A compound comprising a water-soluble, non-peptidic, and non-nucleotidic polymer backbone having at least one terminus covalently bonded to a structure of formula: or a salt thereof, Wherein: A is the point of covalent bonding to the terminus of the polymer backbone; E is O; K is selected from the group consisting of: alkylene, alkyleneoxyalkylene, and oligomeric alkyleneoxyalkylene; G is selected from the group consisting of: hydrogen, alkoxy, and a hydrophobic separation handle which is a trityl, a substituted trityl, a pixyl or a substituted pixyl; Z 1 is O and Z 2 is NH; L is selected from the group consisting of: a divalent radical of a nucleoside, alkylene, alkyleneoxyalkylene, oligomeric alkyleneoxyalkylene, and unsubstituted and substituted arylene; M is a protected group that when deprotected is reactive with a biologically active molecule, a group reactive with a biologically active molecule, or is a detectable functional group that physically or chemically interacts with its environment to produce a signal or product that is detected by analytical and/or imaging methods, in particular visible, UV-, IR-, NIR-light, X- Ray, and NMR-based imaging methods, enzymatic assays, and UV-, IR-, NMR-, X-ray-, and mass spectrometry-based analytics; R is absent or selected from the group consisting of: hydrogen, a protecting group, a hydrophobic separation handle which is a trityl, a substituted trityl, a pixyl or a substituted pixyl, or an activating group; R 1 is absent or a hydrophobic separation handle which is a trityl, a substituted trityl, a pixyl or a substituted pixyl, wherein when M is a protected group that when deprotected is reactive with a biologically active molecule, then R is a protecting group or a hydrophobic separation handle, which is a trityl, a substituted trytil, a pixyl, or a substituted pixyl; wherein when M is a group reactive with a biologically active molecule, R is absent, hydrogen, or an activating group; and wherein when M is a detectable functional group, R is absent or hydrogen; and wherein at least one of R, R 1, and G is a hydrophobic separation handle. A is the point of covalent bonding to the terminus of the polymer backbone; E is O; K is selected from the group consisting of: alkylene, alkyleneoxyalkylene, and oligomeric alkyleneoxyalkylene; G is selected from the group consisting of: hydrogen, alkoxy, and a hydrophobic separation handle which is a trityl, a substituted trityl, a pixyl or a substituted pixyl; Z 1 is O and Z 2 is NH; L is selected from the group consisting of: a divalent radical of a nucleoside, alkylene, alkyleneoxyalkylene, oligomeric alkyleneoxyalkylene, and unsubstituted and substituted arylene; M is a protected group that when deprotected is reactive with a biologically active molecule, a group reactive with a biologically active molecule, or is a detectable functional group that physically or chemically interacts with its environment to produce a signal or product that is detected by analytical and/or imaging methods, in particular visible, UV-, IR-, NIR-light, X- Ray, and NMR-based imaging methods, enzymatic assays, and UV-, IR-, NMR-, X-ray-, and mass spectrometry-based analytics; R is absent or selected from the group consisting of: hydrogen, a protecting group, a hydrophobic separation handle which is a trityl, a substituted trityl, a pixyl or a substituted pixyl, or an activating group; R 1 is absent or a hydrophobic separation handle which is a trityl, a substituted trityl, a pixyl or a substituted pixyl,