How to determine the quality of chemical reagents manufacturers?

The quality assessment of chemical reagents manufacturers needs to be comprehensively evaluated from three aspects: qualification certification, quality standards, and testing processes:
certification
Legitimate manufacturers should possess the following qualifications:
Manufacturer or authorized agent with independent legal personality
Dangerous Chemicals Business License
Imported products require customs declaration and Chinese labels
Must have national mandatory certification (such as 3C certification) and environmental protection certification
quality standard
The quality of reagents must comply with national standards (GB/T 601-2016, etc.) or industry standards, mainly divided into:
High grade purity (GR): ≥ 99.8%, suitable for precision analysis
Analytical purity (AR): ≥ 99.7%, suitable for important analysis
Chemical purity (CP): ≥ 99.5%, suitable for routine analysis
High purity reagents (such as ≥ 99.99%) require special processes for production and are suitable for trace analysis.  ‌
Detection Process
Three steps of inspection need to be completed during acceptance:
Document verification: Verify official documents such as certificates of conformity and production licenses
Appearance inspection: intact packaging, clear label information (name, specifications, batch number, etc.)
Performance testing: Test indicators such as acidity, alkalinity, and concentration based on the characteristics of the reagent