Anodization in HO(CH₂CH₂O)_nH (1a, n=2; 1b, n=3; 1c, n=4) as an initial derivatization tool for preparing glassy carbon (GC) electrodes covalently modified with amino compounds was explored. As an amino compound to be immobilized, 4-amino-2,2,6,6-tetramethylpiperidinyl-1-oxyl (4-amino-TEMPO) was selected. When GC electrodes anodized at 2.0 V vs. Ag wire coated with AgCl in 1 containing RCH₂CH₂SO₃Na (2a, R=H; 2b, R=OH) were treated with a N,N-dimethylformamide (DMF) or CH₂Cl₂ solution of 4-amino-TEMPO and 1,3-dicyclohexylcarbodiimide (DCC), TEMPO-modified GC electrodes were afforded. Coverage (Γ_TEMPO) of the electrode surfaces by TEMPO was estimated by cyclic voltammetry in CH₃CN containing NaClO₄. A TEMPO-modified GC electrode with the best Γ_TEMPO (1.36×10^-10 mol/cm²) was obtained by anodization in 1b containing 2a at the expense of 3.0 C followed by amidization in DMF for 7 d. On cyclic voltammetry, the TEMPO-modified GC electrode showed good and stable electrocatalytic ability for oxidation of allyl alcohol in the presence of 2,6-lutidine.