# US 10,871,583 B2 · Mercury-free concentration standard for x-ray analysis

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- Number: US 10,871,583 B2
- Document ID: US10871583B2
- Status: Granted
- Kind: B2
- Application number: 16/387,596
- Filed: 2019-04-18
- Published: 2019-10-24
- Granted: 2020-12-22
- Earliest claimed: 2018-04-24
- Assignees: University of Louisiana at Lafayette
- Applicants: University of Louisiana at Lafayette
- Inventors: Harry James Whitlow
- Web page: https://patentgrep.com/patent/US10871583B2

## CPC

- G01T 7/005: {calibration techniques (stabilization of spectrometer G01T1/40)}
- G01N 23/207: Diffractometry using detectors, e.g. using a probe in a central position and one or more displaceable detectors in circumferential positions
- G01N 23/223: by irradiating the sample with X-rays or gamma-rays and by measuring X-ray fluorescence
- G01T: MEASUREMENT OF NUCLEAR OR X-RADIATION (radiation analysis of materials, mass spectrometry G01N23/00; tubes for determining the presence, intensity, density or energy of radiation or particles H01J47/00)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

Instruments used to analyze the chemical composition of samples must be calibrated to provide accurate results. Typically, standards are prepared that contain a known amount of the intended analyte to facilitate calibration of the analytical instrument. Various environmental issues are associated with use of mercury containing materials as standards for calibration of analytical instruments. Mercury and gold have very similar characteristic X-ray energies. Standards containing gold nanoparticles have been found to be a good surrogate for mercury in X-ray spectroscopy.

## Claims

### Claim 1

A standard without the toxicity of mercury used to calibrate an apparatus used to analyze a sample for mercury content which comprises:
(a) gold nanoparticles;
(b) a matrix powder.

### Claim 2 (depends on 1)

The standard of claim 1 wherein the apparatus is a spectrophotometer.

### Claim 3 (depends on 1)

The standard of claim 1 wherein the matrix powder is copper.

### Claim 4 (depends on 1)

The standard of claim 1 wherein the matrix powder is tin.

### Claim 5 (depends on 1)

The standard of claim 1 wherein the matrix powder is silver.

### Claim 6 (depends on 1)

The standard of claim 1 where the elemental matrix powder forms a solid incorporating the gold nanoparticles on compression.

### Claim 7 (depends on 1)

The standard of claim 1 where the matrix powder is comprised of more than one element.

### Claim 8 (depends on 1)

The standard of claim 1 wherein the matrix powder is bound together by a precisely defined quantity of binder.

### Claim 9

A method for determining the concentration of mercury in a sample comprising:
(a) calibrating an X-ray spectrometer using a standard,
(b) analyzing the sample using the calibrated X-ray spectrometer,
(c) wherein the standard is comprised of gold nanoparticles and a matrix powder.

### Claim 10 (depends on 9)

The method of claim 9 wherein the matrix powder is copper.

### Claim 11 (depends on 9)

The method of claim 9 wherein the matrix powder is tin.

### Claim 12 (depends on 9)

The method of claim 9 wherein the matrix powder is silver.