Microanalysis of ''biometallic'' compounds using nuclear and atomic activation

A novel method for the characterization of metal containing biological compounds has been developed which utilizes both nuclear activation [e.g., 12C(3He, α)11C] and atomic activations (X-ray emission) induced by 8 MeV 3He bombardment. Detection limits for carbon (approximately 1 μg), oxygen (approximately 1 μg), and metals (1 to 10 ng for elements between P and Zn) were obtained under routine experimental conditions. The metal stoichiometry of six different compounds (alkaline phosphatase, amylase, carbonic anhydrase, diamine oxidase, myoglobin, vitamin B12) were determined with typical relative precisions of +-25% for a 40 μg sample. A comparison of these ratios with carbon and metal measurements obtained by other methods showed a relative accuracy of 1 to 20%. (author)