Peak assignments for phosphorus-31 nuclear magnetic resonance spectroscopy in pH range 5–13 and their application in environmental samples

摘要: Phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy has become popular for the characterization of P species in environmental samples. However, these are commonly made alkaline (pH > 13) to facilitate sample comparison and ease peak identification, but this may cause hydrolysis some compounds. This study examined chemical shift known compounds supplemented with published data determine viability examining samples at their native pH, thereby minimizing disturbance. A 31P NMR pH titration resulted shifts ranging from about −22 8 ppm range 5–13. Categorization calculation over 100 naturally occurring indicated that good distinction between orthophosphate diesters, monoesters, nucleotides, phosphonates, phosphagens was best ≥pH 7, unlikely below pH. Analysis several water extracts soil dung, overland flow samples, lake a w...