Keywords: ورادزیل; Stable free radical; Fluorescence quencher; Spin-probe; Verdazyl; Water soluble; MFJAEQVGAQNQCY-UTLUCORTSA-N; HMDJUFYVUMHPOB-VPOLOUISSA-N; MFJAEQVGAQNQCY-KXUCPTDWSA-N; QWUBHXLIGIQXHM-USYJJFMDSA-N; MFJAEQVGAQNQCY-BBBLOLIVSA-N; HMDJUFYVUMHPOB-ZNSHCXBVSA-N;