Sources of error in VOC determination via EPA Method 24

Forty-five paint samples having volatile organic content (VOCs) ranging from 7 to 562 g/L were prepared and tested for VOC according to EPA Method 24. In addition, all individual raw materials utilized in preparing the paints were also tested for their VOCs. There were significant differences between claimed and measured VOCs for both raw materials and finished paints. The measurement error for VOC of finished paints was eight percent. This error increased exponentially as the VOC declined below about 250 g/L, reaching about 200% at VOCs below 50 g/L. The range of error also increased exponentially below about 250 g/L, reaching 1000% below 50 g/L. The major sources of VOC error in all cases were in the water and nonvolatile determinations.