radioactive assays - (Jan/10/2011 )

hi

Iam using C14 labelled to assay the upatake of Adenosine.I inject 23 nl of water as the control and 23 ng of RNA for the test.The problem that Iam facing is I get variable values for my control after I count in the scintialltion counter. Soemtimes it is around 150CPM and the other time it is 1000-3000CPM. Could any one help me to find out this varaibility. Thanks in advance.

jaya

need more information (eg-protocol).

is the rna in water? if not then add the same buffer to the control reaction.

is the water sterile? if not then you may be introducing contamination.

hoe do you handle the assay after introducing the rna/water?