Application of chelate forming resin amberlite XAD-2-vanillinthiosemicarbazone to the separation and preconcentration of copper(II), zinc(II) and lead(II)

acide chlorhydrique acide nitrique acido nitrico agua potable analytical methods atomic absorption spectrometry cinc cobre copper cuivre drinking water eau potable heavy metals hydrochloric acid lead metales pesados nitric acid oligoelementos ph plomb plomo resinas resine resins separating separation sorption technique analytique trace elements zinc