Synthesis of amidinothioureido-silica geland its application to flame atomic absorption spectrometric determiantion of silver,gold and palladium with on-line preconcentration and separation

摘要

A simple and highly selective flow injection(FI) on-line preconcentration and separation flame atomci absorption spectrometric (FAAS0 method was developed for the determinations of trace amounts of silver,gold and palladium.The selective preconcentration of the noble metals metals was achieved in a wide range of sample acidity (0.1-6MHNO_3 or HCl) on a microcolumn packed with amidinothioureido-silica gel (ATuSG).The analytes retained on the column were effectively eluted with 5.0% thiourea solution.The analytical procedure was optimized for sample acidity,elution,interferences,flow rate of sampling and eluting,and concentration of sample.Common co-existing cations and anions did not interfere with the preconcentration and determination of the three metals.At a sample loading flow rate of 4.5 ml min~(-1) with 60s preconcentration,detection limits of 1.1 ng ml~(-1) Ag,13 ng ml~(-1) Au and 17 ng ml~(-1) Pd were obtained.The precisions were 1.2% for Ag,1.2% for Au and 1.7% for Pd,respectively.The detection limits can be further improved by increasing sample volume.The analytical results obtained by the proposed method for a number of standardreference amterials were in good agreement with the certified values.