Different concentrations of tin between syrup
and fruit were observed. Samples of canned mandarins
and pineapple were used for this experiment.
The content of can was separated into syrup and
solid parts. Some amount of tin was determined
in both. 52–64 mg/kg of tin for syrup samples and
65–133 mg/kg of tin were observed for solid part.
The concentration of tin was higher in solid part
than syrup. As syrup of pineapple contained very
small parts was filtered and amount of tin was
determined in pure syrup and small part from the
filter. The amount of tin in syrup was 48 mg/kg,
but in the filtered parts 728 mg/kg. However, these
small parts composed less than 1% of total content
of can. These results might be accounted for by
the adsorption capacity of tin on the surface.
Relationship between the concentration and
time period after opening was studied. For this
experiment were used samples of canned mandarins,
pineapple and peaches. The content of
can was separated into two parts. In the first part
was immediately determined concentration of tin
in syrup and fruit. The second part of can was
stored at 6°C. The concentration of tin in syrup
after 1, 3, 6 and 24 h was determined by duration
of experiment. Amount of tin in both parts was
determined after 48 hours. All results are summarised
in Figure 1. The corrosion of the tinplate
surface was accelerated by air and the amount of
dissolved tin was significantly increasing in syrup
as well as fruit when cans were opened and stored
for two days at 6°C.