LC-MS analysis of nitroguanidine compounds by catalytic reduction using palladium modified graphitic carbon nitride catalyst

Vitaly Nikolaev, Sergey Sladkevich, Uliana Divina, Petr V. Prikhodchenko, Guy Gasser, Luigi Falciola, Mariangela Longhi, Ovadia Lev*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

The analysis of compounds of the nitroguanidine family at trace level poses an analytical challenge. Nitroguanidine, 1-methyl-3-nitroguanidine, and 1-methyl-3-nitro-1-nitrosoguanidine, which are addressed in this article, have low lipophilicity, with log(Kow) equal to −0.89, − 0.84, and 0.68, respectively, and as such are not amenable for preconcentration from water. Liquid-liquid extraction and SPE fail to concentrate them from water and it is also not possible to extract them by ion exchange resin even after a pH change. Nitroguanidine and 1-methyl-3-nitroguanidine nitramines are explosives of growing use and thereby growing environmental concern due to lower detonation sensitivity compared to RDX. A sensitive method for the determination of nitroguanidine, 1-methyl-3-nitroguanidine, and 1-methyl-3-nitroso-1-nitroguanidine by reduction to the respective amines and subsequent hydrophobization by derivatization with 4-nitrobenzaldehyde followed by LC-ESI-MS analysis is described. Reduction by sodium borohydride using palladium modified graphitic carbon nitride (Pd/g-C3N4) provided improved sensitivity compared to the traditional palladium modified activated carbon due to the lower adsorption of the reduction products on the carbon nitride substrate. The limit of detection of the method was 10 ng L−1 for nitroguanidine, and repeated analyses of spiked effluents and contaminated spring water gave relative standard deviations of 8.8% and 6.5%, respectively. The findings illuminate the great promise of Pd/g-C3N4 as a reduction catalyst for the determination of challenging hydrophilic organic contaminants. Graphical abstract: [Figure not available: see fulltext.]

Original languageAmerican English
Article number152
JournalMicrochimica Acta
Volume188
Issue number5
DOIs
StatePublished - May 2021

Bibliographical note

Publisher Copyright:
© 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.

Keywords

  • 1-Methyl-3-nitro-1-nitrosoguanidine
  • 1-Methyl-3-nitroguanidine
  • Aminoguanidine
  • EOC
  • Emerging organic contaminants
  • Graphitic carbon nitride
  • HPLC-MS
  • Nitroguanidine

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