EDTA extraction followed by 31P-NMR detection. However, some organic P compounds are difficult to extract using NaOH-a href='/search?dc.title=EDTA&facet-content-type=ReferenceWorkEntry&sortOrder=relevance' class='reference-link webtrekk-track' gaCategory="Internal link" gaLabel="EDTA" gaAction="reference keyword">EDTA due to the low solubility, thus can not be detected by 31P NMR. Here, we used foam separation to determine organic P in sediment of North Canal of Tianjin City, China. Organic P was first enriched using foam separation coupled with NaOH extraction. The enriched organic P was then analyzed with 31P NMR. The results showed that, compared with the traditional extraction method, foam separation coupled with NaOH extraction enriched more P compound because 31P NMR detected an extra signal of teichoic acid at chemical shift 1.14. This teichoic acid signal was not detected in the extract prepared using only NaOH-a href='/search?dc.title=EDTA&facet-content-type=ReferenceWorkEntry&sortOrder=relevance' class='reference-link webtrekk-track' gaCategory="Internal link" gaLabel="EDTA" gaAction="reference keyword">EDTA. Our finding demonstrates that determination using foam separation followed by 31P NMR is feasible." />