The most useful sorting test for nitrogenous treating agents is the dye staining test, although it does not give specific identification of melamine-formaldehyde resin. The dye staining method is based on the fact that, although acid dyestuffs will not dye cellulose unless mordanted, they combine readily with proteins, such as casein and gelatin. BS 4497 provides guidance on the dye staining method for the detection and estimation of nitrogenous treating agents in the paper.
BS 4497 describes the problems of the detection and estimation of nitrogenous treating agents in the paper and describes both qualitative and quantitative methods for use with certain of these agents, the methods are confined to those substances that have a strong affinity for acid dyes.
BS 4497 on Detection of nitrogenous treating agents in paper is useful for:
The method of estimating the nitrogen content is based on the Kjeldahl process, which is widely used for the determination of organic nitrogen.
BS 4497 gives recommendations for the detection and estimation of nitrogenous treating agents in the paper. The method of estimating the nitrogen content is based on the Kjeldahl process, which is widely used for the determination of organic nitrogen. It is recommended that either selenium or copper sulphate be used as the catalysts which give very satisfactory results on the substances covered by this method.
BS 4497 guidelines help to analyze nitrogenous treating agents in the paper which helps to estimate the protein content in the paper.