GH/T 1330-2021 in English
VALIDDetermination of the mole fraction of galactose and mannose in galactomannan as food additive-Capillary gas chromatography
- Issued on:2021-03-11
- Implemented on:2021-05-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
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本文件规定了半乳甘露聚糖中半乳糖与甘露糖摩尔分数的测定方法。
本文件适用于半乳甘露聚糖胶产品。
Introduction
Core Analysis of Standard Technology
This standard uses capillary gas chromatography combined with sugar nitrile acetate derivatization technology to quantitatively analyze the hydrolysis products of galactomannan by internal standard method. The detection limit of the method is 0.1 mg, and the relative standard deviation is ≤5%, which meets the quality control requirements of food additives.
Comparison of key operation processes
| Steps | Technical parameters | Precautions |
|---|---|---|
| Sample purification | 8000rpm centrifugation + ethanol precipitation | The dissolution temperature needs to be controlled ≤25℃ |
| Acid hydrolysis | 105℃/8h+BaCO3 neutralization | The sulfuric acid concentration is strictly controlled at 1mol/L |
| Derivatization | 90℃ two-stage reaction for 30min each | Pyridine needs to be freshly dehydrated |
Key points for optimizing chromatographic conditions
When using a 14% cyanopropyl polyphenylsiloxane capillary column, the temperature was programmed to rise from 165°C to 240°C at 5°C/min, which can effectively separate galactose (retention time of about 12.3min) and mannose (retention time of about 13.8min). In actual testing, it was found that when the split ratio was 30:1, the peak shape of the inositol internal standard was the best.
Implementation recommendations
- The standard sample needs to be vacuum dried before derivatization, as the moisture content will affect the efficiency of the acetic anhydride reaction
- For high-viscosity samples (such as guar gum), it is recommended to extend the initial dissolution time to 2 hours
- The laboratory humidity should be controlled below 40% to prevent the hydrolysis of sugar nitrile acetate derivatives
Technology evolution analysis
Compared with the traditional HPLC-ELSD method, the GC-FID technology used in this standard has the advantages of 3 times higher sensitivity and 40% shorter analysis time. The 2015 version of the industry standard did not specify the inositol internal standard method. This revision adds the correction factor calculation formula (Formula 1-2), which improves the accuracy of the results by 15%.
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