Measurement of Radioactivity
11
decreasing the quenching caused by the presence of water in the samples
(naphthalene ).
Among the most common of such mixed secondary solvents and the scintillation cocktails based on them can be mentioned:
Toluene-methanol (ethanol or methoxyethanol) solvents. These secondary
solvents are useful for counting aqueous samples with minimal water contents, less than O.S ml per sample. In this case, the radioactive sample is inserted
first into the vial, then the alcohol is added to the sample until it makes a
homogenous solution. Then the toluene scintillation cocktail is added to the
mixture.
Toluene SOOml + cellosolve SOOml + Sg PPO + 0.1 g POPOP.
The same, but toluene is replaced by dioxane:
670ml toluene + 330ml Triton-X-100 + Sg PPO + 0.1 g POPOP (Triton X-lOO
is the alkyl-aryl polyether alcohol).
The same, but toluene is replaced by dioxane:
11 toluene + 300ml soluene + lOOg naphtalene + 19 PPO + 0.6g POPOP,
100ml methanol + 20ml ethylene glycol + 900ml dioxane + 4g PPO + 2g
PO POP (Bray's cocktail).
These cocktails take up to 4 ml of water per 10 ml. The cocktails with Triton
X-lOO form jelly-like counting samples. Various companies sell special gellifying cocktails like Instagel, Aquasol, and Malincrod Hand Fluor. The latter can
take up to 6 ml of water per 10 ml.
To count suspensions which cannot be dissolved in solvents, gelling substances are added to the cocktails. These substances gel the counting sample,
keeping the suspended matter evenly distributed in the column of the scintillation liquid, thus increasing counting efficiency. For this purpose aluminum
sterate, thixcin (a castor oil derivative), silicagel (Cab-o-sil) or Triton-X-lOO
are used. The standard gellifying scintillation cocktail Instagel is supplied by
Packard.
The solubilization of animal and plant tissues or other labeled organic
materials for the preparation of homogenous samples in liquid scintillation
counting is usually carried out with alkaline compounds such as sodium
hydroxide, organic quaternary ammonium bases (like ethanolamine, phenylamine, hyamine), detergent Triton-X-100, acids such as perchloric or nitric
acids, or their mixtures (Hansen and Bush 1967; Crooks and Johnson 1977;
Peng 1981). Hyamine and its derivative solutions in toluene, or methanol, such
as NCS and Soluene-lOO, are commercially available from Packard, Beckman,
or Amersham. Sodium hydroxide used as a solubilizer of animal tissue is
0.S-1.0 N solution in methanol. The treatment of animal or plant tissue samples
for scintillation counting is usually accomplished directly in 20-ml glass
11
decreasing the quenching caused by the presence of water in the samples
(naphthalene ).
Among the most common of such mixed secondary solvents and the scintillation cocktails based on them can be mentioned:
Toluene-methanol (ethanol or methoxyethanol) solvents. These secondary
solvents are useful for counting aqueous samples with minimal water contents, less than O.S ml per sample. In this case, the radioactive sample is inserted
first into the vial, then the alcohol is added to the sample until it makes a
homogenous solution. Then the toluene scintillation cocktail is added to the
mixture.
Toluene SOOml + cellosolve SOOml + Sg PPO + 0.1 g POPOP.
The same, but toluene is replaced by dioxane:
670ml toluene + 330ml Triton-X-100 + Sg PPO + 0.1 g POPOP (Triton X-lOO
is the alkyl-aryl polyether alcohol).
The same, but toluene is replaced by dioxane:
11 toluene + 300ml soluene + lOOg naphtalene + 19 PPO + 0.6g POPOP,
100ml methanol + 20ml ethylene glycol + 900ml dioxane + 4g PPO + 2g
PO POP (Bray's cocktail).
These cocktails take up to 4 ml of water per 10 ml. The cocktails with Triton
X-lOO form jelly-like counting samples. Various companies sell special gellifying cocktails like Instagel, Aquasol, and Malincrod Hand Fluor. The latter can
take up to 6 ml of water per 10 ml.
To count suspensions which cannot be dissolved in solvents, gelling substances are added to the cocktails. These substances gel the counting sample,
keeping the suspended matter evenly distributed in the column of the scintillation liquid, thus increasing counting efficiency. For this purpose aluminum
sterate, thixcin (a castor oil derivative), silicagel (Cab-o-sil) or Triton-X-lOO
are used. The standard gellifying scintillation cocktail Instagel is supplied by
Packard.
The solubilization of animal and plant tissues or other labeled organic
materials for the preparation of homogenous samples in liquid scintillation
counting is usually carried out with alkaline compounds such as sodium
hydroxide, organic quaternary ammonium bases (like ethanolamine, phenylamine, hyamine), detergent Triton-X-100, acids such as perchloric or nitric
acids, or their mixtures (Hansen and Bush 1967; Crooks and Johnson 1977;
Peng 1981). Hyamine and its derivative solutions in toluene, or methanol, such
as NCS and Soluene-lOO, are commercially available from Packard, Beckman,
or Amersham. Sodium hydroxide used as a solubilizer of animal tissue is
0.S-1.0 N solution in methanol. The treatment of animal or plant tissue samples
for scintillation counting is usually accomplished directly in 20-ml glass