GB/T 12658-2008 "Determination of Sodium Content in Paper, Cardboard and Pulp" specifies a method for the determination of sodium content in insulating pulp, paper and Cardboard by Flame emission spectrum method or flame atomic absorption spectroscopy (AAS) method. The standard applies to various insulating materials and ordinary pulp, paper and Cardboard, and can accurately detect sodium content and help control the electrical performance and Miscellaneous characteristics of paper. The detection limit of this method can reach 2mg/kg according to the equipment used, which provides a scientific basis for the quality control of related products.