Chromatography system
First Claim
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1. The system for chromatographic analysis comprising:
- (a) a column having a stationary substrate phase therein;
(b) said column also having a mobile transport phase having a capacity factor representing the ability of the mobile phase to transport a species under analysis through said column;
(c) detector means for dynamically measuring the time of migration of said species through said column;
(d) reporting means responsive to said dynamic migration time measurements for providing a chromatogram having data corresponding to said species; and
(e) computer means for processing said data for optimizing the relationship between resolution of the chromatogram provided by said reporting means and time;
said computer means comprising(i) means responsive to said chromatogram for calculating the capacity factor for each of the species under analysis, and(ii) means responsive to the capacity factor and physical parameters of the system including the column length and type of substrate and properties of the mobile transport phase selected from the group consisting of density, temperature and composition of the mobile phase.
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Abstract
A system (method and apparatus) for optimizing the relationship between resolution and time in chromatograms, especially chromatograms obtained by supercritical fluids (CSF) chromatography. The pressure or temperature or fluid density of the solution caring the material under analysis is varied dynamically under computer control to provide an optimum capacity factor for a particular transporting fluid in a particular chromatographic system to obtain the resolution of interest in the shortest period of time.
38 Citations
21 Claims
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1. The system for chromatographic analysis comprising:
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(a) a column having a stationary substrate phase therein; (b) said column also having a mobile transport phase having a capacity factor representing the ability of the mobile phase to transport a species under analysis through said column; (c) detector means for dynamically measuring the time of migration of said species through said column; (d) reporting means responsive to said dynamic migration time measurements for providing a chromatogram having data corresponding to said species; and (e) computer means for processing said data for optimizing the relationship between resolution of the chromatogram provided by said reporting means and time;
said computer means comprising(i) means responsive to said chromatogram for calculating the capacity factor for each of the species under analysis, and (ii) means responsive to the capacity factor and physical parameters of the system including the column length and type of substrate and properties of the mobile transport phase selected from the group consisting of density, temperature and composition of the mobile phase. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of optimizing the relationship between resolution and time in a SCF chromatographic system having a column along which j analyte components are transported by a SFC mobile phase to provide a chromatogram having peaks separate by distances xj (t) corresponding to the time for each of the j components to be transported to a downstream end of said column certain resolution in a optimally short period of time, comprising the steps of:
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inputting an initial density profile ρ
(t) over time for the supercritical fluid mobile phase;measuring xj (t) from said peaks; integrating the following modeling equation for the number of the analyte components j using the initial density profile;
##EQU27## where t=timex=axial length down the column m0 =input mass flow rate to column A=cross-sectional area of the bed L=length of column ρ
=mobile phase fluid density of the SCFj=number of species being separated kj=capacity factor (thermodynamic partition coefficient) for the j component integrating the following Lagrangian multipliers backward in time over [t0,tf ] using the density profile (ρ
(t)) and the peaks xj (t);
##EQU28## calculating a correction in density profile using the following equation;
##EQU29## and changing the density of said SCF in said column according to said correction. - View Dependent Claims (14, 15)
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16. A method for calculating an optimum temperature profile for a gaseous transport fluid which transports along a column of analyte components to be analyzed to obtain a chromatogram with peaks corresponding to the j components particular resolution in the shortest time in a gas chromatographic system having said column, comprising:
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initializing the system by inputting an initial temperature profile T(t) over the time interval [t0,tf ] for the gas; measuring the distance xj (t) which corresponds to the time which it takes for each of the j components to travel along the column by the separation distance of the peaks; integrating the following modeling equation for each component j using the initial temperature profile;
##EQU31## where t=timex=axial length down the column m0 =input mass flow rate to column A=cross-sectional area of the bed L=length of column ρ
=mobile phase fluid density of the SCFj=number of species being separated kj=capacity factor (thermodynamic partition coefficient) for the j component integrating the following Lagrangian multipliers backward in time over [t0,tf ] using the temperature profile (T(t)) and the peaks xj (t);
##EQU32## calculating a correction in temperature profile using the following equation;
##EQU33## and changing the temperature of the gas in the column in accordance with the correction. - View Dependent Claims (17, 18)
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19. A method for calculating an optimum composition profile of a liquid transport fluid to obtain a particular resolution in the shortest time in a liquid chromatographic system which provides a chromatogram having a plurality of spaced peaks corresponding to a plurality j of analyte components which are transported along a column, the peaks being separated by distances xj(t) which correspond to the time it takes for each of the j components to be transported along the column, comprising:
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initializing the system with an initial composition profile c(t) over time for the liquid transport fluid; measuring xj(t) from the peaks; integrating the following modeling equation for each component j using the initial composition profile;
##EQU35## where t=timex=axial length down the column m0 =input mass flow rate to column A=cross-sectional area of the bed L=length of column ρ
=mobile phase fluid density of the SCFj=number of species being separated kj=capacity factor (thermodynamic partition coefficient) for the j component integrating the following Langrangian multipliers backward in time over [t0,tf ] using the composition profile (c(t)) and the peaks xj (t);
##EQU36## calculating a correction composition profile using the following equation;
##EQU37## and changing the composition of said liquid in accordance with said correction. - View Dependent Claims (20, 21)
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Specification