A chromatographic response function for automated optimization of separations

Wegscheider, Wolfhard; Lankmayr, Ernst; Budna, K. W.

doi:10.1007/bf02260283

Cited by 31 publications

(5 citation statements)

References 30 publications

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“…This parameter is commonly used as the optimization criterion to compare selectivity in the chosen TLC systems [12, 21]. Individual micro-TLC chromatographic profiles composed of multiple spots were compared using Δ hR F product (ΠΔ hR F ) similarly to optimization criteria proposed for column chromatography [22, 23]. In the present work logarithmic form of Δ hR F product was applied due to wide (few factors) range of resulting ΠΔ hR F values calculated for the spots visualized in studied samples.…”

Section: Methodsmentioning

confidence: 99%

Micro-TLC Approach for Fast Screening of Environmental Samples Derived from Surface and Sewage Waters

et al. 2013

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In this work we demonstrated analytical capability of micro-planar (micro-TLC) technique comprising one and two-dimensional (2D) separation modes to generate fingerprints of environmental samples originated from sewage and ecosystems waters. We showed that elaborated separation and detection protocols are complementary to previously invented HPLC method based on temperature-dependent inclusion chromatography and UV-DAD detection. Presented 1D and 2D micro-TLC chromatograms of SPE (solid-phase extraction) extracts were optimized for fast and low-cost screening of water samples collected from lakes and rivers located in the area of Middle Pomerania in northern part of Poland. Moreover, we studied highly organic compounds loaded in the treated and untreated sewage waters obtained from municipal wastewater treatment plant “Jamno” near Koszalin City (Poland). Analyzed environmental samples contained number of substances characterized by polarity range from estetrol to progesterone as well as chlorophyll-related dyes previously isolated and pre-purified by simple SPE protocol involving C18 cartridges. Optimization of micro-TLC separation and quantification protocols of such samples were discussed from the practical point of view using simple separation efficiency criteria including total peaks number, log(product ΔhRF), signal intensity and peak asymmetry. Outcomes of the presented analytical approach, especially using detection involving direct fluorescence (UV366/Vis) and phosphomolybdic acid (PMA) visualization are compared with UV-DAD HPLC-generated data reported previously. Chemometric investigation based on principal components analysis revealed that SPE extracts separated by micro-TLC and detected under fluorescence and PMA visualization modes can be used for robust sample fingerprinting even after long-term storage of the extracts (up to 4 years) at subambient temperature (−20 °C). Such approach allows characterization of wide range of sample components that are present in given extract in high and middle concentration range. Due to protocol simplicity and low cost of analysis this method can be useful for preliminary sample screening.

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Section: Methodsmentioning

confidence: 99%

Micro-TLC Approach for Fast Screening of Environmental Samples Derived from Surface and Sewage Waters

et al. 2013

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“…The theory of chromatography has been applied for over 40 years to improving separations of solution components (1, 2) and to the dependence of degree of separation on column efficiency and selectivity (2)(3)(4). Most measures of the degree of separation have been limited to peaks of Gaussian (1,2,5) or similar shapes (6)(7)(8)(9). Non-Gaussian peak shapes obtained in chromatographic systems with nonlinear isotherms or slow retention kinetics sometimes result from unavoidable system conditions such as slow protein diffusion, low stationary-phase capacity, or stationary-phase inhomogeneity.…”

Section: Citedmentioning

confidence: 99%

“…In other work Schoenmakers offers firstorder corrections to Ra for the effects of a very large interfering peak (16). The peak separations of Kaiser (17) and related measures (7,8) are very useful to describe the degree of separation for Gaussian peak shapes, but their usefulness is not easily extended to peaks with radically non-Gaussian shapes. The linear algebraic methods of Corry et al (18) are designed to measure the efficiency of a single sorting process.…”

Section: Citedmentioning

confidence: 99%

Normalized measure of overlap between non-Gaussian chromatographic peaks

Dose¹,

Guiochon²

1990

Anal. Chem.

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“…Wegscheider et al (6) developed a response function that operates differently than those mentioned above, i.e., as a product rather than a summation, and it takes into account the noise level of the chromatogram. In addition, there have also been peak-counting algorithms.…”

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confidence: 99%

“…In addition, peak crossing causes problems since the function is zero for totally overlapped pairs of peaks, causing false optima. The function of Wegscheider et al (6), even though it operates as a product of the individual peak separations rather than the sum of natural logarithms, suffers from the same problems. Furthermore, for all of the above functions, the number of components being separated should be known in order to ensure proper operation of the function.…”

mentioning

confidence: 99%

Separation function for measuring the information in complex chromatograms

Hare¹,

Rogers²

1985

Anal. Chem.

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The separation function for use In the optimization of complex separations relates the Information content of a chromatogram to the number and the extent of resolution between adjacent peaks. Each fully resolved peak Is arbitrarily assigned 2.0 bits of Information while partially resolved peaks are assigned 1 to 2 bits depending upon the depth of the valley between them. Pairs that give no valley but are detectable using a second-derivative method are assigned 0.5 bit. No a priori Information Is needed so the separation function may be easily Incorporated Into existing optimization schemes.Recently, the optimization of chromatographic separations has moved away from conventional methods in which a chromatographer uses experience and intuition to judge the

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A chromatographic response function for automated optimization of separations

Cited by 31 publications

References 30 publications

Micro-TLC Approach for Fast Screening of Environmental Samples Derived from Surface and Sewage Waters

Micro-TLC Approach for Fast Screening of Environmental Samples Derived from Surface and Sewage Waters

Normalized measure of overlap between non-Gaussian chromatographic peaks

Separation function for measuring the information in complex chromatograms

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