Elution or solubilization of radioactive material

The elution method is rather laborious. The slices of the gel are eluted with, e.g., 

1% SDS, preferably directly into the scintillation vials. Then the vials are shaken with 10 ml of Instagel emulsifier (scintillant Packard) for 3-5 h at 37°C and counted. Efficiency is 7% for and 33% for C. Alternatively the radioactive materials can be solubilized and thus liberated from the electrophoretic support. This can be materialized by, e.g., Bio-Solv BBS-3 (Beckman Instruments, acidic surfactant). The scintillation solution used is composed of 4 g PPO, 0.2 g POPOP, 170 ml Bio-Solv-BBS 3, 60 ml of water, and 770 ml of toluene [242]. Another solubilizer that can be applied is NCS (Nuclear Chicago Solubilizer) with this solubilizer the polyacrylamide or polyacrylamide-agarose gel slices have to be incubated at 65°C for 2 h. Tritiated ribonucleic acid fractions can be solubilized with 10% piperidine at 60°C. Gel slices are incubated in the scintillating vials with the solubilizer for several hours, allowed to dry, dissolved in distilled water (the gel actually swells at this stage), covered with water miscible toluene scintillation fluid and counted. 

Solubilization of proteins for radioactivity counting can be also effected by non-specific proteases or by chaotropic agents (guanidinium chloride). In the latter case gel slices are incubated with 1 ml of 6 M guanidinium hydrochloride at 90°C for 12 h. Then, 33% Triton X scintillation fluid is added and samples are counted. Efficiency is 12% for tritiated compounds. 

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