A 13.0 mL of standard copper (5.0 ng/mL) aqueous solution was
taken into centrifugal polyethylene tube with addition of 0.5 mL
each of ascorbic acid, buffer solution, 1.0% NaCl, 0.6 103 M
DPT and total volume of the solution was 15.0 mL. Then, 0.5 mL
absolute ethanol (dispersing solvent) and 0.2 mL of chloroform
containing PBITU (extraction solvent) were injected into the aqueous
phase and shaken for few minutes. The cloudy solution was
formed that consisted of finely droplets of extraction solvent dispersed
in the sample solution. Finally, the centrifugation (REMI,
R4C Centrifuge Machine) was carried out at 754.6g for 2 min,
and the organic phase at the top of the aqueous phase was carefully
withdrawn using a microsyringe and placed into a tube. The
obtained volume of the sample volume was found to be small to
analyse in FAAS, so it was diluted to 400 lL with ethanol. This solution
was directly nebulised into the flame without use of any particular
injection system.