Quantitative analysis of iodine and bromine in soil using an energy-dispersive X-ray fluorescence spectrometer with three-dimensional polarized optics.

A nondestructive and simple method for the determination of bromine and iodine in soil was investigated using an energy-dispersive X-ray fluorescence spectrometer equipped with three-dimensional polarized optics. Using a gadolinium X-ray tube and Mo and Al2O3 as optimal secondary target materials, K-lines were detected for bromine and iodine. The minimum detection limits for bromine and iodine were calculated using JSAC0411, a certified reference material of soil for metal composition analysis, and were 0.77 mg/kg for bromine and 2.3 mg/kg for iodine at a measurement time of 600 s. The results of the determination of bromine and iodine in soil samples by the standard addition method were 256 ± 8 mg/kg for iodine and 67.9 ± 1.3 mg/kg for bromine with JSAC0411, which were in close agreement with the results measured by inductively coupled plasma mass spectrometry (ICP-MS) after alkaline extraction with tetramethylammonium hydroxide (TMAH) solution. The method developed in this study is an excellent technique for direct analysis of soil by X-ray fluorescence analysis without any pretreatment such as alkaline extraction. It is expected to be a practical analytical method for elucidating the dynamics of bromine and iodine in agricultural land and soil.

Uptake and accumulation mechanisms of hexachloroplatinate(IV) ions in the unicellular alga, Pseudococcomyxa simplex.

Platinum uptake was examined by adding hexachloroplatinate(IV) solution to the unicellular alga Pseudococcomyxa simplex. After the addition of platinum solution ([Pt] = 100 mg/kg, pH 3.2-3.2) for a certain time, the cells were quickly frozen and subjected to µ-XRF (X-ray fluorescence) analysis using synchrotron X-rays. The beam size of approximately 1 micrometer allowed visualization of the platinum distribution within a single cell. On the other hand, we examined platinum uptake in enzyme-treated protoplasts and lyophilized cells and found that the platinum uptake concentrations in these samples were higher than in living in-vivo cells. Cell wall and cell metabolism were presumed to interfere with the uptake of hexachloroplatinate(IV) ions. All platinum ions taken up by the cells were reduced to divalent form. The effect of light on platinum addition was also investigated. When platinum was added under light conditions, some samples showed higher platinum accumulation than under shade conditions.