Methylphosphonic acid as a 31P-NMR standard for the quantitative determination of phosphorus in carbonated beverages

Abstract

Methylphosphonic acid (MPA) is introduced as an internal standard for the determination of the phosphorus content of carbonated beverages (cola drinks) by quantitative 31 P-NMR analysis.Phosphorus in cola beverages was analyzed as phosphate in ten commercially available drinks.Phosphate concentration in the studied samples was in the range of 3.5 to 6.1 mM. The preparation of the samples included: degassing of commercially available beverages, addition of MPA as an internal standard, D 2 O for signal locking and a solution of NaOH to ensure a basic environment in the sample. The calibration graphs of the MPA standard and analyte showed a linear response in the concentration range of interest. The measured values of the phosphoric acid standard solutions lay within the confidence limits of the MPA, showing that these compounds give a similar response in NMR analysis. The measured concentrations of phosphorus were in good agreement with the values detected by the traditional spectrophotometric method. The presented 31 P-NMR method using MPA as an internal standard is reliable and simple for the determination of the phosphorus content of cola type beverages.

1H and 31P benchtop NMR of liquids and solids used in and/or produced during the manufacture of methamphetamine by the HI reduction of pseudoephedrine/ephedrine

“…[11] The chemical shifts for phosphorous acid (phosphite), hypophosphorous acid (hypophosphite) and phosphoric acid (phosphate), as the basic anion, were 2.8, 6.9 and 3.6 ppm, respectively. These values were in agreement with those reported in the literature (phosphorous acid 3.3 ppm [11] , hypophosphorous acid 8.1 ppm [13] and phosphoric acid 5.06 ppm [14] ). The coupling constants for hypophosphorous acid and phosphorous acid, as the basic anion, were 517 and 569 Hz, respectively, and were also in agreement with those reported in the literature (J-coupling hypophosphorous acid 510 Hz and phosphorous acid 570 Hz).…”

Quantitative 31 P-NMR spectroscopy for the determination of fosfomycin and impurity A in pharmaceutical products of fosfomycin sodium or calcium

“…As showed in literature, the accuracy and precision of the quantitative 31 P‐NMR method have been demonstrated to be comparable to chromatographic methods . It has also been proven to be a reliable method for pharmaceutical and food analysis …”

Portland Cement Based Immobilization/Destruction of Chemical Weapon Agent Degradation Products

“…The principal EMPA peak at ∼25 ppm has increased in intensity, and exhibits a shoulder upfield. This is typical of EMPA, but also overlaps with that of MPA. − The asymmetric peak suggests two P environments, potentially due to the presence of MPA. It seems unlikely that other phosphate minerals have been formed during EMPA neutralization.…”