All reagent used the presented work

All reagent used the presented work were of analytical reagent grade unless otherwise stated. Double deionized water was used for all dilutions. HNO3 and H2O2 were of suprapure quality. All the plastic and glassware were cleaned by soaking in dilute HNO3 and were rinsed with distilled water prior to use. The standard solution of analytes used for calibration were produced by diluting a stock solution of 1000mg of the given element supplied by Sigma and Aldrich, USA.