Magnesium stock solution (Merck, Titrisol 1.09949)
which included 1.000±0.002 g magnesium as MgCl2 in 6%
HCl was used for preparing the standard solutions.
Nitric
acid (Riedel-de Haen 07006) was used in the digestion of
the samples.
The extraction solvents used were chloroform
(A certain amount of olive (0.2–0.3 g) was weighed, 5ml
of concentrated HNO3 was added and was heated under controlled
pressure.
Samples were left in the furnace at 150 ◦C
and 13.61 atm maximum pressure for 25 min.
After digestion
of the samples, the mixture was diluted to 50 ml.
Magnesium
determinations were made after adding strontium
by FAAS. Olive oil (0.5 g) samples were weighed in PTFE
vessels and 10 ml of concentrated HNO3 was added.
Two microwave digestion programs were applied step by
step.
System temperature was increased gradually to
160 ◦C over 40 min and controlled pressure (maximum
13.61 atm).
The digested sample volume was diluted to