DEVELOPMENT AND CHARACTERIZATION OF AN ELISA FOR COTININE IN BIOLOGICAL-FLUIDS

Cotinine is a major metabolite of nicotine and serves as an important biomarker of tobacco smoke exposure. To monitor exposure to tobacco sm oke or nicotine, a sensitive enzyme-linked immunosorbent asay (ELISA) for cotinine was developed. The test had an 1-50 pf betweem 0.5 and 1. 0 ng/ml for cotinine and about 500-fold for nicotine. Few matrix effec ts were not detectable in human saliva, although relatively small matr ix effects (1-50 for cotinine, 2.8 ng/ml were observed in human serum and urine. The test accurately measured the levels of cotinine in NIST standards in freeze-dried human urine derivative material (r =.9999) indicating its reliability for measurement of cotinine. The test readi ly detected low levels (5-500 ng/ml of cotinine in human saliva and se rum samples. Also, the levels of cotinine in plasma and urine samples from smoke-exposed mice and rats could be rapidly analyzed for cotinin e. This ELISA is therefore a sensitive and accurate test for the deter mination of cotinine in plasma, serum, saliva, and urine samples from humans and animals, and can be successfully used for monitoring and qu antifying exposure to tobacco smoke or nicotine.