Publications by authors named "Johan Ingri"

The ferrihydrite-backed DGT (diffusive gradients in thin films), recently developed for arsenic and phosphate measurements was, for the first time, characterized with respect to molybdate, antimonate, vanadate and tungstate determination. Arsenate was included in the characterization to allow comparison with literature data and thus provide quality control of the measurements. In addition to laboratory experiments, field measurements were carried out in a natural stream in northern Sweden affected by mine drainage.

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Diffusive gradients in thin films (DGT) and ultrafiltration were used to measure trace metal concentrations in the Baltic Sea. The results provide the first comparison of these two fundamentally different speciation methods for trace metals. Cd, Cu, Mn, Ni, and Zn were measured at two sites with different total trace metal concentrations.

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A procedure was developed for the determination of element distributions in cross-sections of ferromanganese concretions using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The effects of carrier flow rates, rf forward power, ablation energy, ablation spot size, repetition rate and number of shots per point on analyte intensity were studied. It is shown that different carrier gas flow rates are required in order to obtain maximum sensitivities for different groups of elements, thus complicating the optimisation of ICP parameters.

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Article Synopsis
  • Accurate isolation of colloidal phases in natural waters is important for understanding trace metal and organic compound availability, but the process has challenges in distinguishing these substances from smaller counterparts.
  • The study compared two cross-flow filtration (CFF) systems, one large and widely used, the other smaller and less known, establishing that a specific cross-flow ratio (CFR) above 15 is essential for effective colloid recovery.
  • Results indicate that applying a CFR > 15 and a concentration factor (cf) > 10 yields nearly complete recoveries of various elements and confirms expected trends in their coordination chemistry in Baltic Sea waters.
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Two acid digestion procedures (microwave-assisted and room temperature) were developed for the quantitative analysis of ferromanganese nodules by inductively coupled plasma double focusing sector field mass spectrometry (ICP-SFMS). Different compositions of the acid mixture, dilution factors and corrections for spectral interferences were tested. A combination of nitric, hydrochloric and hydrofluoric acids is necessary for complete sample digestion, with lowest acid to sample ratios (v/m) of 15 and 1.

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