Theories of chromatography Rate theoryand plate theory.pptx

Theories of chromatography Rate theory and plate theory B.pharm instrumemtal analysis And M.pharm Mpat

1. NAME = KUNAL ANIL SURYAWANSHI ROLL NO = 61 SUBJECT= INSTRUMENTAL ANALYSIS ) BATCH = C COLLEGE = MGV’S S.P.H. COLLEGE OF PHARMACY MALEGAON FINAL YEAR B.PHARMACY SEM 7

2. THEORIES OF CHROMATOGRAPHY

3. Chromatography technique and the column efficiency are defined by the plate's concepts and rate theory of chromatography.

4. The rate theory of chromatography is important for chromatographic analysis. The theories help understand how the analytes move in the stationary phase as the mobile phase flows through it.  The rate theory of chromatography defines the activity in a chromatography column. It shows that when solute elutes out of the column, it impacts the band shape and is affected by the elution rate. Rate Theory of Chromatography

5. Rate Theory of Chromatography The rate theory provides information about the shape and breadth of the elution bands as the mobile phase migrates and flows through a column. It helps understand the process of peak dispersion and factors impacting band broadening.  It gives a realistic explanation of the process occurring in a chromatographic column. It considers and measures the time taken by the solute to equilibrate between the stationary and mobile phase

6. Rate Theory of Chromatography It considers the rate of elution on the resulting band shape or the chromatographic peak.  The rate theory of chromatography is expressed mathematically  by the van Deemter equation. The equation helps calculate the variance per unit length of a column in terms of mobile phase velocity and analyte properties. The relationship between a column’s efficiency and the mechanism behind band broadening is described by the Van Deemter equation.

7. It is represented by              HETP = A + B/u (C s  + C m ). u  Where A = Eddy diffusion parameter B = diffusion co-efficient of eluting particles in the longitudinal direction C = Resistance to mass transfer coefficient of the analyte between the stationary and mobile phase  u = speed C m  = dispersive convection in the mobile phase C s  = sorption, and desorption of the solute from the stationary phase  HETP is the measure of zone broadening. Rate Theory of Chromatography

8. Plate Theory of Chromatography

9. Plate Theory of Chromatography The  plate theory of chromatography is an older concept and does not give a realistic view of column efficiency and what is happening in the column. The theory was integrated into the chromatography technique in 1941 by Martin and Synge. According to the model, the chromatographic column consists of separate layers known as the theoretical plates. These plates are hypothetical zones or stages that help in establishing an equilibrium between two phases. 

10. Plate Theory of Chromatography Unlike the rate theory of chromatography, it gives a hypothetical picture of the separation of the analytes in a chromatographic column. These plates provide separation equilibrium of the sample between the mobile and stationary phase.  As the mobile phase passes through the stationary phase in a column, the analytes in the mobile phase are distributed between the two phases establishing an equilibrium

11. Plate Theory of Chromatography ● Once the equilibrium is obtained, the solute from the mobile phase is carried from one plate to another and continues till it is eluted out of the column. The nature and solute type determine the retention time and peak width.  As the theoretical plate number increases in the column, it narrows the solute peak and provides better resolution between different components in the sample. 

12. The number of the theoretical plate in a column is represented by N. The efficiency of the column is represented by HETP (Height Equivalent to a Theoretical Plate). A measure of the efficiency of a chromatography column is the height equivalent to a theoretical plate or plate height. Equation : H =L/N WHERE H= Plate height L= length of column N= Number of therotical plate P late Theory of Chromatography

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