Method for analysis using X-ray fluorescence

1. A method for measuring a response to a neurodegenerative disorder therapy, comprising

obtaining a sample which has been exposed to a therapy and a sample which has not been exposed to a therapy, the samples each comprising a biomarker comprising one or more chemicals that are related to a neurodegenerative disorder, wherein the samples are prepared for X-ray analysis by exposure to a solution;

using an X-ray fluorescence spectrometer to perform an X-ray fluorescence analysis on the samples to obtain spectral features derived from the biomarker; and

quantifying the X-ray fluorescence signal of the biomarker and comparing the signal of the sample which has been exposed to the therapy and the sample which has not been exposed to the therapy;

wherein the X-ray fluorescence spectrometer irradiates the sample with polychromatic X-rays.

2. The method of claim 1 , wherein the solution is selected from a pH buffer, a redox buffer, a preservative, a fixative, and a sterilizing solution.

3. The method of claim 1 , wherein the solution is free of at least one chemical element having an atomic number greater than eight, where the element is present in the sample.

4. The method of claim 1 , wherein the solution is free of at least one of the chemicals or functional groups selected from the group consisting of dimethylsulfoxide, thiols, sulfate anion, sulfonate anions, chloride anion, bromide anion, fluoride anion, iodide anion, perchlorate anion, phosphate anion, and phosphonate anions.

5. The method of claim 1 , wherein the solution comprises one or more chemicals selected from the group consisting of amine, imine, nitrate anion, nitrite anion, ammonium cation, acetate anion, carboxylate anion, conjugate bases of carboxylic acids, carbonate anion, formalin, formaldehyde, ethanol, 2-propanol, and iminium cation.

6. The method of claim 1 , wherein the samples are fractionated to provide sample fractions.

7. The method of claim 6 , wherein the fractionating is performed using a technique selected from centrifugation, mechanical separation, chemical separation, enzymatic separation, condensation, chromatographic methods, gel electrophoresis, isoelectric focusing, 2-dimensional electrophoresis, precipitation, density gradient fractionation and immobilization of analytes to solid formats.

8. The method of claim 7 , wherein the solid format is selected from beads, membranes, arrays, microarrays, spin plate, or well plates.

9. The method of claim 1 , wherein at least one sample is disposed on or in a sample holder, and the sample holder comprises at least one chemical element which is not present in the sample.

10. The method of claim 1 , wherein the samples are biological samples.

11. The method of claim 10 , wherein the biological samples are selected from tissue samples, biological fluids, biopsy samples, cells, dried biospecimens, fresh biospecimens, immortalized cell lines, membranes, plasma, primary cell cultures, and subcellular fractionates.

12. The method of claim 1 , wherein the fluorescence analysis comprises multiple X-ray fluorescence analyses.

13. The method of claim 12 , wherein the multiple fluorescence analyses are obtained by disposing one or more of the samples at two or more different angles relative to an excitation source.

14. The method of claim 1 , wherein the X-ray fluorescence spectrometer comprises a rhodium X-ray tube excitation source.