Metal-organic　frameworks　(MOFs)　have　great　potential　for　applications　in　chromatography　due　to　their　highly　tailorable　porous　structures　and　unique　properties.　In　this　work,　the　stable　MOF　UiO-66　was　evaluated　as　both　a　normal-phase　(NP-)　and　a　reverse-phase　(RP-)　stationary　phase　in　the　high　performance　liquid　chromatography　(HPLC)　to　separate　substituted　benzenes　(SBs)　and　polycyclic　aromatic　hydrocarbons　(PAHs).　It　was　found　that　the　mobile　phase　composition　has　a　significant　effect　on　the　HPLC　separation.　Baseline　RP-HPLC　separations　of　xylene　isomers;　naphthalene　and　anthracene;　naphthalene　and　chrysene;　and　naphthalene,　fluorene,　and　chrysene　were　achieved　using　MeOH/H2O　ratios　of　80:20,　75:25,　85:15,　and　75:25,　respectively,　on　the　UiO-66　column.　Similarly,　baseline　NP-HPLC　separations　of　xylene　isomers　and　ethylbenzene;　ethylbenzene,　styrene,　o-xylene,　and　m-xylene;　and　several　PAHs　were　also　obtained　on　the　UiO-66　column　with　different　mobile　phase　compositions.　The　relative　standard　deviations　(RSDs)　of　retention　time,　peak　height,　peak　area,　and　half　peak　width　for　five　replicate　separations　of　the　tested　analytes　were　within　the　ranges　0.2-0.4%,　0.2-1.6%,　0.7-3.9%,　0.4-1.1%,　respectively.　We　also　evaluated　other　critical　HPLC　parameters,　including　injected　sample　mass,　column　temperature,　and　the　thermodynamic　characters　of　both　the　RP-HPLC　and　the　NP-HPLC　separation　processes.　It　was　confirmed　that　the　separation　of　SBs　on　a　UiO-66　column　was　an　exothermic　process,　controlled　by　both　enthalpy　change　(Delta　H)　and　entropy　change　(Delta　S).　The　reverse　shape　selectivity,　size　selectivity,　stacking　effect,　and　electrostatic　force　played　vital　roles　in　the　separations　of　these　analytes.　To　the　best　of　our　knowledge,　this　method　is　one　of　the　very　few　examples　of　using　MOFs　as　the　stationary　phase　in　both　NP-HPLC　and　RP-HPLC.　MOF-based　stationary　phases　may　thus　be　applied　in　the　separations　and　analyses　of　SBs　and　PAHs　in　environmental　samples.　(C)　2014　Elsevier　B.V.　All　rights　reserved.