Carrier ampholytes of high pH range

In a method for separating components of a sample according to isoelectric point, said method comprising imposing an electric potential across an electrophoresis medium loaded with said sample, said electrophoresis medium having suspended therein a plurality of carrier ampholytes distributed throughout said medium according to isoelectric point to form a pH gradient therein, the improvement in which said carrier ampholytes are compounds having the formula

• X(CH2)m—Yn(CH2)m-Z
• in which:
• m is 1 to6;
• n is 1 to 20;
• when n is 2 or greater, either all Y is the same or Y differs among different (—(CH2)m—Y—) groups;
• and
• X, Y, and Z are independently selected from the group consisting of amine groups and guanidine groups such that at least one group represented by X, Y, and Z is a guanidine group;
• and
• at least one amine group represented by X, Y, or Z is substituted with at least one carboxylate substituent having the formula
• in which:
• R1 is a member selected from the group consisting of H, C1-4 alkyl, C(O)OH, C(O)O—(C1-4 alkyl), (C1-4 alkylene)-C(O)OH, and (C1-4 alkylene)-C(O)O—(C1-4 alkyl);
• R2 is a member selected from the group consisting of H, C1-4 alkyl, C(O)OH, C(O)O—(C1-4 alkyl), (C1-4 alkylene)-C(O)OH, and (C1-4 alkylene)-C(O)O—(C1-4 alkyl);
• and
• R3 is a member selected from the group consisting of H and C1-4 alkyl.