Drug development and manufacturing

A method for detecting a binding event of at least one chemical having at least one heavy element to at least one receptor, comprising:

• exposing the at least one bead-supported receptor to X-ray radiation by means of a micro-X-ray fluorescence spectrometer prior to exposing the at least one receptor to the at least one chemical to be tested for binding to the at least one receptor;
• measuring the X-ray fluorescence signal intensity of the at least one receptor;
• combining the at least one bead-supported receptor and the at least one chemical then allowing a receptor-chemical complex to form;
• wherein the at least one chemical comprises at least one heavy element selected from the group consisting of P, Cl, F, S, and Br;
• removing any at least one chemical that is not part of the receptor-chemical complex;
• exposing the receptor-chemical complex to X-ray radiation from an X-ray excitation source;
• measuring the X-ray fluorescence signal intensity of the at least one heavy element in the receptor-chemical complex;
• and
• evaluating the receptor-chemical complex X-ray fluorescence signal intensity such that when the heavy element is present in both the at least one chemical and the at least one receptor, an assessed difference in the X-ray signal intensities of the receptor-chemical complex and the at least one receptor signifies that a binding event has occurred between the at least one chemical and the at least one receptor;
• and when the heavy element is only present in the at least one chemical but not the at least one receptor, the X-ray signal intensity of the receptor-chemical complex signifies that a binding event has occurred between the at least one chemical and the at least one receptor.