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Moens C, Lombi E, Howard DL, Wagner S, Payne JL, Kopittke PM, Doolette CL. Mapping Phosphorus Availability in Soil at a Large Scale and High Resolution Using Novel Diffusive Gradients in Thin Films Designed for X-ray Fluorescence Microscopy. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:440-448. [PMID: 38108297 PMCID: PMC10785753 DOI: 10.1021/acs.est.3c06237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 11/17/2023] [Accepted: 12/01/2023] [Indexed: 12/19/2023]
Abstract
A novel binding layer (BL) as part of the diffusive gradients in thin films (DGT) technique was developed for the two-dimensional visualization and quantification of labile phosphorus (P) in soils. This BL was designed for P detection by synchrotron-based X-ray fluorescence microscopy (XFM). It differs from the conventional DGT BL as the hydrogel is eliminated to overcome the issue that the fluorescent X-rays of P are detected mainly from shallow sample depths. Instead, the novel design is based on a polyimide film (Kapton) onto which finely powdered titanium dioxide-based P binding agent (Metsorb) was applied, resulting in superficial P binding only. The BL was successfully used for quantitative visualization of P diffusion from three conventional P fertilizers applied to two soils. On a selection of samples, XFM analysis was confirmed by quantitative laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The XFM method detected significant differences in labile P concentrations and P diffusion zone radii with the P fertilizer incubation, which were explained by soil and fertilizer properties. This development paves the way for fast XFM analysis of P on large DGT BLs to investigate in situ diffusion of labile P from fertilizers and to visualize large-scale P cycling processes at high spatial resolution.
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Affiliation(s)
- Claudia Moens
- Future
Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
- Division
of Soil and Water Management, KU Leuven, Kasteelpark Arenberg 20, 3001 Heverlee, Belgium
| | - Enzo Lombi
- Future
Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Daryl L. Howard
- Australian
Synchrotron, ANSTO Clayton, Victoria 3168, Australia
| | - Stefan Wagner
- Department
General, Analytical and Physical Chemistry, Chair of General and Analytical
Chemistry, Montanuniversität Leoben, 8700 Leoben, Austria
| | - Justin L. Payne
- UniSA
STEM, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Peter M. Kopittke
- School
of
Agriculture and Food Sciences, The University
of Queensland, St Lucia, Queensland 4072, Australia
| | - Casey L. Doolette
- Future
Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
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Doolette CL, Howard DL, Afshar N, Kewish CM, Paterson DJ, Huang J, Wagner S, Santner J, Wenzel WW, Raimondo T, De Vries Van Leeuwen AT, Hou L, van der Bom F, Weng H, Kopittke PM, Lombi E. Tandem Probe Analysis Mode for Synchrotron XFM: Doubling Throughput Capacity. Anal Chem 2022; 94:4584-4593. [PMID: 35276040 PMCID: PMC8943523 DOI: 10.1021/acs.analchem.1c04255] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Synchrotron-based X-ray fluorescence microscopy (XFM) analysis is a powerful technique that can be used to visualize elemental distributions across a broad range of sample types. Compared to conventional mapping techniques such as laser ablation inductively coupled plasma mass spectrometry or benchtop XFM, synchrotron-based XFM provides faster and more sensitive analyses. However, access to synchrotron XFM beamlines is highly competitive, and as a result, these beamlines are often oversubscribed. Therefore, XFM experiments that require many large samples to be scanned can penalize beamline throughput. Our study was largely driven by the need to scan large gels (170 cm2) using XFM without decreasing beamline throughput. We describe a novel approach for acquiring two sets of XFM data using two fluorescence detectors in tandem; essentially performing two separate experiments simultaneously. We measured the effects of tandem scanning on beam quality by analyzing a range of contrasting samples downstream while simultaneously scanning different gel materials upstream. The upstream gels were thin (<200 μm) diffusive gradients in thin-film (DGT) binding gels. DGTs are passive samplers that are deployed in water, soil, and sediment to measure the concentration and distribution of potentially bioavailable nutrients and contaminants. When deployed on soil, DGTs are typically small (2.5 cm2), so we developed large DGTs (170 cm2), which can be used to provide extensive maps to visualize the diffusion of fertilizers in soil. Of the DGT gel materials tested (bis-acrylamide, polyacrylamide, and polyurethane), polyurethane gels were most suitable for XFM analysis, having favorable handling, drying, and analytical properties. This gel type enabled quantitative (>99%) transmittance with minimal (<3%) flux variation during raster scanning, whereas the other gels had a substantial effect on the beam focus. For the first time, we have (1) used XFM for mapping analytes in large DGTs and (2) developed a tandem probe analysis mode for synchrotron-based XFM, effectively doubling throughput. The novel tandem probe analysis mode described here is of broad applicability across many XFM beamlines as it could be used for future experiments where any uniform, highly transmissive sample could be analyzed upstream in the "background" of downstream samples.
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Affiliation(s)
- Casey L Doolette
- Future Industries Institutes, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Daryl L Howard
- Australian Synchrotron, ANSTO, Clayton, Victoria 3168, Australia
| | - Nader Afshar
- Australian Synchrotron, ANSTO, Clayton, Victoria 3168, Australia
| | - Cameron M Kewish
- Australian Synchrotron, ANSTO, Clayton, Victoria 3168, Australia.,Department of Chemistry and Physics, School of Molecular Sciences, La Trobe University, Melbourne, Victoria 3086, Australia
| | - David J Paterson
- Australian Synchrotron, ANSTO, Clayton, Victoria 3168, Australia
| | - Jianyin Huang
- Future Industries Institutes, University of South Australia, Mawson Lakes, South Australia 5095, Australia.,UniSA STEM, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Stefan Wagner
- Chair of General and Analytical Chemistry, Montanuniversität Leoben, Leoben 8700, Austria.,Institute of Analytical Chemistry, University of Natural Resources and Life Sciences Vienna, Tulln 3430, Austria.,Institute of Soil Research, University of Natural Resources and Life Sciences Vienna, Tulln 3430, Austria
| | - Jakob Santner
- Institute of Agronomy, University of Natural Resources and Life Sciences Vienna, Tulln 3430, Austria
| | - Walter W Wenzel
- Institute of Soil Research, University of Natural Resources and Life Sciences Vienna, Tulln 3430, Austria
| | - Tom Raimondo
- Future Industries Institutes, University of South Australia, Mawson Lakes, South Australia 5095, Australia.,UniSA STEM, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | | | - Lei Hou
- Future Industries Institutes, University of South Australia, Mawson Lakes, South Australia 5095, Australia.,The University of Queensland, School of Agriculture and Food Sciences, St Lucia, Queensland 4072, Australia
| | - Frederik van der Bom
- The University of Queensland, School of Agriculture and Food Sciences, St Lucia, Queensland 4072, Australia
| | - Han Weng
- The University of Queensland, School of Agriculture and Food Sciences, St Lucia, Queensland 4072, Australia
| | - Peter M Kopittke
- The University of Queensland, School of Agriculture and Food Sciences, St Lucia, Queensland 4072, Australia
| | - Enzo Lombi
- Future Industries Institutes, University of South Australia, Mawson Lakes, South Australia 5095, Australia.,UniSA STEM, University of South Australia, Mawson Lakes, South Australia 5095, Australia
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