Simultaneous quantification of N‐butylthiophosphoric triamide and dicyandiamide in urea formulation by liquid chromatography with tandem mass spectrometry

Abstract

A new liquid chromatography with tandem mass spectrometry method employing a mixed‐mode zwitterionic stationary phase was developed for simultaneous determination of urease inhibitor (N‐butylthiophosphoric triamide) and nitrification inhibitor (dicyandiamide) in urea fertilizer. Molecular modeling based on density functional theory calculations was employed to provide an insight into the interaction mechanism of urea, dicyandiamide, and N‐butylthiophosphoric triamide with zwitterionic stationary phase in chromatographic separation system. The detection of analytes was performed on a triple quadrupole tandem mass spectrometer in multiple reaction monitoring mode using positive electrospray ionization. The ion transitions monitored were m/z 85→68 for dicyandiamide and m/z 168.2→74 for N‐butylthiophosphoric triamide, respectively. The standard calibration curves of dicyandiamide and N‐butylthiophosphoric triamide were linear over the range of 1.0 ̶ 15 ppm (coefficient of determination = 0.9984), 0.05 ̶ 1 ppm (coefficient of determination = 0.9995), with limit of detection of 25 and 5 ppb, respectively. The recoveries of low, middle, and high concentrations were from 96.7 to 105.8% for N‐butylthiophosphoric triamide and 94.4 to 105.8% for dicyandiamide with accuracy (relative error %) of ≤5.8% and ≤5.8%, the precision (coefficients of variation) was ≤2.0% and ≤2.9%, respectively. The validated method was successfully applied on real urea samples to determine N‐butylthiophosphoric triamide and dicyandiamide simultaneously.

Urease and Nitrification Inhibitors—As Mitigation Tools for Greenhouse Gas Emissions in Sustainable Dairy Systems: A Review

“…Due to the presence of both positively charged (quaternary amine like) and negatively charged (carboxyl type) ions in the columns stationary phase, which aided separation through added electrostatic interactions and repulsions of target analytes, both target analytes were linear over a range of 1.0-15 ppm. The respective limits of detection of each of the target analytes were found to be 25 and 5 µg/kg, with recoveries of 96.7 to 105% [118].…”

Quantification of pentaerythritol tetrastearate, a mold release agent used in polycarbonate, by non‐aqueous RP HPLC method

“…The sensitivity of the newly developed method has been checked in terms of LOD and LOQ. The S/N 3:1was used as LOD and 10:1 for LOQ . The LOD and LOQ of the method was found to be 0.03 and 0.05 mg/mL respectively.…”