Optimizing pretreatment for the detection of phosphorus oxyanions using ion chromatography

Phosphorus (P) is required for all living organisms. Fully oxidized pentavalent (+V) is the principal form in organisms, however studies on Desulfotignum phosphitoxidans show the enzymatic metabolism of reduced P oxyanions. Thus a natural source of reduced P is expected. Geothermal waters are naturally occurring reducing environments and ion chromatography has been used for the detection of submicromolar concentrations of P, yet the detection of reduced oxyanions is complicated by fluoride and hydrogen carbonate with similar elution times as hypophosphite(+I) and phosphite(+III) respectively. Studies had shown that simplifying the matrix through pretreatment with silver and sulfonic acid cartridges improves IC limits of detection (LODs). The effects of pretreatment are dependant upon the total concentration of ions in solution. The purpose of this study is to determine IC phosphorous oxyanion LODs and to maximize signals by analyzing the relationship between filtering techniques, effective concentration of P oxyanions, and total ions in the matrix.