Measurements were conducted to assess the MiniVol PM2.5 sampler performance for various particle preseparator configurations including flat and cup impaction stages. Laboratory measurements were conducted to determine the impactor collection efficiency as a function of paricle size. Impactor cut points - the aerodynamic particle diameter exhibiting 50% collection efficiency - were 2.5 um (+- 10%) for the flat stage and 3.0 um for the cup stage. Collection efficiency curves for cascade (tandem) impactor configurations (PM10 followed by PM2.5) generally agreed with the single stage results. In all cases the collection efficiency curves exhibited the classical sigmoidal shape, albeit less steep than required for PM2.5 Federal Reference Method (FRM) samplers. Field data was collected at urban sites in St. louis using MiniVol samplers collocated wiht a PM2.5 FRM sampler to quantify the MiniVol sampler precision and accuracy. Collocated sampler precision was 6% and 10% for MiniVol cascade impactors with flat PM2.5 stages and cup PM2.5 stages, respectively (N=31). Both of these MiniVol configurations were deemed statistically equivalent to the FRM when the reported ambient mass concentrations were corrected for field blank values (N=15).