Application of nonselective 1D (1)H-(31)P inverse NMR spectroscopy to the screening of solutions for the presence of organophosphorus compounds related to the chemical weapons convention

1D nonselective (1)H-(31)P HSQMBC, HSQC, and (31)P decoupled HSQC NMR experiments were applied to the screening of original OPCW proficiency test samples for the presence of organophosphorus (OP) compounds related to the Chemical Weapons Convention. The HSQC and HSQMBC spectra are compared to 1D (1)H NMR spectra with WET solvent suppression and (31)P[(1)H] spectra of the same samples. The 1D nonselective HSQC and HSQMBC experiments are shown to be the most sensitive NMR experiments to selectively screen samples for the presence of organophosphorus(OP) compounds. These experiments are at least three times more sensitive than the (31)P[(1)H] NMR experiment and allow the determination of the number of OP compounds present in the sample and their alkyl group bound to the phosphorus atom. Samples spiked at the 5-10 ppm level can be screened within an hour for the presence of OP compounds, whereas for the (31)P[(1)H] experiments, an overnight acquisition is necessary. The sensitivity of the experiments decreases in the order (31)P decoupled HSQC, HSQMBC, and HSQC. For the different alkyl groups, the sensitivity of these experiments decreases in the order methyl approximately isopropyl > ethyl > propyl.