Isocratic and gradient elution chromatography: A comparison in terms of speed, retention reproducibility and quantitation

Schellinger, Adam P.; Carr, Peter W.

doi:10.1016/j.chroma.2006.01.047

Cited by 103 publications

(69 citation statements)

References 30 publications

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“…The best "traditional" multi-segment gradient profile (determined by a starting composition 0 and a value for ˇ and t G for each segment) was determined via a similar grid search. Based on our own findings and these of Concha-Herrara et al [12], only 4-segment gradients were considered as these give the best compromise between the achievable selectivity (in gradient elution this is the ratio between the apparent gradient retention factors k eff,1 /k eff,2 [16][17][18][19][20][21][22][23][24][25][26][27]) and the required search time. The grid search was conducted considering different starting concentrations %B between 5 and 95% (step size of 0.5%) and a number of ˇ-and t G -values for each of the 4 segments (ˇ going from 0.001 to 0.2, corresponding to 0.1 to 20%B/min, i.e., ln(ˇ) between −6.9 and −0.70 and t G /t 0 between 1 and 12).…”

mentioning

confidence: 99%

Enhanced selectivity and search speed for method development using one-segment-per-component optimization strategies

Tyteca

Vanderlinden

Favier

et al. 2014

Journal of Chromatography A

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a b s t r a c tLinear gradient programs are very frequently used in reversed phase liquid chromatography to enhance the selectivity compared to isocratic separations. Multi-linear gradient programs on the other hand are only scarcely used, despite their intrinsically larger separation power. Because the gradient-conformity of the latest generation of instruments has greatly improved, a renewed interest in more complex multisegment gradient liquid chromatography can be expected in the future, raising the need for better performing gradient design algorithms. We explored the possibilities of a new type of multi-segment gradient optimization algorithm, the so-called "one-segment-per-group-of-components" optimization strategy. In this gradient design strategy, the slope is adjusted after the elution of each individual component of the sample, letting the retention properties of the different analytes auto-guide the course of the gradient profile. Applying this method experimentally to four randomly selected test samples, the separation time could on average be reduced with about 40% compared to the best single linear gradient. Moreover, the newly proposed approach performed equally well or better than the multi-segment optimization mode of a commercial software package. Carrying out an extensive in silico study, the experimentally observed advantage could also be generalized over a statistically significant amount of different 10 and 20 component samples. In addition, the newly proposed gradient optimization approach enables much faster searches than the traditional multi-step gradient design methods.

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mentioning

confidence: 99%

Enhanced selectivity and search speed for method development using one-segment-per-component optimization strategies

Tyteca

Vanderlinden

Favier

et al. 2014

Journal of Chromatography A

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“…Method validation include assessment of the parameters such as precision, linearity, accuracy, limit of detection, limit of quantification, specificity, range and robustness of the method (ICH, 2005;Magnusson & Ornemark, 2014). Schellinger & Carr (2006) found that gradient elution gave a shorter overall analysis with similar resolution compared to isocratic elution. On the other hand isocratic elution remain preferable when the sample contains less than ten weakly retained components (Schellinger & Carr, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…Schellinger & Carr (2006) found that gradient elution gave a shorter overall analysis with similar resolution compared to isocratic elution. On the other hand isocratic elution remain preferable when the sample contains less than ten weakly retained components (Schellinger & Carr, 2006). This study aimed at establishing an optimized HPLC-UV method for separation, detection and quantification of estrogens hormones from low quality water particularly from wastewater stabilization ponds.…”

Section: Introductionmentioning

confidence: 99%

Optimized HPLC -UV Method for Separation, Detection and Quantification of Endocrine Disrupting Estrogens in Low Quality Water

Msigala¹,

Mabiki²,

Styrishave³

et al. 2017

IJC

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Endocrine disrupting estrogens are emerging contaminants in aquatic ecosystems and environment in general. There are no guidelines for routine monitoring of these chemicals, despite the existing evidences of their adverse health effect to living organisms at low concentrations. This study aimed at developing and validating an optimized HPLC-UV method for detection and quantification of estradiol and ethinylestradiol. Isocratic elution was used for separation and detection of ethinylestradiol and estradiol. The mobile phase was applied with A; water B; acetonitrile (50:50) at flow rate of 0.7mL/min and injection volume 10mL. The precision and accuracy of the method were within the acceptable range. Relative standard deviation of peak area for E2 ranged from 1.373 to 3.668%, and for EE2 ranged from 0.829 to 6.495 %. The percentage recovery for E2 ranged from 82.3 to 99.84 %, and for EE2 ranged from 84.6 to 103.52 %. Linearity of the method was realized at range of 2.5 to 50 ng/mL and 100 to 1000 ng/mL for both E2 and EE2. The linear regression coefficients were 0.9979 and 0.9973 for E2 whereas for EE2 were 0.9983 and 0.9976. Limit of detection were found to be 0.05 ng/mL and 0.08 ng/mL for E2 and EE2 respectively. The obtained limits of quantification were 0.18 and 0.28 ng/mL for E2 and EE2 respectively. In untreated sewage the concentrations of E2 and EE2 were 0.28 ng/ml and 0.18 ng/ml respectively. But in subsequent wastewater stabilization ponds the concentrations were below detection limit. Therefore, the optimized HPLC-UV method is suitable for detection and quantification of endocrine disrupting estrogens when a level of pollution is at least 0.15 ng/ml. At low extent of pollution would require use of the method in conjunction with ELISA technique.

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“…The cyclic operation of HPLC separation processes in batch elution mode imposes adequate retention time repeatability by conditioning the column to the initial modifier concentration prior to the subsequent injection [65,66]. In the scope of chromatographic separations, cyclic-steady-state (CSS) prediction has previously only been applied to continuous simulated moving bed (SMB) [11,18,67] and multicolumn counter-current solvent gradient purification (MCSGP) [68] processes.…”

Section: Problem Formulationmentioning

confidence: 99%

Methods and Tools for Robust Optimal Control of Batch Chromatographic Separation Processes

et al. 2015

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This contribution concerns the development of generic methods and tools for robust optimal control of high-pressure liquid chromatographic separation processes. The proposed methodology exploits a deterministic robust formulation, that employs a linearization of the uncertainty set, based on Lyapunov differential equations to generate optimal elution trajectories in the presence of uncertainty. Computational tractability is obtained by casting the robust counterpart problem in the framework of bilevel optimal control where the upper level concerns forward simulation of the Lyapunov differential equation, and the nominal open-loop optimal control problem augmented with the robustified target component purity inequality constraint margin is considered in the lower level. The lower-level open-loop optimal control problem, constrained by spatially discretized partial differential equations, is transcribed into a finite dimensional nonlinear program using direct collocation, which is then solved by a primal-dual interior point method. The advantages of the robustification strategy are highlighted through the solution of a challenging ternary complex mixture separation problem for a hydrophobic interaction chromatography system. The study shows that penalizing the changes in the zero-order hold control gives optimal solutions with low sensitivity to uncertainty. A key result is that the robustified general elution trajectories outperformed the conventional linear trajectories both in terms of recovery yield and robustness.

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Isocratic and gradient elution chromatography: A comparison in terms of speed, retention reproducibility and quantitation

Cited by 103 publications

References 30 publications

Enhanced selectivity and search speed for method development using one-segment-per-component optimization strategies

Enhanced selectivity and search speed for method development using one-segment-per-component optimization strategies

Optimized HPLC -UV Method for Separation, Detection and Quantification of Endocrine Disrupting Estrogens in Low Quality Water

Methods and Tools for Robust Optimal Control of Batch Chromatographic Separation Processes

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