Speciation of inositol phosphates in lake sediments by ion-exchange chromatography coupled with mass spectrometry, ICP-AES and 31P NMR spectroscopy

This thesis investigates the development of new methodology for the identification and quantification of organic phosphoruscompounds in environmental samples.Phosphorus is a vital element for primary production and one of the factors contributing to eutrophication. Eutrophication of aquatic systems leads to algal blooms, changes in ecological balance and deteriorating water quality. Difficulties in studying organic phosphorusstem from the fact that organic phosphorusis present in the environment in a variety of forms and each form may have different degradation and turnover time, having very different effects on eutrophication.New methods for the quantification of phosphorusderived from three groups of organic phosphoruscompounds were developed. For the determination of phosphorusderived from DNA and phospholipidsselective extraction was combined with digestion and colorimetric determination of the extracted phosphate. For quantification of inositol phosphateshigh performance liquid chromatography was coupled with tandem mass spectrometry using electrospray ionization. The methods were applied to studying the distribution of these compounds in a small catchment and in the case of DNA-P and phospholipid-P, the degradation of the fractions in lake sediments. The studies showed that phosphorusbound to DNA, phospholipidsand inositol phosphatesconstitute a sizeable part of the total phosphorusin different environmental samples. The phospholipid-P fraction was the smallest one, accounting for, on average, only a few percent of the total phosphorusin the sample. Inositol phosphateswere most prevalent in the soils, with inositolhexakisphosphate accounting for over 10% of the total phosphoruscontent. The highest content of DNA-P was found in sediments and it was shown that DNA-P degrades more rapidly than phospholipid-P and therefore plays a more critical role in internal loading.