Aldehyde content of dialdehyde cellulose determined via nitrate analysis

Dialdehyde cellulose was synthesized via the heterogeneous periodate oxidation of microcrystalline cellulose in an aqueous solution. The aldehyde content of the dialdehyde cellulose was determined via nitrate analysis based on a two-step sequential approach. The approach first employed hydroxylamine to react with the aldehyde groups and to produce oxime groups via Schiff’s replacement reaction. Then, the oxime groups were oxidized via persulfate to produce nitrate. The nitrate concentration was analyzed via two highly sensitive methods, i.e., ion chromatography and ultraviolet light absorption. The aldehyde content was approximately one-fifth of the theoretical value. The resulting aldehyde groups were found primarily distributed over the surface layers. A solubility parameter calculation suggested that the increase of the aldehyde groups caused the detachment and dissolution of the dialdehyde cellulose chains and consequently led to the determination of a relatively low aldehyde content.