A method of purifying quaternary onium salts comprising the step of contacting a composition comprising an onium salt and a first concentration of ionic impurities with an ion exchange resin, said resin being provided in an ion exchange column or in a fixed or fluid ion exchange bed, to produce a composition comprising a quaternary onium salt and a second concentration of ionic impurities, wherein said second concentration of ionic impurities is less than said first concentration of ionic impurities, wherein said quaternary onium salt is provided to the method as a liquid onium salt or in the form of a solution of an onium salt in a solvent; and wherein said quaternary onium salt has the formula selected from the group consisting of: and wherein A is nitrogen; n and m are independently 0 or 1; Any is a single, double or aromatic bond; R 10, R 15 R 24 and R 25 are independently a substituted or unsubstituted C 1 -C 12 alkyl, substituted or unsubstituted fluoroalkyl, a member of a five or six member saturated, unsaturated, or aromatic cyclic or heterocyclic structure, or a member of a polycyclic structure; R 5 - R 9, R 11 - R 14, and R 16 - R 23 are independently H, F, C1, substituted or unsubstituted C 1 - C 12 alkyl, substituted or unsubstituted fluoroalkyl, a member of a five or six member saturated, unsaturated, or aromatic cyclic or heterocyclic structure, or a member of a polycyclic structure; R 1 - R 4 are independently C 1 - C 12 alkyl, a substituted or un-substituted C 1 - C 12 alkyl, a substituted or un-substituted fluoroalkyl, a member of a 5- or 6-member saturated, unsaturated or aromatic cyclic or heterocyclic, or a member of a polycyclic structure; D 10 - D 13 are independently carbon, nitrogen, sulfur, or oxygen provided that at least two of D 10 - D 13 are carbon; when a D ring member is carbon, n and m are 1 for their corresponding R groups; when a D ring member is oxygen or sulfur, n and m are 0 for their corresponding R groups; D 1 - D 9 are independently carbon, nitrogen, sulfur, or oxygen provided that at least two of D 6 - D 9 are carbon; at least three of D 1 - D 5 are carbon; when a D ring member is carbon, n is 1 for its corresponding R group; when a D ring member is nitrogen, oxygen, or sulfur, n is 0 for its corresponding R group; the bond between any two adjacent D members is single, double, or aromatic; the bond between A and either of its two adjacent D members is single, double or aromatic provided that A is tetravalently bonded; and Z is selected from the group consisting of: BF 4 -; [BF x (C y F 2y+1-z H z) 4x] n - in which the ligands (C y F 2y+1-z H z) may be identical or different, 1≤x≤5, 3≤y≤8 and 0≤z≤y+1; CF 3 SO 3 -; SbF 6 -; N(SO 2 CF 3) 2 -; C 4 H 3 O 4 -; and ClO 4 -, and wherein said ionic impurity is selected from the group consisting of fluoride ion, chloride ion, bromide ion, iodide ion, free acid, and combinations of these. A is nitrogen; n and m are independently 0 or 1; Any is a single, double or aromatic bond; R 10, R 15 R 24 and R 25 are independently a substituted or unsubstituted C 1 -C 12 alkyl, substituted or unsubstituted fluoroalkyl, a member of a five or six member saturated, unsaturated, or aromatic cyclic or heterocyclic structure, or a member of a polycyclic structure; R 5 - R 9, R 11 - R 14, and R 16 - R 23 are independently H, F, C1, substituted or unsubstituted C 1 - C 12 alkyl, substituted or unsubstituted fluoroalkyl, a member of a five or six member saturated, unsaturated, or aromatic cyclic or heterocyclic structure, or a member of a polycyclic structure; R 1 - R 4 are independently C 1 - C 12 alkyl, a substituted or un-substituted C 1 - C 12 alkyl, a substituted or un-substituted fluoroalkyl, a member of a 5- or 6-member saturated, unsaturated or aromatic cyclic or heterocyclic, or a member of a polycyclic structure; D 10 - D 13 are independently carbon, nitrogen, sulfur, or oxygen provided that at least two of D 10 - D 13 are carbon; when a D ring member is carbon, n and m are 1 for their corresponding R groups; when a D ring member is oxygen or sulfur, n and m are 0 for their corresponding R groups; D 1 - D 9 are independently carbon, nitrogen, sulfur, or oxygen provided that at least two of D 6 - D 9 are carbon; at least three of D 1 - D 5 are carbon; when a D ring member is carbon, n is 1 for its corresponding R group; when a D ring member is nitrogen, oxygen, or sulfur, n is 0 for its corresponding R group; the bond between any two adjacent D members is single, double, or aromatic; the bond between A and either of its two adjacent D members is single, double or aromatic provided that A is tetravalently bonded; and Z is selected from the group consisting of: BF 4 -; [BF x (C y F 2y+1-z H z) 4x] n - in which the ligands (C y F 2y+1-z H z) may be identical or different, 1≤x≤5, 3≤y≤8 and 0≤z≤y+1; CF 3 SO 3 -; SbF 6 -; N(SO 2 CF 3) 2 -; C 4 H 3 O 4 -; and ClO 4 -, and wherein said ionic impurity is selected from the group consisting of fluoride ion, chloride ion, bromide ion, iodide ion, free acid, and combinations of these. BF 4 -; [BF x (C y F 2y+1-z H z) 4x] n - in which the ligands (C y F 2y+1-z H z) may be identical or different, 1≤x≤5, 3≤y≤8 and 0≤z≤y+1; CF 3 SO 3 -; SbF 6 -; N(SO 2 CF 3) 2 -; C 4 H 3 O 4 -; and ClO 4 -, and