Establishment of Standard Reference Material Purity by Using 31P FT-NMR Comparison to Surrogate Material

Abstract

Chromatography, thermal methods, and other associated physical determinations have been applied to the assignment of purities to standard reference materials. Each of these techniques has limitations, and each generally requires a primary standard of known purity. The establishment of purities on organophosphorus compounds can easily be performed without the availability of a typical primary standard by using proton decoupled 31P FT-NMR comparison to surrogate materials of known purity. A proposed analytical standard reference material of oxydemeton-methyl was evaluated using a 7.3 Tesla FT-NMR (300 MHz proton) using inverse-gated WALTZ decoupling. The resulting phosphorus singlet was compared with that of trlmethyl phosphate. This technique for purity assignment was confirmed by 2 additional experiments: (1) comparison of an established standard and a blind sample of demeton-S-methyl (Metasystox-I®) , with trlmethyl phosphate and (2) comparison of an established standard of disulfoton (Dl-Syston®) vs 0,0,0-trimethyl phosphorothloate.

Method Performance and Validation for Quantitative Analysis by 1H and 31P NMR Spectroscopy. Applications to Analytical Standards and Agricultural Chemicals

“…Reported applications of 31 P QNMR include analysis of phospholipids mixtures − and determination of inorganic phosphorus and organophosphorus compounds. ,, Quantitative 31 P NMR has also become an indispensable tool for the lignin chemist. − …”

“…19 Reported applications of 31 P QNMR include analysis of phospholipids mixtures [20][21][22] and determination of inorganic phosphorus 23 and organophosphorus compounds. 2,3,24 NMR has also become an indispensable tool for the lignin chemist. [25][26][27][28][29][30][31] Proton QNMR has been applied to determine "octane number" in gasoline, 32,33 active ingredients in pharmaceutical formulations, 34,35 analysis of organic osmolytes and their metabolites in crude plant tissue extracts, 36 determination of intracellular pH, 37 and in polymer chemistry to determine acrylic unsaturation in ultraviolet light-curable resins.…”