| Summary: | Abstract The high demand for raw materials has increased interest in mining in the northern latitudes. However, mining and mineral processing may pose risks to the environment, which is especially vulnerable in the Arctic region. Xanthates are a group of chemicals used in mineral processing that have recently raised concern. They can be toxic to aquatic environments, even at low concentrations. The toxicity of xanthates is mostly related to their decomposition products, such as carbon disulfide. The amounts of xanthates that are at risk of being discharged into the environment are so low that few methods are capable of reliably determining these concentrations. The first aim of this dissertation was to develop new, selective methods for the determination of low xanthate concentrations in process and environmental waters. The second aim was to study the effect of cold climates on the decomposition of xanthates. The studies were conducted at laboratory scale using artificial samples and samples collected from a mine site located in Finland. In this study, two analysis methods were developed. Both methods were based on the determination of xanthate derivatives by high-performance liquid chromatography tandem mass spectrometry (HPLC-ICP-MS/MS). The sample preparation procedures developed were based on oxidation and the complex formation reactions of xanthates; the former was applied when the decomposition of xanthates was studied in artificial and real samples. The results showed that the HPLC-ICP-MS/MS technique enables the selective determination of low xanthate concentrations. However, the complexity of the chemical reactions of xanthates required careful optimization of the sample preparation procedures to improve their reliability. Additionally, decomposition studies showed that low temperatures significantly decrease the decomposition rate of xanthates. This study presents a pioneering step to improve the analysis methods for the determination of xanthates. It also implies that cold climate conditions should ...
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