# US 5,348,636 A · Processes for the preparation and separation of macromolecules > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,348,636 A - Document ID: US5348636A - Status: Granted - Kind: A - Application number: 08/148,239 - Filed: 1993-11-08 - Granted: 1994-09-20 - Earliest claimed: 1989-04-24 - Assignees: Xerox Corporation - Inventors: Gary Slater; Jaan Noolandi; Chantal Turmel - Web page: https://patentgrep.com/patent/US5348636A ## CPC - B01D 57/02: by electrophoresis (treatment of water, waste water, sewage or sludge by electrophoresis C02F1/469; electrophoretic production of compounds or non-metals C25B7/00; investigating or analysing materials by using electrophoresis G01N27/26) - G01N 27/44773: {Multi-stage electrophoresis, e.g. two-dimensional electrophoresis} - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract A process for the electrophoretic separation of charged macromolecules includes applying to the macromolecules a periodic sequence of pulses. Each period comprises a multiplicity of electric field pulses of negative and positive polarities. The negative polarity pulses are applied for a longer total time duration than the positive polarity pulses within each period. The average intensity of the negative polarity pulses is less than the average intensity of the positive polarity pulses. ## Claims ### Claim 1 A process for the electrophoretic separation of charged macromolecules which comprises applying to said macromolecules a periodic sequence of pulses with each period comprising a multiplicity of electric field pulses of negative polarities and positive polarities, wherein the negative polarity pulses are applied for a longer total time duration than the positive polarity pulses within each period, and the average intensity of the negative polarity pulses is less than the average intensity of the positive polarity pulses. ### Claim 2 (depends on 1) A process in accordance with claim 1 wherein substantially all of the negative polarity pulses are of lower intensities than the positive polarity pulses. ### Claim 3 (depends on 1) A process in accordance with claim 1 wherein the separation is accomplished in an electrophoresis device. ### Claim 4 (depends on 1) A process in accordance with claim 1 wherein the macromolecules are contained in a gel. ### Claim 5 (depends on 4) A process in accordance with claim 4 wherein the gel is Agarose NA. ### Claim 6 (depends on 1) A process in accordance with claim 1 wherein the macromolecules are comprised of DNA. ### Claim 7 (depends on 1) A process in accordance with claim 1 wherein the electric field pulses are applied for a total of from about 1 to about 10 days. ### Claim 8 (depends on 1) A process in accordance with claim 1 wherein the electric field pulses are applied for a total of about 3 days. ### Claim 9 (depends on 1) A process in accordance with claim 1 wherein the positive polarity pulses last from about 0.1 to about 10,000 seconds for each pulse. ### Claim 10 (depends on 1) A process in accordance with claim 1 wherein the positive polarity voltages pulses within a period are applied with a value of more than 0 to about a positive 10 volts per centimeter for each pulse. ### Claim 11 (depends on 1) A process in accordance with claim 1 wherein the negative polarity pulses last from about 0.1 to about 10,000 seconds for each pulse. ### Claim 12 (depends on 1) A process in accordance with claim 1 wherein the negative polarity pulses within a period are applied with a value of less than 0 to about a negative 10 volts per centimeter for each pulse. ### Claim 13 (depends on 1) A process in accordance with claim 1 wherein each period comprises time intervals of zero-field intensity. ### Claim 14 (depends on 1) A process in accordance with claim 1 wherein at least one of the negative polarity pulses is of a lower value than any of the positive polarity pulses. ### Claim 15 (depends on 1) A process in accordance with claim 1 wherein a majority of the negative polarity pulses are of lower intensities than the positive polarity pulses. ### Claim 16 (depends on 1) A process in accordance with claim 1 wherein an average field intensity is computed as being the sum of the products of the pulse intensities multiplied by the pulse durations, divided by the sum of the pulse durations, and wherein nonzero intensity pulses are excluded. ### Claim 17 A process for the electrophoretic separation of charged macromolecules which comprises applying to said macromolecules a periodic sequence of pulses with each period comprising a multiplicity of electric field pulses of negative polarities and positive polarities wherein the negative polarity pulses are applied for a longer time duration than the positive polarity pulses, and the average intensity of the negative polarity pulses is less than the average intensity of the positive polarity pulses and wherein zero integrated field electrophoresis is applied whereby the net integrated value of the electric field pulses during one complete period is zero. ### Claim 18 A process for the electrophoretic separation of charged macromolecules which comprises applying to said macromolecules a periodic sequence of pulses with each period comprising a multiplicity of electric field pulses of negative polarities and positive polarities wherein the negative polarity pulses are applied for a longer time duration than the positive polarity pulses, and the average intensity of the negative polarity pulses is less than the average intensity of the positive polarity pulses and wherein field pulse durations, and field intensities are changed during the process. ### Claim 19 A process for the separation of charged macromolecules which comprises repeatedly applying to said macromolecules contained in an electrophoresis device a periodic sequence of pulses with each period comprising pulses of a first electric field and pulses of a second electric field, and wherein the fields are of opposite polarity and along a single dimension; the second field is of lower intensity than the first field; and the second field is applied for a longer duration than the first field for each period. ### Claim 20 (depends on 19) A process in accordance with claim 19 wherein the first electric field is applied for about 0.1 to about 10,000 seconds for each period. ### Claim 21 (depends on 19) A process in accordance with claim 19 wherein the second electric field is applied for about 0.1 to about 10,000 seconds for each period. ### Claim 22 (depends on 19) A process in accordance with claim 19 wherein the first electric field is of a positive polarity. ### Claim 23 (depends on 19) A process in accordance with claim 19 wherein the first electric field is of an intensity of from about 0.5 to about 10 volts/centimeter. ### Claim 24 (depends on 19) A process in accordance with claim 19 wherein the second electric field is of a negative polarity. ### Claim 25 (depends on 19) A process in accordance with claim 19 wherein the second electric field is of an intensity of from about 0.2 to about 5 volts/centimeter. ### Claim 26 A process for the separation of charged macromolecules which comprises repeatedly applying to said macromolecules contained in an electrophoresis device a periodic sequence of pulses with each period comprising pulses of a first electric field and pulses of a second electric field and wherein the fields are of opposite polarity and along a single dimension; the second field is of lower intensity than the first field; and the second field is applied for a longer duration than the first field for each period and wherein zero integrated field electrophoresis is applied whereby the net integrated value of the first and second electric fields during one complete period is about zero. ### Claim 27 (depends on 26) A process in accordance with claim 26 wherein the macromolecules are contained in a gel. ### Claim 28 (depends on 27) A process in accordance with claim 27 wherein the gel is Agarose NA. ### Claim 29 (depends on 28) A process in accordance with claim 28 wherein the concentration of agarose in the gel is between about 0.2 and about 2 percent.