title: Determination of transition metal ions in tobacco as their 2-(2-quinolinylazo)-5-dimethylaminophenol derivatives using reversed-phase liquid chromatography with UV-VIS detection.
abstract: This paper reports the utilization of solid-phase extraction and the reversed-phase high-performance liquid chromatography for the determination of six important transition metal ions: iron, cobalt, nickel, copper, zinc and manganese in tobacco with 2-(2-quinolinylazo)-5-dimethylaminophenol (QADMAP) as chelating reagent. Iron, cobalt, nickel, copper, zinc and manganese ions react with QADMAP to form colored chelates in the medium of acetic acid-sodium acetate buffer solution (pH 4.0). These chelates can be enriched by solid-phase extraction with Waters Sep-Pak-C18 cartridge, and eluted the retained chelates from cartridge with tetrahydrofuran. The chelates were separated on a Waters Nova-Pak-C18 column (150x3.9 mm, 5 microm) by gradient elution with methanol (containing 0.5% of acetic acid) and 0.05 mol/l pH 4.0 acetic acid-sodium acetate buffer solution as mobile phase at a flow-rate of 0.5 ml/min. The detection limits of iron, cobalt, nickel, copper, zinc and manganese are 10, 12, 8, 13, 17 and 22 ng/l, respectively. This method had been applied to the determination of iron, cobalt, nickel, copper, zinc and manganese in tobacco with good results.
mesh_terms: D001372:Aza Compounds / Q000737:chemistry*; D002138:Calibration; D002412:Cations; D002614:Chelating Agents / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D008670:Metals / Q000032:analysis*; D011804:Quinolines / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D014026:Nicotiana / Q000737:chemistry*
chemical_list: C472811:2-(2-quinolinylazo)-5-dimethylaminophenol; D001372:Aza Compounds; D002412:Cations; D002614:Chelating Agents; D008670:Metals; D011804:Quinolines