GH/T 1259-2019 in English
VALIDMethod for moisture，total polyphenols and caffeine in tea polyphenol products-Near infrared reflectance spectroscopy
- Issued on:2019-05-21
- Implemented on:2019-12-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
$146.00
Introduction
Analysis of the core content of the standard
This standard establishes a rapid detection system for the three major indicators of tea polyphenol products based on near infrared spectrometer. Its technical principle relies on the frequency-doubled absorption characteristics of the XH vibration of hydrogen-containing groups. Compared with conventional chemical analysis methods, it has the significant advantage of increasing the detection efficiency by more than 80%.
Comparison of key technical indicators
| Test items | SEP upper limit (%) | Repeatability requirement (%) | Allowance deviation (%) |
|---|---|---|---|
| Moisture content | 0.30 | 0.10 | 2.5 |
| Tea polyphenols | 1.50 | 0.40 | 4.0 |
| Caffeine | 0.50 | 0.10 | 5.0 |
Implementation points
Model verification typical case
A testing agency found that the SEP of caffeine exceeded the standard when using the NIRMaster spectrometer for verification. After investigation, it was found that the sample temperature deviated from the calibration temperature by 3℃. After adjustment, the SEP dropped from 0.52% to 0.43%, which met the standard requirements.
Exception handling process
- Check instrument alarm code
- Recheck calibration model matching
- Resample preparation and testing
- Start GB/T 31740.2 arbitration method
Industry application suggestions
It is recommended that manufacturers establish:
- Daily monitoring sample testing system
- Seasonal model update mechanism
- Three-level temperature control system (sample/environment/instrument)
Technology evolution analysis
Compared with the 2015 version of the chemical method, the innovation of this standard is reflected in:
- Detection time is shortened from 4 hours to 5 minutes
- Achieve online monitoring of production lines
- Reduce the use of organic solvents by 90%
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