XANES-SiVM data processing for redox microsite detection

Knowledge graph centered on XANES-SiVM data processing for redox microsite detection with 55 nodes and 157 connections. Top connected: Potentilla, Bacteria, Potentilla pulcherrima, groundwater storage dynamics, carbon cycling.

Method synopsis

Combined XANES fitting and Simplex Volume Maximization analysis to identify and quantify redox microsites while eliminating false positives.

Synthesized from method descriptions across 1 paper using this protocol.

Procedure as described in the canonical source

Steps below were extracted from the paper that introduces this protocol — X-ray chemical imaging for assessing redox microsites within soils and sediments (2024), Frontiers in Environmental Chemistry. Implementations in other papers (listed below) may differ.

1. Process X-ray data using XANES fitting
   Data processing of Fe K-edge multiple energy μ-XRF maps involved fitting the six-point XANES spectrum of each pixel with a set of selected full XANES spectra across the Fe K-edge using XANES fitting. Reference compounds included FeII-(hydroxy)oxide, FeII-S, and FeIII CO3 microsites in FeIII-free sand core.
   Quantities: Six-point XANES spectrum per pixelDuration: Post-collection analysisConditions: Computational analysis
   Equipment: XANES fitting software, reference compound spectra
2. Apply Simplex Volume Maximization fitting
   The SiVM method is a non-negative matrix factorization algorithm which geometrically selects data points that are furthest away from each other in multi-dimensional space, within a user-defined noise threshold. This process effectively selects a set of endmembers, where all of the data points can be calculated as a linear-combination of these endmembers.
   Quantities: User-defined noise threshold appliedDuration: Post-collection analysisConditions: Computational analysis with noise threshold
   Equipment: SiVM analysis software

Typical Equipment

• XANES fitting software
• SiVM analysis software

Output Measurements

• redox microsite maps
• Fe speciation quantification

Papers Using This Protocol (1)

Species Studied With This Protocol

Places Where Used