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Curtain Flow Column: Optimization of Efficiency and Sensitivity
Published on: June 12, 2016
Comparison of various second-dimension gradient types in comprehensive two-dimensional liquid chromatography
Pavel Jandera1, Tomás Hájek, Petr Cesla
1Department of Analytical Chemistry, University of Pardubice, Pardubice, Czech Republic. pavel.jandera@upce.cz
Journal of Separation Science
|March 24, 2010
Summary
Gradient elution in comprehensive LCxLC improves peak capacity. Different gradient types were compared, revealing that porous shell columns enable faster, more efficient separations by controlling compound lipophilicity.
Area of Science:
- Analytical Chemistry
- Chromatography
- Separation Science
Background:
- Gradient elution significantly enhances peak capacity compared to isocratic conditions in liquid chromatography (LC).
- In comprehensive two-dimensional LC (LCxLC), the second dimension separation is time-constrained, necessitating optimized gradient strategies.
Purpose of the Study:
- To compare different types of second-dimension gradients in orthogonal LCxLC separations.
- To investigate the impact of gradient type on separation performance metrics like bandwidth, peak capacity, and time.
- To evaluate the utility of porous shell fused-core C18 columns for fast second-dimension separations.
Main Methods:
- Orthogonal LCxLC separations were performed using a polyethylene glycol column in the first dimension and two types of porous shell fused-core C18 columns (Ascentis Express, Kinetex) in the second dimension.
- Three gradient types were compared: 'full in fraction', 'segment in fraction', and 'continuously shifting'.
- The effects of gradient type on bandwidth, theoretical peak capacity, separation time, and column pressure were analyzed.
Main Results:
- Porous shell columns facilitated narrow bandwidths and rapid second-dimension separations at moderate pressures, reducing overall separation time.
- The type of gradient program critically influenced the range of compound lipophilicity separable in the second dimension.
- Calibration using alkylbenzene standards allowed for the design of separation conditions to prevent wrap-around issues.
Conclusions:
- Gradient optimization in the second dimension of LCxLC is crucial for maximizing separation efficiency and peak capacity.
- Porous shell fused-core columns are well-suited for fast, high-performance second-dimension separations in LCxLC.
- Understanding and controlling the lipophilicity range through gradient programming ensures comprehensive sample coverage and avoids inter-fraction contamination.
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