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Chemometrics separation optimization

Karlsson and Hermansson [30] used chemometrics for optimization of chiral separation of omeprazole and one of its metabolites on immobilized al-acid glycoprotein. Plasma was centrifuged at 2500 rpm and a portion (20-50 ji ) was injected into a 5-/rm Chiral-AGP column (10 cm x 4 mm) with al-acid glycoprotein immobilized to silica as a chiral stationary phase and acetonitrile-phosphate buffer of pH 5.7-7.2 as mobile phase (1 ml/min). Detection of omeprazole and its main metabolite, hydroxy-lated omeprazole, was performed at 302 nm. A statistical model was developed for the optimization of the operational parameters. The experimental data were evaluated with multivariate analyses column temperature and acetonitrile concentration were the most important variables for the enantioseparations. Complete enantiomeric separation for omeprazole and hydoxylated omeprazole was obtained within 15 min. [Pg.206]

However, final optimizations of these separations have not been realized or possible. Some workers have utilized pressurized flow to solve the problems of obtaining reasonable EOF without silanol-analyte interaction however, this does not solve the problem. It just forces the analyte to elute and approaches electro-HPLC, rather than true CEC. There are real differences between electro-HPLC, PEC, and CEC that need to be recognized. There does not, in general, seem to have been any serious attempt to utilize any chemometric software approaches in CEC/PEC for biopolymer separation optimizations or rationale for doing so. At this time, packings are simply used because they were on the shelf in a laboratory or commercially available and not necessarily because they were really the best for protein-peptide separations in PEC/CEC. There remains a need for research-oriented column choices from commercial vendors to avoid the need to pack capillaries in-house with commercial HPLC supports. [Pg.261]

In the context of chemometrics, optimization refers to the use of estimated parameters to control and optimize the outcome of experiments. Given a model that relates input variables to the output of a system, it is possible to find the set of inputs that optimizes the output. The system to be optimized may pertain to any type of analytical process, such as increasing resolution in hplc separations, increasing sensitivity in atomic emission spectrometry by controlling fuel and oxidant flow rates (14), or even in industrial processes, to optimize yield of a reaction as a function of input variables, temperature, pressure, and reactant concentration. The outputs ate the dependent variables, usually quantities such as instmment response, yield of a reaction, and resolution, and the input, or independent, variables are typically quantities like instmment settings, reaction conditions, or experimental media. [Pg.430]

The aim of this work is the optimization of distillation process using H SO for fluoride separation and potentiometric determination in anhydrite samples by means of chemometric tools. [Pg.271]

Procedures used vary from trial-and-error methods to more sophisticated approaches including the window diagram, the simplex method, the PRISMA method, chemometric method, or computer-assisted methods. Many of these procedures were originally developed for HPLC and were apphed to TLC with appropriate changes in methodology. In the majority of the procedures, a set of solvents is selected as components of the mobile phase and one of the mentioned procedures is then used to optimize their relative proportions. Chemometric methods make possible to choose the minimum number of chromatographic systems needed to perform the best separation. [Pg.95]

When from initial experiments, conditions that indicate the enantioselectivity of the system towards a given enantiomer pair or towards a limited series of substances are known, one might optimize their separation. To obtain optimal conditions, the different chemometric techniques used for method optimization in classic chromatographic or electrophoretic separations can also be applied for the chiral ones. Different experimental design approaches, using both screening and response surface designs can be In Reference 331, for... [Pg.487]

IPC-MS/MS was used to quantify heterocyclic aromatic amines in meat-based infant foods [30], The separation of biogenic amines was chemometrically optimized when they were determined in wines [31] a sensitive and selective method to determine 12 biogenic amines regardless of the characteristics of the vegetal food matrix was successfully validated [32], Determination of soybean proteins in commercial products was performed by fast IPC using an elution gradient and acetic acid as the IPR [33],... [Pg.163]

Fortunately, various chemometric-based techniques, including multivariate experimental design and data analysis techniques, have been devised to aid in optimizing the performance of systems and extend their separation capabilities. In broadest terms, chemometrics is a subdiscipline of analytical chemistry that uses mathematical, statistical, and formal logic to (10) ... [Pg.7]

Several studies have employed chemometric designs in CZE method development. In most cases, central composite designs were selected with background electrolyte pH and concentration as well as buffer additives such as methanol as experimental factors and separation selectivity or peak resolution of one or more critical analyte pairs as responses. For example, method development and optimization employing a three-factor central composite design was performed for the analysis of related compounds of the tetracychne antibiotics doxycycline (17) and metacychne (18). The separation selectivity between three critical pairs of analytes were selected as responses in the case of doxycycline while four critical pairs served as responses in the case of metacychne. In both studies, the data were htted to a partial least square (PLS) model. The factors buffer pH and methanol concentration proved to affect the separation selectivity of the respective critical pairs differently so that the overall optimized methods represented a compromise for each individual response. Both methods were subsequently validated and applied to commercial samples. [Pg.98]

OPTIMIZATION OF MICELLAR ELECTROKINETIC CHROMATOGRAPHY SEPARATION CONDITIONS BY CHEMOMETRIC METHODS... [Pg.113]

Chemometries has played two major roles in MEKC for analysis of the data collected from the separation and detection of analytes, and for efficient optimization of the separation conditions. Regarding data analysis, chemometrics can allow deconvolution of poorly resolved peaks (15,16) and quantification of the corresponding analytes. Chemometrics can also be employed for multivariate calibration (17), characterization of complex samples, and to study peak purity. Sentellas and Saurina have recently reviewed the role of chemometrics applied to data analysis in CE (18). For MEKC in particular, chemometrics has been used more widely as a tool for optimization of separation conditions. The focus of this chapter is to exemplify the utility of chemometric methods for the optimization of separation conditions in MEKC. [Pg.114]

TABLE 5.1. A summary of factors, responses, chemometric designs and methods, and validation criteria nsed by different gronps for the optimization of the separation of varions samples by MEKC... [Pg.117]

An additional chemometrical approach for this optimization is the use of ANNs (8,9), which consist of a large number of simple, highly interconnected processing elements in an architecture inspired on the brain s structure. A relatively large number of experimental data is frequently necessary to train the network so that it learns the behavior of data and can develop further predictions. In this sense, the use of EDs provides an appropriate source of experimental data that can greatly help to train the ANN. The combination of both approaches, ED and ANNs, constitutes an effective strategy toward optimization of CE separation that has not been fully studied. [Pg.135]

One of the current trends in separation science is the development of comprehensive or multidimensional separation systems, in which CE and CE-MS are also achieving relative importance. Chemometric approaches like the ones described in this chapter will surely be of great help for the optimization of these more complicated separation systems. Current trends toward miniaturization in separation science are also well known. Ultrafast separations, extremely low sample requirements, and automation of the arrangement are some of these goals. Chemometrics will surely provide an interesting and challenging approach for the optimization of separation conditions in these miniaturized systems, including microchips for years to come. [Pg.165]

Optimization of separation conditions using chemometric approaches 231... [Pg.227]

OPTIMIZATION OF SEPARATION CONDITIONS USING CHEMOMETRIC APPROACHES... [Pg.231]


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