Gravimetric deposition of microliter drops with radiometric confirmation.

A manual microliter gravimetric dispensing technique is demonstrated using a micropipettor modified for use with removeable microcapillaries. Liquid scintillation sources were prepared from a well-characterized Am reference solution, providing a radiometric check of dispensed masses. Further experiments confirmed controlled dispensing of drops onto gold foils with losses ≤0.34(4) % of the total drop activity. A detailed measurement equation for the weighing technique, including the corrections for evaporation, is presented with a full accounting of associated uncertainties.