A device that measures radioactivity flowing through a sample chamber using new technologies has been devised. The goal of this proposal is to complete development of the instrument, and to field test it. Such a device will lower the cost of counting radioactive samples. Because of its increased sensitivity, lower levels of radioactivity can be used, decreasing laboratory personnel and reducing environmental pollution. Since HPLC and GLC are pervasive in all areas of biomedical research, the device will have broad application. Examples of current uses of HPLC are in separation of inositol phosphates as second messengers, and radioactive toxins, including potential carcinogens.