Separation of inositol phosphate isomers in environmental samples by ion-exchange chromatography coupled with electrospray ionization tandem mass spectrometry

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 0.03-0.16 mu M for the different InsP(n), corresponding to 37-99 ng 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. (C) 2016 Elsevier B.V. All rights reserved.