Laser photobleaching of human serum: application to fluorescence immunoassays

Background fluorescence from serum chromophores is substantially reduced by a laser photobleaching method. Human and bovine serum samples were illuminated with 337-nm light from a pulsed N2 laser for a short period of time. The serum emission in the region of 440 to 550 nm was reduced by an order of magnitude with no evident damage to serum proteins as judged by the unchanged activity of alkaline phosphatase and aspartate aminotransferase.