empirically,
was
Following
1.16.
analysis by gamma spectroscopy,
the ashed
samples were dissolved in a known volume of 1N HNO3.
Stron-
tium-90 was determined on an aliquot by the method of Kawabata
and Held (1958),
in which a combination of nitric acid precipi-
tation and ion exchange procedures is used.
Calcium was determined by the permanganate titration of
oxalic acid and was confirmed by flame spectrophotometry, with
the internal standard technique of
Chow and Thompson
(1955).
Potassium was determined by flame spectrophotometry at 766 mu
wave length and independently confirmed with estimation of
potassium by titration of the cobaltinitrite with potassium
permanganate
(Hibbard and Stout,
at 589 mit wave length.
In
1933).
Sodium was determined
making these determinations,
slit width was kept at a minimum to
blue-sensitive filter was used
eliminate
the
interference;
and the sensitivity set as high
as possible consistent with the reproducibility.
The
flame
spectrophotometer was a Beckman DU equipped with a vacuum tube
power supply and an oxy-hydrogen flame.
The
standardization
procedure and general function of the system has been described
by Chakravarti and Joyner (1960).
In determining magnesium,
was dissolved in 0.1N HCl and
an aliquot of the ashed sample
the solution
passed through
a