HAIR ANALYSIS FOR NICOTINE AND COTININE - EVALUATION OF EXTRACTION PROCEDURES, HAIR TREATMENTS, AND DEVELOPMENT OF REFERENCE MATERIAL

Analysis of nicotine and cotinine in human hair can provide informatio n on nicotine intake and exposure to environmental tobacco smoke over a long period of time. Nonetheless, to better assess the usefulness of hair analysis to determine smoking habits or exposures, all procedure s have to be standardized. Various solvents were tested as washing sol vents to eliminate external contamination from nicotine. Dichlorometha ne was found effective when used for two washes prior to the extractio n. Basic and acid digestion of hair followed by solid phase extraction with Extrelut-3 glass column using dichroromethane:isopropyl alcohol (9:1) as eluting mixture both gave good recoveries of nicotine and cot inine, when compared with extractions reported in the literature. The extraction method was free from substances, which could interfere in t he chromatographic analysis. Furthermore, the addition of methanolic H Cl to the eluting mixture prevented the loss of nicotine during the ev aporation step before chromatography. Chromatography was performed usi ng a reversed-phase column and a U.V. detection at 254 nm. Furthermore , hair treatments (dyes, permanent wave, hydrogen peroxide) caused a m ajor decrease in the nicotine content in hair, and a smaller effect on cotinine levels. However, the effect of various treatments was not re producible. Several attempts to produce reference materials were carri ed out. Nicotine and cotinine standard solutions at different concentr ations were added to blank hair soaked in dimethylsulfoxide, methanol and water. (C) 1997 Elsevier Science Ireland Ltd.