title: A new method for the determination of the nitrogen content of nitrocellulose based on the molar ratio of nitrite-to-nitrate ions released after alkaline hydrolysis.
abstract: A new method was proposed to determine the nitrogen content of nitrocelluloses (NCs). It is based on the finding of a linear relationship between the nitrogen content and the molar ratio of nitrite-to-nitrate ions released after alkaline hydrolysis. Capillary electrophoresis was used to monitor the concentration of nitrite and nitrate ions. The influences of hydrolysis time and molar mass of NC on the molar ratio of nitrite-to-nitrate ions were investigated, and new insights into the understanding of the alkaline denitration mechanism of NCs, underlying this analytical strategy is provided. The method was then tested successfully with various explosive and non-explosive NC-containing samples such as various daily products and smokeless gunpowders. Inherently to its principle exploiting a concentration ratio, this method shows very good repeatability in the determination of nitrogen content in real samples with relative standard deviation (n = 3) inferior to 1.5%, and also provides very significant advantages with respect to sample extraction, analysis time (1h for alkaline hydrolysis, 3 min for electrophoretic separation), which was about 5 times shorter than for the classical Devarda's method, currently used in industry, and safety conditions (no need for preliminary drying NC samples, mild hydrolysis conditions with 1M sodium hydroxide for 1h at 60 °C).
authors.affiliation: PSL Research University, Chimie ParisTech, Laboratory of Physicochemistry of Electrolytes, Colloids and Analytical Sciences (PECSA), 11 rue Pierre et Marie Curie, 75005 Paris, France; Central Laboratory of Police Prefecture (LCPP), 39 bis rue de Dantzig, 75015 Paris, France; CNRS, UMR 7195 PECSA, 11 rue Pierre et Marie Curie, 75005 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, LBM, 4 place Jussieu, F-75005 Paris, France. Electronic address: elodie.alinat@chimie-paristech.fr.
authors.forename: Elodie
authors.initials: E
authors.lastname: Alinat
authors.affiliation: PSL Research University, Chimie ParisTech, Laboratory of Physicochemistry of Electrolytes, Colloids and Analytical Sciences (PECSA), 11 rue Pierre et Marie Curie, 75005 Paris, France; CNRS, UMR 7195 PECSA, 11 rue Pierre et Marie Curie, 75005 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, LBM, 4 place Jussieu, F-75005 Paris, France. Electronic address: nathalie.delaunay@espci.fr.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Delaunay
authors.affiliation: Central Laboratory of Police Prefecture (LCPP), 39 bis rue de Dantzig, 75015 Paris, France. Electronic address: xavier.archer@interieur.gouv.fr.
authors.forename: Xavier
authors.initials: X
authors.lastname: Archer
authors.affiliation: École Normale Supérieure-PSL Research University, Département de Chimie, 24 rue Lhomond, 75005 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, LBM, 4 place Jussieu, F-75005 Paris, France; CNRS, UMR 7203 LBM, F-75005 Paris, France. Electronic address: jean-maurice.mallet@es.fr.
authors.forename: Jean-Maurice
authors.initials: JM
authors.lastname: Mallet
authors.affiliation: PSL Research University, Chimie ParisTech, Laboratory of Physicochemistry of Electrolytes, Colloids and Analytical Sciences (PECSA), 11 rue Pierre et Marie Curie, 75005 Paris, France; CNRS, UMR 7195 PECSA, 11 rue Pierre et Marie Curie, 75005 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, LBM, 4 place Jussieu, F-75005 Paris, France. Electronic address: pierre.gareil@chimie-paristech.fr.
authors.forename: Pierre
authors.initials: P
authors.lastname: Gareil
mesh_terms: D003101:Collodion / Q000737:chemistry*; D004586:Electrophoresis; D019075:Electrophoresis, Capillary; D006868:Hydrolysis; D007477:Ions; D007700:Kinetics; D009566:Nitrates / Q000737:chemistry*; D009573:Nitrites / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry; D015203:Reproducibility of Results; D012972:Sodium Hydroxide / Q000737:chemistry; D013696:Temperature
chemical_list: D007477:Ions; D009566:Nitrates; D009573:Nitrites; D012972:Sodium Hydroxide; D003101:Collodion; D009584:Nitrogen
keywords: Alkaline hydrolysis; Nitrocellulose; Nitrogen content; Smokeless gunpowder