2.3. Preparation of reducing mini column packed
with copperized cadmi um
A copperized cadmium column was prepared as
follows: powdered cadmium (Wako Pure Chem.,
60-80 mesh) was copperized according to the
procedure of the Japanese Industrial Standard (JIS
K-0 10 1 - 1991), and the copperized cadmium
obtained was packed in a silica tubing (0.53 mm i.d.
x 10cm).
2.4. Procedure for the collection of NO2 from air
and the measurement of NO/ and NO3-
Air samples were pumped through separatory
funnels (260 ml) for 2 min in order to sufficiently
exchange air in the separatory funnels for the
sample. Then, 2ml of an absorption solution was
added into each separatory funnel, and the
separatory funnels were shaken vigorously for 4
min. After standing for 1 min, nitrate andlor nitrite
ion in the absorbing solutions were measured by the
proposed pFIA.