Determining Radioactivity Counts in Solutions by Liquid Scintillation Counting
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Determining Radioactivity Counts in Solutions by Liquid Scintillation Counting
Contributor:
The Laboratory of Michael Chamberlin at the University of California, Berkeley
Overview
These solutions are easy-to-make liquid scintillants for liquid scintillation counting. In addition to the recipes for making the liquid scintillants, this protocol describes two general methods for determining the radioactivity in organic and aqueous solutions.
Procedure
A. To Count Non-Aqueous Samples in A Scintillation Counter (such as dried filters)
1. Place samples in scintillation vials.
2. Add an appropriate volume of Toluene-PPO-POPOP (see Hint #2).
3. Place in scintillation counter and count.
B. To Count Aqueous Samples in A Scintillation Counter
1. Add an appropriate volume of Bray's Solution (see Hint #2).
2. Add an aliquot of liquid samples (see Hint #3).
3. Mix samples to disperse them in Scintillation Fluid.
4. Place in scintillation counter and count.
Solutions
Bray's Solution
Dilute to 1 liter with p-Dioxon. (CAUTION! See Hint #1)
100 ml Methanol
4 g PPO (2, 5-diphenyloxazole)
60 g Naphthalene (CAUTION! See Hint #1)
20 ml Ethylene glycol
0.1 g POPOP (2-p-phenylenebis 5-phenyloxazole) 
Toluene-PPO-POPOP
4 g PPO (2,5-diphenyloxazole) (CAUTION! See Hint #1)
Dilute to 1 liter with Toluene (CAUTION! See Hint #1)
0.1 g POPOP (2-p-phenylenebis 5-phenyloxazole) (CAUTION! See Hint #1)
BioReagents and Chemicals
p-Dioxon
Ethylene Glycol
Naphthalene
Methanol
Toluene
2-p-Phenylenebis 5-phenyloxazole
2,5-Diphenyloxazole
Protocol Hints
1. CAUTION! This substance is a biohazard. Consult this agent's MSDS for proper handling instructions.
2. Consult the instructions for your scintillation counter to determine the volume of Scintillation Fluid required to obtain accurate readings.
3. A 10 ml aliquot of Bray's Solution will accept up to 3 ml of aqueous solution without phase separation.
Citation and/or Web Resources
1. Bray AG. Anal. Biochem. 1960;1:279
