On-Column Derivatization-RHPLC Determination of Trace Amounts of Lead in Extracts of Tribulus Terrestris

In the method reported in this paper,microwave assisted sample digestion with HNO3 and HClO4 was adopted.Bis salicylaldehyde-o-phenyldiamine was used as derivatizing agent for Pb2+ ion.DiamonsilTM C18 column (4.6 mm×150 mm,5 μm) was used as the stationary phase in the chromatographic separation.Methanol,water and bis-salicylaldehyde-o-phenyldiamine were mixed in the ratio of 64.5 to 34.0 to 1.5 by volume and the mixed solution was used as the mobile phase passing through the column at a flow-rate of 1.1 mL·min-1,which was found to be proper for the on-line derivatization and for elution of the derivative.It was found that 30 ℃ was the suitable temperature for the column,and for UV-detection made at the wavelength of 275 nm.Linear relationship between values of peak area and amount of lead was obtained in the range 0.10-0.63 ng.Average of recovery was found to be 99.5%,with value of RSD′s (n=7) to be 1.8%.