A method of preventing fouling of digital microfluidic electrodes while processing fluids containing proteins, comprising: mixing or dissolving a compound in the fluid; wherein the compound is ethylenediamine tetrakis(ethoxylate-block-propoxylate) tetrol with 16 ethylene oxide repeat units and 18 propylene oxide repeat units; or wherein the compound is wherein R is x ethylene oxide repeat units and y propylene oxide repeat units, wherein x is in a range from 8 to 24, and wherein y is in a range from 8 to 30; or wherein the compound is wherein n is an integer of at least 2, wherein R is x ethylene oxide repeat units and y propylene oxide repeat units, and wherein x is an integer in a range from about 4 to about 32, and y is an integer in a range from about 2 to about 36, and wherein X and Y are any one of the following groups or wherein the compound is wherein R is x ethylene oxide repeat units and y propylene oxide repeat units, and wherein x is an integer in a range from about 4 to about 32, and y is an integer in a range from about 2 to about 36; or wherein the compound is wherein R is x ethylene oxide repeat units and y propylene oxide repeat units, and wherein x is an integer in a range from about 4 to about 32, and y is an integer in a range from about 2 to about 36; or wherein the compound is wherein n is an integer of at least 2, wherein R is x ethylene oxide repeat units and y propylene oxide repeat units, wherein x is an integer in a range from about 4 to about 32, and y is an integer in a range from about 2 to about 36, and wherein X is any one of or wherein the compound is wherein R is x ethylene oxide repeat units and y propylene oxide repeat units, wherein x is an integer in a range from about 4 to about 32, and y is an integer in a range from about 2 to about 36, and wherein X, Y and Z are any one of or wherein the compound is wherein R is x ethylene oxide repeat units and y propylene oxide repeat units, wherein x is an integer in a range from about 4 to about 32, and y is an integer in a range from about 2 to about 36. wherein the compound is ethylenediamine tetrakis(ethoxylate-block-propoxylate) tetrol with 16 ethylene oxide repeat units and 18 propylene oxide repeat units; or wherein the compound is wherein R is x ethylene oxide repeat units and y propylene oxide repeat units, wherein x is in a range from 8 to 24, and wherein y is in a range from 8 to 30; or wherein the compound is wherein n is an integer of at least 2, wherein R is x ethylene oxide repeat units and y propylene oxide repeat units, and wherein x is an integer in a range from about 4 to about 32, and y is an integer in a range from about 2 to about 36, and wherein X and Y are any one of the following groups or wherein the compound is wherein R is x ethylene oxide repeat units and y propylene oxide repeat units, and wherein x is an integer in a range from about 4 to about 32, and y is an integer in a range from about 2 to about 36; or wherein the compound is wherein R is x ethylene oxide repeat units and y propylene oxide repeat units, and wherein x is an integer in a range from about 4 to about 32, and y is an integer in a range from about 2 to about 36; or wherein the compound is wherein n is an integer of at least 2, wherein R is x ethylene oxide repeat units and y propylene oxide repeat units, wherein x is an integer in a range from about 4 to about 32, and y is an integer in a range from about 2 to about 36, and wherein X is any one of or wherein the compound is wherein R is x ethylene oxide repeat units and y propylene oxide repeat units, wherein x is an integer in a range from about 4 to about 32, and y is an integer in a range from about 2 to about 36, and wherein X, Y and Z are any one of or wherein the compound is wherein R is x ethylene oxide repeat units and y propylene oxide repeat units, wherein x is an integer in a range from about 4 to about 32, and y is an integer in a range from about 2 to about 36.