p-Nitrophenyl　organophosphates　(OPs)　including　paraoxon,　parathion　and　methyl　parathion,　etc,　are　highly　poisonous　OPs,　for　which　sensitive　and　rapid　detection　method　is　most　needed.　In　this　work,　an　ultrasensitive　electrochemical　sensor　for　the　determination　of　p-nitrophenyl　OPs　was　developed　based　on　ordered　mesoporous　carbons　(OMCs)　modified　glassy　carbon　electrode　(GCE)　(OMCs/GCE).　The　electrochemical　behavior　and　reaction　mechanism　of　p-nitrophenyl　OPs　at　OMCs/GCE　was　elaborated　by　taking　paraoxon　as　an　example.　Experimental　conditions　such　as　buffer　pH,　preconcentration　potential　and　time　were　optimized.　By　using　differential　pulse　voltammetry,　the　current　response　of　the　sensor　at　-0.085　V　was　linear　with　concentration　within　0.01-1.00　mu　M　and　1.00-20　mu　M　paraoxon.　Similar　linear　ranges　of　0.015-0.5　mu　M　and　0.5-10　mu　M　were　found　for　parathion,　and　0.01-0.5　mu　M　and　0.5-10　mu　M　for　methyl　parathion.　The　low　limits　of　detection　were　evaluated　to　be　1.9　nM　for　paraoxon,　3.4　nM　for　parathion　and　2.1　nM　for　methyl　parathion　(S/N　=　3).　Common　interfering　species　had　no　interference　to　the　detection　of　p-nitrophenyl　OPs.　The　sensor　can　be　applicable　to　real　samples　measurement.　Therefore,　a　simple,　sensitive,　reproducible　and　cost-effective　electrochemical　sensor　was　proposed　for　the　fast　direct　determination　of　trace　p-nitrophenyl　OPs　at　low　potential　without　deoxygenization.　(C)　2014　Elsevier　B.　V.　All　rights　reserved.