Separation Of Nitrotoluene Isomeric Compound By High Pressure Liquid Chromatography

n-nitrotoluene is main material of synthetical spice. o-nitrotoluene is intermediate of synthetical medicine and dyestuff.They are both extensively used.The separation of them is studied all the while.Traditional methods include freezing point and gas chromatography,But the effect of separation is not so good. In this thesis,the separation of n-nitrotoluene and o-nitrotoluene is studied comprehensively by high-pressure liquid chromatography.The optimal conditions of separation are confirmed.By comparation we select C18 bonded-phase chromatography column and mixture of methanol and water as mobile phase.We choose methanol as solvent of specimen by comparing water, mixture of methanol and water and methanol.We set up methanol:water respectively as 20:80; 30:70; 40:60; 50:50; 60:40; 70:30:80:20(V/V)with the other conditions invariable.The result show that when methanol:water=80:20 base-line separation is obtained with a 2.44 resolution.On the other hand velocity of flow is investigate ed .we set up respectively velocity of flow as 0.8,0.9,1.0,1.1,1.2ml/min.The result are with velocity of flow increasing retention time minish but resolution diminish too. The best chromatogryphy conditions are methanol:water=80:20; detected wavelength is 278nm; velocity of flow is 1.0ml/min; room temperature; chromatogryphy column: COSMOSIL 5C18-AR-Ⅱ(6.0mm×250mm) In addition,the method is validated by recoveries experiment.The results show this method is reproducible and sensitive enough for separation of n-nitrotoluene and o-nitrotoluene.