Abstract: The present invention includes a method and apparatus for measuring the transport of analytes from living, biological cells through a cell barrier, which includes, but is not limited to, steps of providing the living, biological cells loaded with analytes, unloading at least a portion of said analytes from the cells through ion channels, removing unloaded analyte remaining in the cells, and measuring the analytes using x-ray fluorescence, specifically wherein the measurement uses an energy dispersive x-ray fluorescence spectrometer equipped with a microfocus x-ray tube. These steps may be repeated so that multiple measurements can be obtained over a period of time.

Abstract: Methods, apparatus and compositions are described for the measurement of metal and/or metalloid elements, including selenium in samples. More specifically, the present disclosure provides a sensor and/or array of sensors to measure metal and/or metalloid analytes, e.g., sensor and/or array of sensors having a chelator molecule, the chelator molecule including a peptide.

Abstract: The present invention relates, in part, to methods of using X-ray fluorescence (XRF) spectrometry for analyzing (e.g., measuring) the binding of a soluble target to an insoluble material.

Abstract: The present invention includes a method for analyzing reactions. The method includes the steps of providing a solution of at least one acceptor chemical and at least one donor chemical. The donor chemical is capable of donating a chemical moiety to the acceptor chemical. The solution further includes at least one controller chemical that affects the reaction between the donor chemical and the acceptor chemical. The solution is then incubated so that a portion of the acceptor chemical reacts with the donor chemical to form an acceptor product. Unreacted donor chemical is separated from the acceptor product. The acceptor product or the donor chemical is then measured using X-ray fluorescence. Another aspect of the present invention includes a method for analyzing protein function. The method includes the steps of providing a solution of at least one acceptor chemical and at least one donor chemical. The donor chemical is capable of donating a chemical moiety to the acceptor chemical.

Abstract: The present invention is a method to quantify biomarkers. The method uses an X-ray florescence spectrometer to perform an X-ray fluorescence analysis on the sample to obtain spectral features derived from the biomarker; and quantifying the X-ray fluorescence signal of the biomarker.

Abstract: X-ray fluorescence (XRF) spectrometry has been used for detecting binding events and measuring binding selectivities between chemicals and receptors. XRF may also be used for estimating the therapeutic index of a chemical. For estimating the binding selectivities of a chemical versus chemical analogs, for measuring post translational modification of proteins, and for drug manufacturing.

Abstract: The present invention includes an apparatus for preparing samples for measurement by x-ray fluorescence spectrometry. The apparatus comprises a plate having one or more holes passing through the plate. The holes are covered by a film on one side of the plate. The holes are less than 500 micrometers across in one dimension where the film covers the holes. The film is translucent to x-rays. The present invention also includes an apparatus for preparing samples for measurement by x-ray fluorescence spectrometry. The apparatus comprises a plate having one or more holes passing through the plate. The holes are covered on one side of the plate by a detachable cover forming a water-tight seal against the plate. The cover is substantially free of the elements osmium, yttrium, iridium, phosphorus, zirconium, platinum, gold, niobium, mercury, thallium, molybdenum, sulfur, lead, bismuth, technetium, ruthenium, chlorine, rhodium, palladium, argon, silver, and thorium.