Determination of chromium in natural waters by flow injection inductively coupled plasma emission spectrometry.

A successful approach for the accurate determination of chromium species in river waters is developed in this thesis. This is based on the use of alumina micro columns for in situ sampling and storage, followed by a simple introduction of the in situ samples to an inductively coupled plasma emission spectrometer using a flow injection manifold.The approaches to speciation determination have been reviewed in Chapter 1. The need for in situ sampling and separation together with storage stability is evident, as is the limited success reported for many elements including chromium. Alumina is shown to be a material with promising characteristics for sampling and separation, and its properties as an ion exchanger are described.Chapters 3 and 4 deal in turn with the investigation of the properties and application of the acidic and basic form of activated alumina for the determination of chromium species. The results provide the basic knowledge for the subsequent development of the methodology for in situ river sampling and analysis reported in Chapter 5.Very successful results are reported. For the first time river water samples have been obtained for chromium species and transferred to the laboratory without any significant change in speciation. The methodology is simple and effective for the two river waters investigated. The concentration ranges found in the River Rother were 1.7 to 3.1 mug/l chromium (VI) and 8.6 to 19.5 mug/l for chromium (III). Similar results are reported for the River Don.