1.1 This standard (Part III) prescribes formic acid-zinc chloride method for quantitative chemical analysis of binary mixtures of regenerated cellulose fibres and cotton in textile form, such as fibre, yarn or fabric.
Note —Before conducting an analysis according to this method, the fibres present in the mixture should be identified ( see IS : 667-1955〓 ) and the sample to be analysed shall be freed from all non-fibrous matter by the method given in Appendix A. Dye in the dyed fibres is considered to be an integral part of the fibre and is not to be removed.
1.1.1 This method is not applicable to mixtures in which the cotton has suffered extensive chemical degradation, nor when the viscose, cupro or modal fibre is rendered incompletely soluble by the presence of certain permanent finishes or reactive dyes that cannot be removed completely.
IS 1889 Pt.3-1979 history
1979IS 1889 Pt.3-1979 Quantitative chemical analysis method for binary mixtures of regenerated cellulose fibers and cotton Ⅲ Formic acid-zinc chloride