SN/T 5233-2020 in English

Analysis of the core content of the standard

This standard for the first time incorporates Fourier transform near-infrared spectrometer and grating scanning fiber spectrometer into the raw cotton regain detection system, and specifies the technical parameter requirements of the two instruments:

Technical principles and innovations

Rapid detection is achieved by establishing a mathematical model of the raw cotton spectrum and the values measured by the oven method, utilizing the combined frequency absorption band characteristics of water molecules in the near-infrared region. Key technological breakthroughs include:

1. Savitzky-Gloay smoothing and first-order derivative preprocessing are used to eliminate background interference
2. Model transfer technology ensures consistency of results between different instruments (absolute error ≤ 0.5%)
3. Three-dimensional sampling design (front/back/inner layer) reduces the impact of fiber unevenness

Key points of operating specifications

Abnormal handling process

When the difference between two measurements is >0.5% or the result is outside the range of 6-15%, you need to:

1. Check whether the sample contains weeds/foreign fibers
2. Resample and test
3. If still abnormal, switch to the GB/T 6102.1 oven method

Implementation suggestions

Laboratories should pay attention to the following when introducing this standard:

• Instrument verification:Must pass the accuracy (SEP≤1.0%) and repeatability (≤0.5%) verification in Appendix A
• Model maintenance:Use monitoring samples for daily calibration, and remodeling is required if the deviation exceeds the limit
• Staff training:Focus on mastering the spectral acquisition specifications (sampling bottle pressure, rotation speed, etc.)