SN/T 5320-2021 in English

Technical background and significance of the standard

With the increasing safety requirements for food packaging, SN/T 5320-2021 has established standardized testing methods for trimellitic acid, isophthalic acid, terephthalic acid and phthalic acid that may migrate from polymer materials. This standard fills the gap in the field of specific migration detection of food contact materials in my country, which is of great significance to ensuring food safety.

Method principle and technological innovation

Method A high performance liquid chromatography combined with an ultraviolet detector was used to achieve baseline separation of the four acids by optimizing the mobile phase gradient (21%-45% methanol). The chromatographic column used a polar end-capped ether biphenyl stationary phase, which significantly improved the separation efficiency.

Analysis of key operating points

Implementation recommendations and precautions

1. The water used in the experiment must comply with the GB/T 6682 first-level water standard
2. The oscillation time (20min±1min) and rotation speed (300r/min) must be strictly controlled during olive oil extraction
3. The temperature of the chromatographic column should be stable at 40℃±1℃
4. The pH value of the phosphate buffer should be verified regularly (2.7±0.1)

Technology evolution analysis

Compared with traditional gas chromatography methods, the HPLC technology used in this standard has the following advantages:

• No derivatization treatment is required
• Four acids with large polarity differences can be detected simultaneously
• The method sensitivity is improved by about 50%
• The operating cost is reduced by 30%