Highly sensitive flow analysis determination of orthophosphate using solid phase enrichment of phosphomolybdenum blue without need for organic solvents in elution Original Research Article

In a flow analysis configuration, orthophosphate has been enriched as phosphomolybdenum blue on reversed phase polymers (styrene-divinylbenzene (DVB), methacrylate, dextran), recovered by an alkaline solution without added organic solvent, and measured photometrically at 700 nm. It was found that phosphomolybdenum blue is bound to those polymers mainly by fast adsorption but also partly by slow diffusion (which causes some carryover); the relative extent of both processes depends on the chemical nature of the polymer. With the enrichment column placed near the detector to minimize transport dispersion and an enrichment time of 120 s; a signal improvement factor of 30–50 was obtained using styrene-DVB.