1,2-Dimethoxybenzene-13C6; 2-Methoxyanisole-13C6; Catechol Dimethyl Ether-13C6; Methylguaiacol-13C6; NSC 16934-13C6; O,O-Dimethylcatechol-13C6; Pyrocatechol Dimethyl Ether-13C6; Veratrol-13C6; Veratrole-13C6; o-Dimethoxybenzene-13C6; o-Hydroquinone Dimethyl Ether-13C6; o-Methoxyanisole-13C6;,Veratrole Stable Isotopes