Loss of ATP in micromolar amounts after perchloric acid treatment

Treatment of fluid samples containing known amounts of ATP with 6.0 N perchloric acid (PCA) results in a total loss of 65-71% when the initial concentrations of ATP ranged between 0.5 to 50 muM. Half of this loss was attributed to desensitization of firefly extract (luciferin-luciferase reaction) while the remaining loss was presumably due to adsorption of ATP to perchlorate precipitate upon neutralization. Similar treatment of solutions with higher initial concentrations (100-1000 muM) resulted in apparent total losses averaging 22%. These losses were due solely to desensitization of firefly extract by neutralized PCA. Both the adsorption and desensitization phenomena must be taken into account when the ATP content is measured from tissue extracts and fluid samples subjected to this procedure.