Abstract: The present invention comprises a method for measuring the transport of analytes through a cell. The method comprises the steps of providing one or more cells containing at least 10 picograms of an analyte within a volume defined by the area of an x-ray excitation beam and a depth of live times the 1/e attenuation, depth for at least one characteristic x-ray signal of the analyte as attenuated by water. The method further comprises the step of removing at least a of portion of the analyte from the cells. The method also comprises the steps of exciting at least a portion of the analyte that has been removed from the cells with an x-ray beam; and using an x-ray detector to measure x-ray fluorescence.

Abstract: An apparatus for preparing samples for measurement by x-ray fluorescence spectrometry. A plate has 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.

Abstract: The present invention includes a method and apparatus for measuring the transport of analytes through a cell barrier.

Abstract: The present invention includes a method and apparatus for measuring the removal of analyte from a cell. One or more cells are provided, comprising at least 10 picograms of an analyte within a volume defined by the area of an x-ray excitation beam and a depth of a depth of five times the 1/e attenuation depth for at least one characteristic x-ray signal of the analyte as attenuated by water. At least a of portion of the analyte is removed from the cells; and the analyte is measured using x-ray fluorescence.

Abstract: An apparatus for preparing samples for measurement by x-ray fluorescence spectrometry. A plate has 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.

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.

Abstract: The present invention includes a method and apparatus for measuring the transport of analytes through a cell barrier.

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 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.