A method for preparing phosphine-based selective transition metal binding particles, said method comprising at least a step of: - reacting macroporous particles comprising at least one "NH" reactive function reacted with at least one molar equivalent of R-P(CH 2 OH) 2, in which R is selected from the group consisting of: - -CH 2 OH; - linear, branched, or cyclic (C 1- C 25)alkyl groups, optionally substituted with one or more of the following substituents: -C OH, -C H, -C R 1, -C OR 1, -NR 1 R 2, -C SR 1, in which R 1 and R 2 are, independently of each other, selected in the group consisting of linear, branched, and cyclic (C 1 -C 10)alkyl groups; - C 5 -C 6 aryl groups; and - a benzyl group, optionally substituted with one or more substituents selected from the group consisting of linear, branched, or cyclic (C 1- C 25)alkyl or (C 1 -C 3)alkoxy groups, -C OH, -C H, -C R 1, -C OR 1, -NR 1 R 2, NO 2, and -C SR 1; with a nucleophile reactive agent of formula NHR a R b, wherein R a and R b are, independently of each other, selected from the group consisting of: - H; - linear, branched, or cyclic (C 1 -C 25)alkyl groups, optionally substituted with at least one moiety selected from the group consisting of -NH 2, -C OH, -OH, -C NH 2, -SR c in which R c is H or CH 3, a saturated, unsaturated or aromatic hydrocarbon-based 5 to 9 membered-mono- or bi-cycle comprising optionally at least one heteroatom chosen from N, O or S; - -C R d or C R d with R d being NH 2 or a linear, branched or cyclic C 1 -C 25 alkyl optionally substituted with at least one -NH 2 moiety; - with x ranging from 2 to 70; - with y ranging from 2 to 40 and x+z ranging from 1 to 6; - with x being 2 or 3; - with R being H or Et, n being 0 or 1 and x+y+z ranging from 5 to 90, said method comprising the sequential modification of a) phosphine particles obtained from the reaction of amine-functionalized type particles reacted with phosphine-based compounds R-P(CH 2 OH) 2 with b) amine-based compounds. - reacting macroporous particles comprising at least one "NH" reactive function reacted with at least one molar equivalent of R-P(CH 2 OH) 2, in which R is selected from the group consisting of: - -CH 2 OH; - linear, branched, or cyclic (C 1- C 25)alkyl groups, optionally substituted with one or more of the following substituents: -C OH, -C H, -C R 1, -C OR 1, -NR 1 R 2, -C SR 1, in which R 1 and R 2 are, independently of each other, selected in the group consisting of linear, branched, and cyclic (C 1 -C 10)alkyl groups; - C 5 -C 6 aryl groups; and - a benzyl group, optionally substituted with one or more substituents selected from the group consisting of linear, branched, or cyclic (C 1- C 25)alkyl or (C 1 -C 3)alkoxy groups, -C OH, -C H, -C R 1, -C OR 1, -NR 1 R 2, NO 2, and -C SR 1; with a nucleophile reactive agent of formula NHR a R b, wherein R a and R b are, independently of each other, selected from the group consisting of: - H; - linear, branched, or cyclic (C 1 -C 25)alkyl groups, optionally substituted with at least one moiety selected from the group consisting of -NH 2, -C OH, -OH, -C NH 2, -SR c in which R c is H or CH 3, a saturated, unsaturated or aromatic hydrocarbon-based 5 to 9 membered-mono- or bi-cycle comprising optionally at least one heteroatom chosen from N, O or S; - -C R d or C R d with R d being NH 2 or a linear, branched or cyclic C 1 -C 25 alkyl optionally substituted with at least one -NH 2 moiety; - with x ranging from 2 to 70; - with y ranging from 2 to 40 and x+z ranging from 1 to 6; - with x being 2 or 3; - with R being H or Et, n being 0 or 1 and x+y+z ranging from 5 to 90, - H; - linear, branched, or cyclic (C 1 -C 25)alkyl groups, optionally substituted with at least one moiety selected from the group consisting of -NH 2, -C OH, -OH, -C NH 2, -SR c in which R c is H or CH 3, a saturated, unsaturated or aromatic hydrocarbon-based 5 to 9 membered-mono- or bi-cycle comprising optionally at least one heteroatom chosen from N, O or S; - -C R d or C R d with R d being NH 2 or a linear, branched or cyclic C 1 -C 25 alkyl optionally substituted with at least one -NH 2 moiety; - with x ranging from 2 to 70; - with y ranging from 2 to 40 and x+z ranging from 1 to 6; - with x being 2 or 3; - with R being H or Et, n being 0 or 1 and x+y+z ranging from 5 to 90,