Interest of a Simple Mobile Phase Containing Diethylamine-Acetic Acid for HPLC Assay of Nicotine and Cotinine

Abstract We have developed a simple mobile phase containing a diethylamine/acetic acid mixture free of salts and ion-pairing compounds for the assay of nicotine and cotinine in biological media by means of high-performance liquid chromatography. The best composition was found to be methanol/acetonitrile/acetic acid/water (230/20/2/748 v/v) adjusted to pH 5.00 or 6.40 with diethylamine. The results were excellent when compared with those obtained from