ADSORPTIVE STRIPPING VOLTAMMETRY FOR DETERMINATION OF ALUMINUM IN PLANT-SAMPLES

Aluminium content in samples of commercial tea leaves, coffee beans an d in the tea brewed from analysed tea leaves was determined, as descri bed previously, by adsorptive stripping voltammetry with calmagite. Be fore each determination the samples were mineralized using a dry metho d. Electrochemical determinations were carried out in 0.04 mol l-1 ace tate buffer (pH = 4.2) in the presence of 10(-5) mol l-1 calmagite sol ution. After heating of the samples (10 min at 90-degrees-C) which all owed aluminium-calmagite complex formation, adsorptive preconcentratio n was carried out for less than 1 min at -0.24 V. Cathodic curves were recorded in the range from -0.24 V to -0.8 V. In some of the samples the interfering Fe(III) ions were removed by reduction with hydroxylam ine hydrochloride. The accuracy of the method was tested using Citrus Leaves SRM 1572 as the reference material.