Quantification of Inositol Hexa-Kis Phosphate in Environmental Samples

Lynne P. Heighton, Merle Zimmerman, Clifford P. Rice, Eton E. Codling, John A. Tossell, Walter F. Schmidt

Department of Chemistry and Biochemistry, University of Maryland, College Park, United States;.
EMBUL ARS, USDA, Beltsville, United States;.

DOI: 10.4236/ojss.2012.21009                

Abstract

Phosphorous (P) is a major contributor to eutrophication of surface waters, yet a complete understanding of the P cycle remains elusive. Inositol hexa-kis phosphate (IHP) is the primary form of organic (P_O) in the environment and has been implicated as an important sink in aquatic and terrestrial samples. IHP readily forms complexes in the environment due to the 12 acidic sites on the molecule. Quantification of IHP in environmental samples has typically relied on harsh extraction methods that limit understanding of IHP interactions with potential soil and aquatic complexation partners. The ability to quantify IHP in-situ at the pH of existing soils provides direct access to the role of IHP in the P cycle. Since it is itself a buffer, adjusting the pH correspondingly alters charged species of IHP present in soil. Density Functional Theory (DFT) calculations support the charged species assignments made based pKas associated with the IHP molecule. Raman spectroscopy was used to generate pH dependent spectra of inorganic (P_I) and IHP as well as (P_O) from IHP and (P_I) in soil samples. Electro-spray ionization mass spectroscopy (ESI-MS) was used to quantify IHP-Iron complexes in two soil samples using a neutral aqueous extraction.

Keywords

Phytic Acid; Inositol Hexkis Phosphate; Electrospray Mass Spectroscopy (ESI-MS); Density Functional Theory (DFT); Raman Spectroscopy

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	C. D. Giles, B. J. Cade-Menun and J. E. Hill, “The Inositol Phosphates in Soils and Manures: Abundance, Cycling and Measurement,” Canadian Journal of Soil Science, Vol. 91, No. 3, 2011, pp. 397-416. doi:10.4141/cjss09090
[2]	B. H. Anderson and F. R. Magdoff, “Relative Movement and Soil Fixation of Soluble Organic and Inorganic Phosphorus,” Journal of Environmental Quality, Vol. 34, No. 6, 2005, pp. 2228-2233. doi:10.2134/jeq2005.0025
[3]	E. O. Young and D. S. Ross, “Phosphate Release from Seasonally Flooded Soils,” Journal of Environmental Quality, Vol. 30, No. 1, 2001, pp. 91-101. doi:10.2134/jeq2001.30191x
[4]	B. L. Turner, M. J. Paphazy, P. M. Haygarth and I. D. McKelvie, “Inositol Phosphates in the Environment,” Philosophical Transactions of the Royal Society B, Vol. 357, No. 1420, 2002, pp. 449-469. doi:10.1098/rstb.2001.0837
[5]	B. J. Turner and P. M. Haygarth, “Biogeochemistry: Phosphorus Solubilization in Rewetted Soils,” Nature, Vol. 411, No. 6835, 2001, p. 258. doi:10.1038/35077146
[6]	B. Bar-Yosef, A. C. Chang and S. Vega, “Organic P Transformations Reactions and Transport in Soils Monitored by 31P NMR Spectroscopy,” Bard Press, Austin, 1993.
[7]	S. Jayasundera, W. F. Schmidt, J. B. Reeves and T. Dao, “Direct 31P NMR Spectroscopic Measurement of Phosphorous Forms in Dairy Manures,” Journal Food, Agriculture and Environment, Vol. 3, No. 2, 2005, pp. 335-340.
[8]	J. C. Hansen, B. Cade-Menton and D. S. Srawn, “Phosphorus Speciation in Manure-Amended Alkaline Soils,” Journal of Environmental Quality, Vol. 33, No. 4, 2004, pp. 1521-1527. doi:10.2134/jeq2004.1521
[9]	A. B. Leytem, P. Kwanyuen, P. W. Plumstead, R. O. Mcguire and J. Brake, “Evaluation of Phosphorus Characterization in Broiler Ileal Digesta, Manure, and Litter Samples: 31P-NMR vs. HPLC,” Journal of Environmental Quality, Vol. 37, No. 2, 2008, pp. 494-500. doi:10.2134/jeq2007.0134
[10]	E. T. Champagne, “Effects of pH on Mineral-Phytate, Protein-Mineral-Phytate, and Mineral-Fiber Interactions. Possible Consequences of Atrophic Gastritis on Mineral Bioavail- ability from High-Fiber Foods,” Journal of the American College of Nutrition, Vol. 7, No. 6, 1988, pp. 499-508.
[11]	L. Heighton, W. F. Schmidt and R. L. Siefert, “Kinetic and Equilibrium Constants of Phytic Acid, Ferric and Ferrous Phytate Derived from Nuclear Magnetic Resonance Spectroscopy,” Journal of Agriculture and Food Chemistry, Vol. 56, No. 20, 2008, pp. 9543-9547. doi:10.1021/jf801465y
[12]	W. Strumm and J. J. Morgan, “Aquatic Chemistry,” John Wiley and Sons Inc., New York, 1996.
[13]	F. M. M. Morel and J. G. Hering, “Principals and Applications of Aquatic Chemistry,” John Wiley and Sons Inc., New York, 1993.
[14]	H. Brinch-Pedersen, L. D. Sorensen and P. B. Holm, “Engineering Crop Plants: Getting a Handle on Phosphate,” Trends in Plant Science, Vol. 7, No. 3, 2002, pp. 118- 125. doi:10.1016/S1360-1385(01)02222-1
[15]	J. Pallauf and G. Rimbach, “Nutritional Significance of Phytic Acid and Phytase,” Archives Animal Nutrition, Vol. 50, No. 4, 1997, pp. 301-319. doi:10.1080/17450399709386141
[16]	S. Y. Khan, “Effects of Dietary Fiber on the Bioavailability of Trace Elements in the Body,” Ph.D. Thesis, University of Karachi, Karachi, 1999.
[17]	J. B. Foresman and A. Frisch, “Exploring Chemistry with Electronic Structure Methods,” 2nd Edition, Gaussian Inc., Pittsburg, 1996.
[18]	L. Heighton, W. F. Schmidt, C. P. Rice and R. L. Siefert, “Electrospray Ionization Mass Spectroscopy Shows Speciation of Phytate to Be pH Dependent,” Journal of Food, Agriculture and Environment, Vol. 6, No. 2, 2008, pp. 402- 407.
[19]	E. E. Codling, R. L. Chaney and C. L. Mulchi, “Use of Aluminum- and Iron-Rich Residues to Immobilize Phosphorus in Poultry Litter-Amended Soils,” Journal of Environmental Quality, Vol. 29, No. 6, 2000, pp. 1924-1931.
[20]	Anonymous, “Sigma Plot User’s Guide: Part 2—Statistics,” Systat Software Inc., 2009.
[21]	V. Barone and M. Cossi, “Quantum Calculation of Molecular Energies and Energy Gradients in Solution by a Conductor Solvent Model,” The Journal of Physical Chem- istry A, Vol. 102, No. 11, 1998, pp. 1995-2001. doi:10.1021/jp9716997
[22]	V. Barone, M. Cossi and J. Tomasi, “Geometry Optimization of Molecular Structures in Solution by the Polarizable Continuum Model,” Journal of Computational Chemistry, Vol. 19, No. 4, 1998, pp. 404-417. doi:10.1002/(SICI)1096-987X(199803)19:4<404::AID-JCC3>3.0.CO;2-W
[23]	M. Cossi, N. Rega, G. Scalamani and V. Barone, “Energies, Structures, and Electronic Properties of Molecules in Solution with the C-PCM Solvation Model,” Journal of Computational Chemistry, Vol. 24, No. 6, 2003, pp. 669- 681. doi:10.1002/jcc.10189
[24]	J. Zhu and R. B. Cole, “Formation and Decompositions of Chloride Adduct Ions, [M + Cl]?, in Negative Ion Electrospray Ionization Mass Spectrometry,” Journal American Society for Mass Spectrometry, Vol. 11, No. 11, 2000, pp. 932-941. doi:10.1016/S1044-0305(00)00164-1
[25]	N. von Wiren, H. Khodr and R.C. Hider, “Hydroxylated Phytosiderophore Species Possess an Enhanced Chelate Stability and Affinity for Iron (III),” Plant Physiology, Vol. 124, No. 3, 2000, pp. 1149-1157. doi:10.1104/pp.124.3.1149