Hello,
The most important thing when you collect your rain samples is to
prevent from evaporation which will preferentially removes the
lighter isotope (16O).
 A sampler should be placed about 1.5 or 2 m above ground. You can
use  a plastic graduated cylinder with a plastic funnel on the top to
collect the  rainwater. You should add few ml of mineral oil to
prevent (minimize) evaporation which will cause fractionation. When
storing your sample it is better to use a poly-seal glass bottles,
sealed with paraffin and best if you keep it referegrated till you
analyze them.
Hope this helps.

Million

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Million Hailemichael (Ph.D.)
4905 34th Ave. S
Minneapolis, MN 55417
phone: (612)722-5787

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