Mathematical functions for the representation of chromatographic peaks

Marco, Valerio Di; Bombi, G. Giorgio

doi:10.1016/s0021-9673(01)01136-0

Cited by 194 publications

(126 citation statements)

References 180 publications

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“…There exists a range of possible peak representations as described in ref 20. In this paper the most straight forward Gaussian representation is initially demonstrated, although this does not factor in skew within the peak.…”

Section: Methodsmentioning

confidence: 96%

Principal Component Score Modeling for the Rapid Description of Chromatographic Separations

et al. 2008

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This paper describes the use of Principal Component Analysis (PCA) as a tool for modeling chromatographic separations. PCA is an analytical technique developed to extract key information out of large data sets and to develop relationships and correlations. The basis of the proposed model is the use of PCA to correlate experimental chromatographic data across different process variables or scales. The generated correlations are then used to provide for the simulation of additional chromatographic runs not included in the initial dataset. The approach is demonstrated by application to the cation exchange separation of a four protein component feed comprising ovalbumin, ovatransferrin, lysozyme, and myoglobin. A good fit between modeled and experimental data was found, and the ability of the method to model additional chromatographic separations not within the original dataset is demonstrated. The technique has the potential to accommodate changing system variables such as column dimensions as well as process variables including sample volume and salt gradient. It provides a potentially powerful tool for the rapid investigation of scale-up effects and for the minimization of the material inventories needed for such studies.

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Section: Methodsmentioning

confidence: 96%

Principal Component Score Modeling for the Rapid Description of Chromatographic Separations

et al. 2008

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“…The area of the first eluting Mn and Ca peak was determined by fitting the chromatographic data for Mn and Ca ion intensities. It was assumed that each peak can be fitted using the commonly used EMG profile described by Equation 1 (Di Marco and Bombi, 2001):…”

Section: Peak Fitting and Optimization Procedures For Mn To Ca Ratio Dmentioning

confidence: 99%

“…To obtain an accurate estimate of the molar Mn to Ca ratio, peak fitting was performed using sums of Exponentially Modified Gaussian (EMG) profiles (Supplemental Fig. S3; Di Marco and Bombi, 2001). Assuming that the largest Mn peak and the first Ca peak, with a molecular mass about 900 kD, represent active PSII supercomplexes, the area of the corresponding fitted peaks resulted in a molar Mn to Ca ratio of 4.1 6 0.6 (n = 4).…”

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confidence: 99%

Metal Binding in Photosystem II Super- and Subcomplexes from Barley Thylakoids

et al. 2015

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Metals exert important functions in the chloroplast of plants, where they act as cofactors and catalysts in the photosynthetic electron transport chain. In particular, manganese (Mn) has a key function because of its indispensable role in the water-splitting reaction of photosystem II (PSII). More and better knowledge is required on how the various complexes of PSII are affected in response to, for example, nutritional disorders and other environmental stress conditions. We here present, to our knowledge, a new method that allows the analysis of metal binding in intact photosynthetic complexes of barley (Hordeum vulgare) thylakoids. The method is based on size exclusion chromatography coupled to inductively coupled plasma triple-quadrupole mass spectrometry. Proper fractionation of PSII super-and subcomplexes was achieved by critical selection of elution buffers, detergents for protein solubilization, and stabilizers to maintain complex integrity. The applicability of the method was shown by quantification of Mn binding in PSII from thylakoids of two barley genotypes with contrasting Mn efficiency exposed to increasing levels of Mn deficiency. The amount of PSII supercomplexes was drastically reduced in response to Mn deficiency. The Mn efficient genotype bound significantly more Mn per unit of PSII under control and mild Mn deficiency conditions than the inefficient genotype, despite having lower or similar total leaf Mn concentrations. It is concluded that the new method facilitates studies of the internal use of Mn and other biometals in various PSII complexes as well as their relative dynamics according to changes in environmental conditions.

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“…This characteristic bell protection profile can be described by many bell functions (Di Marco, 2001). After testing several equations, the generalized exponential function without intercept (also called the modified Weibull distribution function) was found to be the most satisfactory one with least number of parameters and highest accuracy:…”

Section: Standardizations and Fittingsmentioning

confidence: 99%

Analytical criteria to quantify and compare the antioxidant and pro-oxidant capacity in competition assays: The bell protection function

Prieto¹,

Murado²,

Vázquez³

et al. 2014

Food Research International

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Publication informationFood Research International, 60 (2014): 48-58 Publisher ElsevierItem record/more information http://hdl.handle.net/10197/6178 Publisher's statement þÿ T h i s i s t h e a u t h o r s v e r s i o n o f a w o r k t h a t w a s a c c e p t e d f o r p u b l i c a t i o n i n F o o d R e s e a r c hInternational. Changes resulting from the publishing process, such as peer review, editing, ABSTRACTThe development of a convenient mathematical application for testing the antioxidant and prooxidant potential of standard and novel therapeutic agents is essential for the research community and food industry in order to perform more precise evaluations of products and processes. In this work, a simple non-linear dose-time tool to test the effectiveness of compounds for competitive assays is presented. The model helps to describe accurately the antioxidant and pro-oxidant response as a function of time and dose by two criteria values and allows one to perform easily comparisons of both capacities from different compounds. The quantification procedure developed was applied to two well known in vitro competition assays, the β-carotene and crocin bleaching asymptotic reactions. The dose-time dependency of the response of commercial antioxidants and some expected pro-oxidant compounds was evaluated in this study and the results showed low experimental error. In addition, as an illustrative example of the capabilities of the criteria proposed, the quantification of the combined effect of an antioxidant and a pro-oxidant was analyzed. Afterwards, the model was verified for other relevant competitive methods, using available experimental data from the bibliography. Its application is simple, it provides parametric estimates which characterize the response, and it facilitates rigorous comparisons among the effects of different compounds and experimental approaches. In all experimental data tested, the calculated parameters were always statistically significant (Student's t-test, α = 0.05), the equations were consistent (Fisher's F-test) and the goodness of fit coefficient of determination was higher than 0.98.

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Mathematical functions for the representation of chromatographic peaks

Cited by 194 publications

References 180 publications

Principal Component Score Modeling for the Rapid Description of Chromatographic Separations

Principal Component Score Modeling for the Rapid Description of Chromatographic Separations

Metal Binding in Photosystem II Super- and Subcomplexes from Barley Thylakoids

Analytical criteria to quantify and compare the antioxidant and pro-oxidant capacity in competition assays: The bell protection function

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