RESUMEN
Several key aspects for the analysis of inositol hexakisphosphate (InsP6) have been investigated in order to establish a suitable method for the study of sediment samples from different aquatic systems. Apparent matrix effects for the ion chromatography electrospray ionization tandem mass spectrometric detection (IC-ESI-MS/MS) method were accounted for with a standard addition approach, which also compensated for variation in extraction efficiency. Several parameters of the extraction method were optimized to improve the extraction efficiency for different sediment types. We observed an improvement in the extraction efficiency between 18% and 720%. Finally, the method was used to gain first insights into the relevance of InsP6 in two aquatic systems located at the German Baltic coastal area. InsP6 was detected in several sediment samples with concentrations between 2.3 and 15.2⯵g InsP6-P/g dry weight (DW).
RESUMEN
A method for isomeric separation of inositol phosphates (InsPn) in environmental samples originating from different sources such as soil, manure/compost, and aquatic sediments has been developed. The method includes a single NaOH-EDTA extraction step, centrifugation and direct injection of a particle free solution into an ion chromatographic column. Isomeric liquid chromatographic separation was achieved with an ammonium carbonate gradient compatible with electrospray ionization tandem mass spectrometric detection (LC-ESI-MS/MS). The detection limits of the LC-ESI-MS/MS method were between 0.03-0.16µM for the different InsPn, corresponding to 37-99ng P/g sample DW. The method has shown to be able to analyze more than 200 samples from soil, manure and sediment without any severe matrix effects. This will allow future studies of the fate of inositol phosphates in the environment.