Ma. Nanny et Ra. Minear, CHARACTERIZATION OF SOLUBLE UNREACTIVE PHOSPHORUS USING P-31 NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY, Marine geology, 139(1-4), 1997, pp. 77-94
P-31-NMR spectra of soluble unreactive phosphorus (SUP) were obtained
over a year from a small mid-western lake (Crystal Lake). Lake water s
amples were concentrated with ultrafiltration (UF) and reverse osmosis
membranes (RO). These membranes were also used to fractionate the SUP
according to molecular weight. A sample from the Mississippi River wa
s also analyzed with P-31-NMR. Diester and monoester phosphates, phosp
honates, tri- and/or tetrapolyphosphates, and orthophosphate were dete
cted in these samples. Use of the lanthanide shift reagent (LSR) prase
odymium ethlylenediamine tetraacetate, alkaline bromination degradatio
n procedures, and adjustment of sample pH in conjunction with P-31-NMR
spectroscopy provided additional information regarding the SUP. It wa
s found that the SUP pool exists as a variety of organic phosphorus co
mpounds which vary with respect to their apparent molecular size. Seco
ndly, P-31-NMR data from Crystal Lake demonstrate that the SUP composi
tion varies as a function of season and/or general lake conditions. Th
irdly, comparison of Crystal Lake and Mississippi River spectral data
shows that the SUP composition differs between distinct hydrological s
ites. P-31-NMR spectral data, in conjunction with other information su
ch as LSR data, pH adjustment data, and alkaline bromination data, als
o illustrate that a portion of the SUP may become incorporated into an
aggregate that forms during UF/RO concentration procedures. (C) 1997
Elsevier Science B.V.