Analytical Chemistry

Scientific Issue and Relevance

Mineral Resources Program and other USGS scientific mission area scientists need specialized routine analysis in order to carry out their research. This project facilitates the ability of the scientific staff to obtain these analyses. The Mineral Resources Program projects require several functions for chemistry to be conducted across theme boundaries. Most of these single efforts are not large enough to support the instrumentation or the expertise needed to work on these tasks. However, when all of the Program's science is considered, then a chemistry support function that combines these efforts results in a cost efficient and necessary endeavor.

Methods to Address Issue

The Analytical Chemistry Project combines and coordinates the chemistry functions that are necessary for research and assessment projects within the Mineral Resources Program, including the Earth Mapping Resources Initiative (Earth MRI).  Our project is responsible for:

• administering the Laboratory Information Management System (LIMS); the system used to track samples and manage in-house and contract analytical data;
• physically preparing samples submitted for analysis;
• validating Geology, Geophysics, and Geochemistry Science Center in-house analytical techniques;
• monitoring contract chemistry data quality, validating contract chemistry analytical results, and disseminating analytical results to staff scientists;
• maintaining and growing the National Geochemical Sample Archive.

Recurring efforts include:

• offering a mechanism to prepare samples;
• maintaining equipment and methods of analysis for in-house analytical chemistry work;
• contracting routine chemical requests to an outside laboratory;
• providing data quality control for both in-house and contract generated data.

Long term efforts include continued support to the Mineral Resources Program by providing these services and modifying the analytical methods or administrative procedures to better meet the needs of the scientists.

Sample and Data Management: We perform all the necessary functions relating to the receipt, processing, preparation, data tracking, quality control, and archiving of samples submitted for chemical analyses. These functions are performed for both in-house and contract laboratory analyses. Sample Control processes on average 15,000-20,000 samples annually. We maintain the Laboratory Information Management System (LIMS), contract out routine analytical chemistry functions, perform quality assurance and quality control (QA/QC) function for all chemical analyses and maintain database for both contract and in-house chemistry, perform physical preparation of samples submitted for chemical analysis. We also operate and maintain the USGS National Geochemical Sample Archive, inventory, and retrieval of previously analyzed powdered geochemical materials.

Media

Sources/Usage: Public Domain. View Media Details

Mineral Separation: We provide Geology, Geophysics, and Geochemistry Science Center scientists with the expertise, equipment, and methods needed to deconstruct rocks and enlarge understanding of geologic processes by separating and concentrating mineral constituents using water tables, heavy liquids, magnets, and microscopes; identifying and quantifying minerals using staining methods and X-ray diffraction, measuring various physical properties of whole rock including density, magnetic susceptibility, and solubility.

X-Ray Fluorescence: We provide high precision determinations of 10 major rock-forming elements as oxides and the determination of minor and trace elements in solid geologic materials using wavelength dispersive x-ray fluorescence. The accuracy achievable using the wavelength dispersive x-ray fluorescence technique for the determination of major elements as oxides is unsurpassed by any other instrumental technique. Samples are prepared and analyzed at our laboratory facility.

Denver Mineralogy Lab: We will continue method development for sample preparation for X-ray diffraction, investigating and implementing advanced X-ray diffraction analyses, and evaluating and interpretating X-ray diffraction scans.

In-House Chemistry Support Services: We provide routine single element and common laboratory support services. Analyses performed include: dissolved organic carbon and percent ash. We also perform single element analyses support for cross checking results from the contract laboratory. In addition to housing the single element analytical capability we also provide common laboratory support services such as the purchase of liquefied and compressed gases, the maintenance and repair of laboratory instrumentation, and the purchase of laboratory supplies such as acids, solvents, glassware, etc.

Contract Chemistry: We monitor the ongoing contract with AGAT Laboratories, Mississauga, Canada, for routine chemical analyses. Our objective is to ensure that all aspects of the contract are executed within the limits established in the statement of work and all performance criteria are met. 

National Geochemical Database: Beginning in FY25, this activity has been merged into this project. We make geochemical data from the National Geochemical Database (NGDB) and the Department of Energy's National Uranium Resource Evaluation (NURE) Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) databases publicly available in various user-friendly formats.

References and Methods 

USGS In-House Methods Reference: Taggart, J.E., 2002, Analytical methods for chemical analysis of geologic and other materials, U.S. Geological Survey: U.S. Geological Survey Open-File Report 02-223, https://doi.org/10.3133/ofr02223. 

Analytical Contract Laboratory Methods:

Contact Jaime Azain for additional information about these methods or obtaining analyses.