GB/T 40272-2021 in English

This standard specifies the detection method for determining 7 acid-soluble metal elements in paper materials using atomic absorption spectrometer (AAS) or inductively coupled plasma optical emission spectrometer (ICP-OES). The main technical features include:

• Detection limit range: 0.4mg/kg for magnesium to 1.2mg/kg for potassium
• Sample pretreatment: classic process of 525℃ incineration + acid dissolution
• Method compatibility: covers both traditional paper products and emerging cellulose nanomaterials

Key steps in sample processing

1. Ashing control: Avoid flames that may lead to the formation of acid-insoluble substances such as copper-platinum alloys
2. Sample weight recommendations:
   • Major elements (magnesium/calcium/sodium/potassium): 1-2g
   • Trace elements (manganese/iron/copper): 5-10g
3. Special treatment for nanomaterials: The suspension must be dried first, and filtering pretreatment is prohibited

Instrumental analysis precautions

Laboratory capacity building

• Staff requirements: Must have formal chemical laboratory work experience
• Equipment configuration: AAS and ICP-OES dual platform verification is recommended
• Quality control: Regular standard material verification

Special sample processing

For high-silicon samples, microwave digestion may result in low magnesium detection values. It is recommended to use this standard ashing method first.

This standard adopts ISO12830:2019 through modification, and the main technical evolution is reflected in:

• Expansion of detection scope: New detection of magnesium and calcium elements to meet the domestic regulatory needs of papermaking additives
• Localization adaptation: All referenced documents are converted to the national standard system
• Improvement of technical details: Supplementation of practical terms such as solution storage conditions and metal purity requirements

According to the inter-laboratory comparison data in Appendix A, the reproducibility limit of calcium determination for conventional paper products in this standard can reach 15.4mg/kg, and the repeatability limit of magnesium determination for cellulose nanomaterials is 5.7mg/kg.