This part of GB/T 19421 specifies the method for the determination of pH in layered crystalline sodium disilicate. This section applies to the determination of the pH value of layered crystalline sodium disilicate aqueous solution that can be used as a detergent builder.
GB/T 19421.3-2003 history
2008GB/T 19421-2008 Test methods of crystalline layered sodium disilicate
2003GB/T 19421.3-2003 Test methods of crystalline layered sodium disilicate--Method for determination of pH
GB/T 19421.3-2003 Test methods of crystalline layered sodium disilicate--Method for determination of pH was changed to GB/T 19421-2008 Test methods of crystalline layered sodium disilicate.