Abstract An electrophoretic scattering apparatus for determining the electrophoretic mobility and diffusion coefficient of a macromolecular polymer in solution is disclosed. More particularly, the charged macromolecules are driven through the solution by an electric field developed between two charged electrodes in a modified electrophoretic cell. The electric field is alternately enabled and disabled during the determination to prevent excessive heat build-up in the solution and the resultant convection of macromolecules which would distort the measurements. A laser provides an incident light beam which is passed through the cell perpendicular to the direction of the macromolecule flow so that the autocorrelation function or, alternatively, the frequency spectrum of the light scattered from the macromolecules can be observed at low scattering angles. The scattered light, in addition to having a frequency distribution curve proportional to the diffusion coefficient of the macromolecules, is Doppler shifted by an amount proportional to the electrophoretic mobility of the macromolecule in the scattering region. Because each species of polymers has a unique electrophoretic mobility and hence Doppler shift, the apparatus is useful in quantitatively analyzing a mixture of several different polymers in solution (e.g., life-like enzymes such as blood) to identify the polymers and their relative concentrations.
A METHOD OF DETERMINING THE ELECTROPHORETIC MOBILITY AND DIFFUSION COEFFICIENT OF A MACROMOLECULAR POLYMER IN SOLUTION, WHICH METHOD COMPRISES THE FOLLOWING STEPS: ESTABLISHING AN ELECTRIC FIELD ACROSS SAID SOLUTION TO MOVE SAID MACROMOLECULES THROUGH SAID SOLUTION IN A DIRECTION PARALLEL WITH SAID ELECTRIC FIELD AT A VELOCITY PROPORTIONAL TO SAID ELECTROPHORETIC MOBILITY; APPLYING A LIGHT BEAM COMPRISING MONOCHROMATIC ELECTROMAGNETIC RADIATION INCIDENT ON SAID MACROMOLECULES; DETECTING SAID LIGHT BEAM SCATTERED BY SAID MACROMOLECULES; HETERODYNING SAID DETECTED SCATTERED LIGHT BEAM WITH SAID INCIDENT LIGHT BEAM TO PRODUCE BEAT FREQUENCY SIGNALS; AND ANALYZING SAID BEAT FREQUENCY SIGNALS TO DETERMINE THE DOPPLER SHIFT OF SAID SCATTERED LIGHT BEAM WHICH IS REPRESENTATIVE OF SAID ELECTROPHORETIC MOBILITY AND TO DETERMINE THE FREQUENCY DISTRIBUTION OF SAID SCATTERED LIGHT BEAM WHICH IS REPRESENTATIVE OF SAID DIFFUSION COEFFICIENT.
Claim 2
Independent Claim
129 words
A METHOD OF DETERMINING THE ELECTROPHORETIC MOBILITY AND DIFFUSION COEFFICIENT OF A MACROMOLECULAR POLYMER IN SOLUTION, WHICH METHOD COMPRISES THE FOLLOWING STEPS: ESTABLISHING AN ELECTRIC FIELD ACROSS SAID SOLUTION TO MOVE SAID MACROMOLECULES THROUGH SAID SOLUTION IN A DIRECTION PARALLEL WITH SAID ELECTRIC FIELD AT A VELOCITY PROPORTIONAL TO SAID ELECTROPHORETIC MOBILITY; APPLYING A LIGHT BEAM COMPRISING MONOCHROMATIC ELECTROMAGNETIC RADIATION INCIDENT ON SAID MACROMOLECULES; DETECTING SAID LIGHT BEAM SCATTERED BY SAID MACROMOLECULES; HETERODYNING SAID DETECTED SCATTERED LIGHT BEAM WITH SAID INCIDENT LIGHT BEAM TO PRODUCE BEAT FREQUENCY SIGNALS; AND ANALYZING SAID BEAT FREQUENCY SIGNALS TO DETERMINE THE DOPPLER SHIFT OF SAID SCATTERED LIGHT BEAM WHICH IS REPRESENTATIVE OF SAID ELECTROPHORETIC MOBILITY AND TO DETERMINE THE FREQUENCY DISTRIBUTION OF SAID SCATTERED LIGHT BEAM WHICH IS REPRESENTATIVE OF SAID DIFFUSION COEFFICIENT.
Claim 3
Independent Claim
129 words
A method of determining the electrophoretic mobility and diffusion coefficient of a macromolecular polymer in solution, which method comprises the following steps: establishing an electric field across said solution to move said macromolecules through said solution in a direction parallel with said electric field at a velocity proportional to said electrophoretic mobility; applying a light beam comprising monochromatic electromagnetic radiation incident on said macromolecules; detecting said light beam scattered by said macromolecules; heterodyning said detected scattered light beam with said incident light beam to produce beat frequency signals; and analyzing said beat frequency signals to determine the Doppler shift of said scattered light beam which is reprsentative of said electrophoretic mobility and to determine the frequency distribution of said scattered light beam which is representative of said diffusion coefficient.
Claim 4
Independent Claim
129 words
A method of determining the electrophoretic mobility and diffusion coefficient of a macromolecular polymer in solution, which method comprises the following steps: establishing an electric field across said solution to move said macromolecules through said solution in a direction parallel with said electric field at a velocity proportional to said electrophoretic mobility; applying a light beam comprising monochromatic electromagnetic radiation incident on said macromolecules; detecting said light beam scattered by said macromolecules; heterodyning said detected scattered light beam with said incident light beam to produce beat frequency signals; and analyzing said beat frequency signals to determine the Doppler shift of said scattered light beam which is reprsentative of said electrophoretic mobility and to determine the frequency distribution of said scattered light beam which is representative of said diffusion coefficient.
Claim 5
Dependent Claim
31 words
The method of claim 1 including alternately enabling and disabling said electric field during the determination of said electrophoretic mobility and said diffusion coefficient to reduce heat build-up in the solution.
Claim 6
Dependent Claim
29 words
The method of claim 2 including delaying said analyzing for a predetermined time interval after said electric field is enabled to allow said macromolecules to reach a steady state.