Carbonyl compounds exist in air, water, food, biological fluids and tissues, as well as nonbiological materials. Many methods have been developed to detect carbonyl compounds in the air, including numerous derivatization reagents to make carbonyl compounds more stable, multiple extraction methods, as well as multiple detection methods. These methods can be costly and time consuming, and also make use of toxic solvents. We sought a quick and inexpensive method to detect and quantify total carbonyls in air samples, specifically diesel exhaust samples, as well as extra cellular media in biological samples. We derivatized standard carbonyl compounds with 2,4-dinitrophenyl hydrazine(DNPH); heptane was more efficient than pentane or hexane in extraction of the derivatives and leaves excess DNPH almost entirely in the aqueous phase. To test the usefulness of this technique carbonyls from diesel exhaust were collected on Sep-Pak DNPH-Silica cartridges, eluted, extracted with heptane, and analyzed by spectrophotometry and HPLC/UV/MS. Linear regression analysis indicated a strong correlation (0.9821) between the UV absorbance (365nm) of each sample and the total mass of carbonyl derivatives separated by HPLC and determined by MS. The usefulness of this technique was also tested on a biological sample. BEAS- 2B cells were exposed to differing concentrations of residual oil fly ash (ROFA). UV absorbance increased with increasing ROFA concentrations, suggesting that carbonyl groups (products of lipid peroxidation) increased with increasing concentrations of ROFA. These results indicate that a quick and inexpensive method to detect and quantify total carbonyls in air samples, specifically diesel exhaust samples, as well as extracellular media in biological samples, may be achieved through the extraction of carbonyl derivatives with heptane and subsequent detection by spectrophotometry. In the future, there is potential to use this method to detect carbonyls in food and water samples.