2.4. Nuclear Magnetic Resonance
For the NMR, solutions were mixed with 10-20% D2O to make a total volume of 0.6 ml. The solutions were analyzed in proton-decoupled mode with 3000-7000 scan. Typical run time for a 7000 scan was around 4 hours. The 31P chemical shifts are referenced to phosphoric acid having a chemical shift of 0δ. Standards of known concentration (0.026 µmol/L (8 ppb) to 1614 µmol/L (50 ppm) P were analysed to find the detection limit and building calibration curves. After acquiring the data, phase correction, background correction, peak identification, and area integral calculation were executed in MestReNova software. Area integrals of the peaks were used for building the calibration curve.