Abstract: A method for detecting an analyte of interest present in a mixture at an ultralow concentration includes selecting a radioactive derivatizing agent comprising a multiphoton-emitting radioisotope moiety and a moiety reactive with the analyte of interest, the radioisotope moeity being bound to the derivatizing agent by a bond that is stable under the conditions employed in the other steps of the method, derivatizing the analyte of interest with the derivatizing agent, separating the analyte of interest from other components of the mixture by chromatography, and detecting the analyte of interest using multiphoton detection. The derivatizing step may be performed before or after fractionation. A radiophore for multiphoton emission enhanced chromatography has a first moeity bound to a multiphoton-emitting radioisotope, and a second moiety that is reactive with a functional group of an analyte of interest.

Abstract: A method for detecting an analyte of interest present in a mixture at an ultralow concentration includes selecting a radioactive derivatizing agent comprising a multiphoton-emitting radioisotope moiety and a moiety reactive with the analyte of interest, the radioisotope moeity being bound to the derivatizing agent by a bond that is stable under the conditions employed in the other steps of the method, derivatizing the analyte of interest with the derivatizing agent, separating the analyte of interest from other components of the mixture by chromatography, and detecting the analyte of interest using multiphoton detection. The derivatizing step may be performed before or after fractionation. A radiophore for multiphoton emission enhanced chromatography has a first moeity bound to a multiphoton-emitting radioisotope, and a second moiety that is reactive with a functional group of an analyte of interest.

Abstract: A cryogenic detector comprises an array formed from a plurality of spherical grains made of type I superconducting material arranged in a preselected pattern and each having a preselected size (generally less than about 100 microns in diameter). Also disclosed is a method of making such an array by depositing a film of selected thickness of type I superconducting material on a substrate, etching the film to provide an array formed by a plurality of discrete pixels, melting the pixels under conditions whereby the pixels are transformed into substantially spherical shape, and cooling to freeze the molten pixels into substantially spherical grains.