Effects of fluid filling techniques on reproducibility in capillary SFC

Porter, Nathan L.; Richter, Bruce E.; Bornhop, D. J.; Later, Douglas W.; Beyerlein, F. H.

doi:10.1002/jhrc.1240100815

Cited by 21 publications

(12 citation statements)

References 7 publications

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“…Reproducibility in peak area integration and retention times for normal alkanes (C22-C3,,) was severely compromised with the use of He head pressure [56]. The percent relative standard deviation (%RSD) for peak areas was approximately 12 times higher with the use of He head pressure than without He.…”

Section: P-x Plotmentioning

confidence: 97%

“…Gas-gas immiscibility of the second kind would produce an inhomogeneous mobile phase of gases with local variations in diffusion coefficients and viscosities. The distribution of the solutes through the mobile phase would be erratic and lead to irreproducible chromatographic performance, changes in t,, and peak areas [56]. Helium should not be used in CO, for SFC unless care is taken to ensure that conditions preclude phase separation.…”

Section: P-x Plotmentioning

confidence: 99%

See 1 more Smart Citation

Fluid phase equilibria in supercritical fluid chromatography with CO₂‐based mixed mobile phases: A review

Page

Sumpter

Lee

1992

J Microcolumn Separations

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Abstract. In supercritical fluid chromatography (SFC), cosolvents (modifiers) have been added to CO, in order to deactivate the analytical column and to improve the solvating power of CO, for extending the utility of SFC to polar and high molecular weight solutes. However, the use of modifiers has proven to be difficult, and irreproducibility in retention and selectivity is often observed.This comprehensive review focuses on the phase behavior of analytically useful C0,-based mixed mobile phases in SFC. All of the C0,-based mixed mobile phases which have been used in packed or open tubular column SFC are reviewed. All of the available fluid phase equilibria data for such binary fluids are discussed, and the P-T-x region which is applicable to SFC is compiled in both graphs and tables. Single phase regions (pressure and temperature) are listed by mol% modifier. However, only mixtures of CO, + benzene, + ethanol, + hexane, + methanol, or + toluene have enough P-T-x data points to enable extrapolation to any other conditions used in conventional SFC (0-20 mol% modifier, 40-400 atm, and 0-200°C). Problems associated with estimating the critical parameters of the pure components or the mixtures are reviewed. Phase transitions in the syringe pump, transfer lines, injector, column, and restrictor are delineated. Equilibration problems associated with the preparation of mixed mobile phases (premixed cylinders, liquid or gas phase saturation, and dual pumps with on-column mixing) and phase transitions during the operation of SFC instrumentation are discussed. Finally, future research needs are outlined.

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Section: P-x Plotmentioning

confidence: 97%

Section: P-x Plotmentioning

confidence: 99%

Fluid phase equilibria in supercritical fluid chromatography with CO₂‐based mixed mobile phases: A review

Page

Sumpter

Lee

1992

J Microcolumn Separations

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show abstract

“…12 The main characteristics of GA are information exchange and group search strategy among individuals in a group, that is to say, simulating the whole learning process of a group composed of individuals, and each individual represents a solution point in a given problem search space. 13 The optimization problem with more than one numerical objective is the multiobjective optimization problem. 14 The optimization calculation of carbon dioxide refrigerant charge in capillary radiant air conditioning system is a multiobjective optimization problem.…”

Section: Solution Of Multiobjective Optimization Problem Based On Gamentioning

confidence: 99%

Optimization of carbon dioxide refrigerant charge in capillary radiation air conditioning system based on genetic algorithm

2020

Asia-Pacific J Chem Eng

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The traditional capillary radiant air conditioning system based on back propagation (BP) neural network optimization model of carbon dioxide refrigerant filling, using neural network algorithm to optimize the carbon dioxide refrigerant filling, there is a big error. Aiming at this problem, a carbon dioxide refrigerant charging and filling optimization model in capillary radiant air conditioning system based on genetic algorithm (GA) is constructed. Based on the idea of solving multiobjective optimization problem with genetic algorithm, an adiabatic capillary steady‐state distribution model is constructed to analyze the change of refrigerant flow rate and critical temperature in capillary tube. Corresponding data samples, the GA‐BP neural network model is calculated based on the sample data, and the optimization of carbon dioxide refrigerant filling capacity is realized through the interpolation and extrapolation test model of condenser heat transfer and refrigerant outlet temperature. The experimental results show that the model has a significant application in optimizing the charging capacity of carbon dioxide refrigerant. The error of optimizing the charging capacity of carbon dioxide is small, and the error range is between (−0.03, 0.03).

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“…Syringe pumps may need to be cooled during filling, in order to fill the pump completely with liquid and not partly with gas. By reducing the temperature of the carbon dioxide from ambient to approximately 15 °C, Porter et al (1987) demonstrated that the pump filling increased from 60% to 90%. Cooling has another beneficial effect, to reduce the compressibility of the fluid.…”

Section: Syringe Pumpsmentioning

confidence: 99%

“…Particularly in laboratories with long supply lines from the cylinder to the pump, a helium head facilitates the filling. However, the introduction of helium in carbon dioxide has been shown to have adverse effects on chromatograpahic reproducibility, and other disadvantages as well (Porter et al, 1987). With an efficient cooling jacket, the pump cylinder can be filled without a helium head.…”

Section: Syringe Pumpsmentioning

confidence: 99%

Applications of Supercritical Fluids in Industrial Analysis

Dean¹

1993

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Effects of fluid filling techniques on reproducibility in capillary SFC

Cited by 21 publications

References 7 publications

Fluid phase equilibria in supercritical fluid chromatography with CO₂‐based mixed mobile phases: A review

Fluid phase equilibria in supercritical fluid chromatography with CO₂‐based mixed mobile phases: A review

Optimization of carbon dioxide refrigerant charge in capillary radiation air conditioning system based on genetic algorithm

Applications of Supercritical Fluids in Industrial Analysis

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Effects of fluid filling techniques on reproducibility in capillary SFC

Cited by 21 publications

References 7 publications

Fluid phase equilibria in supercritical fluid chromatography with CO2‐based mixed mobile phases: A review

Fluid phase equilibria in supercritical fluid chromatography with CO2‐based mixed mobile phases: A review

Optimization of carbon dioxide refrigerant charge in capillary radiation air conditioning system based on genetic algorithm

Applications of Supercritical Fluids in Industrial Analysis

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Product

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Fluid phase equilibria in supercritical fluid chromatography with CO₂‐based mixed mobile phases: A review

Fluid phase equilibria in supercritical fluid chromatography with CO₂‐based mixed mobile phases: A review