Determination of Cobalt, Nickel and Copper in Flowers, Leaves, Stem and Roots of Plants Using Ultrasonic Slurry Sampling Electrothermal Atomic Absorption Spectrometry

Abstract

An ultrasonic slurry sampling electrothermal atomic absorption spectrometric method was developed and used for the determination of Co, Ni and Cu in the four plant species Helichrysum candolleanum , Peristrophe decorticans , Blepharis diverspinia and Tephrosia burchelli . The plants were sampled in a copper–nickel mining site in Botswana, Africa. For each plant species, flowers, leaves, stem and roots were analysed. The concentration range of the elements was 0.2–10 µg g ^-1 for Co, 20–400 µg g ^-1 for Ni and 30–600 µg g ^-1 for Cu. The method was validated by comparing the results from slurry sampling with those from the analysis of decomposed samples. The two methods gave comparable precision and accuracy. The relative standard deviations were in the range 1–14 and 1–20% for slurry sampling and decomposed materials, respectively. Analysis of certified plant reference materials also confirmed the accuracy of the method; no significant difference from the certified values was found when the slurry sampling technique was used.