So far, very few precise and accurate methods
for the determination of copper in tea leaves have
been suggested. For example, differential pulse polarography
preceded by solvent extraction of Cu(II)
chelates in rather toxic chloroform was used for the
determination of copper in tea specimens [16]. A
copper(II) membrane coated graphite electrode based
on Schiff’s base and showing a very short lifetime
was applied for the determination of copper
in a sample of Iranian black tea [17]. Recently, the
FAAS determination of trace copper in tea samples
after preconcentration with 1-nitroso-2-naphtol-3,6-
disulfonic acid on Ambersorb 572 has also been suggested
[6].