Keywords: Analytical Chemistry
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Evaluation of Phosphorus Release from Lake Sediments Using Passive Sampling and Phosphate Oxygen Isotope Analysis
In eutrophic lakes, the persistent high phosphorus concentration in lake water poses a significant problem. This study employs passive sampling techniques and phosphorus oxygen isotope analysis to identify the sources supplying phosphorus to the lake water. This approach will also reveal contributions from lake sediments, which have not been evaluated previously. This research is expected to contribute to the assessment and conservation of lake water environments.
Akira Hafuka, Takuya Ishida, and Kazuto Sano
The Sumitomo Foundation, Grant for Environmental Research Projects 2025.11.01～2026.11.30
Solid-phase fluorescence excitation-emission matrix spectroscopy of soil, fulvic acid fractions, and clay mineral complexes: Evidence from red shift of fluorescence maxima associated with aggregation
Most of the analysis of natural organic matter (humic substances) in soil is carried out in a solution state by an alkali extraction operation. However, this approach addresses concerns regarding the potential alteration of humic substances during alkaline extraction, which may cause these substances to lose their original structure. In this study, as a non-extraction and non-destructive method, solid-phase fluorescence (excitation-emission matrix) spectroscopy (SPF-EEM) was applied for the first time to a standard humic substance and its complex with clay. It was found that the excitation-emission wavelength could shift according to the state of solution, complex, aggregate, etc.
Yuki Nakaya, Takashi Hirose, Ryuichi Tamori, Nobuhide Fujitake, Satoru Nakashima, Hiroshi Yamamura, and Hisashi Satoh