, and it is therefore appropriate to question the suitability of the topic to be presented. It is, however, the author's opinion that the profile of European chemometric research has a couple of distinct features that may originate more in the structure of the educational system than in the actual research topics. The profile as it will be presented is the one perceived by the author, and therefore comprises a very subjective selection of individual contributions to the field. Obviously, this is not the place to offer a review on chemometrics, let alone one that is restricted to a continent.The definition of chemometrics [I] comprises three distinct areas characterized by the key words "optimal measurements," "maximum chemical information" and, for analytical chemistry something that sounds like the synopsis of the other two: "optimal way [to obtain] relevant information." Information TheoryEckschlager and Stepanek [2][3][4][5] where q and p are the prior and posterior distribution of the analyte concentration for the specific cases of a rectangular prior distribution in (x,,x 2 ) and a Gaussian posterior with a standard deviation s determined from /A independent results. The penalty for an inaccurate analysis is considerable and can be expressed as (2) I (r;q,p)= I (q 11P)_nA with d the difference between obtained value and the true value of x. The concept has also been extended to multicomponent analysis and multimethod characterization.In the latter case, correlations between the information provided by the different methods need to be accounted for. Given the cost of and time needed for an analysis, information efficiency can be deduced in a straightforward manner [2]. Recently, work was published [5] suggesting the incorporation of various relevance co...

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Calculation of equilibrium constants from multiwavelength spectroscopic data—IIIModel-free analysis of spectrophotometric and ESR titrations

Cited by 475 publications

References 26 publications

The Thermodynamic Dissociation Constants of Clotrimazole, Terbinafine HCL, Acetylsalicylic Acid, Salicylic Acid, and Galanthamine by the Nonlinear Regression of Multiwavelength Spectrophotometric pH-Titration Data

The Thermodynamic Dissociation Constants of Clotrimazole, Terbinafine HCL, Acetylsalicylic Acid, Salicylic Acid, and Galanthamine by the Nonlinear Regression of Multiwavelength Spectrophotometric pH-Titration Data

Spectrophotometric Titration of Cobalt(II) with CaCl2 in Mixed Solvents of 2-Propanol and Water for the Analysis of the Extraction Mechanism of Cobalt(II) by Salting-out in the Presence of CaCl2

Chemometrics in Europe - Selected results

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