GB/T 39298-2020 in English
VALIDReclaimed water quality—Determination of benzene homologues—Gas chromatography
- Issued on:2020-11-19
- Implemented on:2021-10-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
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《GB/T 39298-2020再生水水质 苯系物的测定 气相色谱法》由TC63（全国化学标准化技术委员会）归口，TC63SC5（全国化学标准化技术委员会水处理剂分会）执行，主管部门为中国石油和化学工业联合会。
Introduction
Interpretation of the core content of the standard
| Technical elements | Requirements of this standard | Comparison of conventional methods |
|---|---|---|
| Detection range | 0.5-100μg/L | Usually 1-200μg/L |
| Precision control | Relative deviation ≤10% (0.5-10μg/L) | Usually ≤15% |
| Sample preservation | Ascorbic acid + hydrochloric acid double insurance | Mainly single preservative |
Detailed explanation of technical principles
The purge and trap-gas chromatography technology is adopted: the purge and trap device uses a nitrogen flow rate of 40mL/min to blow out the benzene series in the water and enrich them in the carbon fiber/silica gel/activated carbon mixed filler. After thermal desorption at 180℃, it is separated by a polyethylene glycol capillary column and detected by a hydrogen flame ionization detector (FID). Key parameters:
- Programmed temperature: 40℃(6min)→5℃/min→100℃(2min)→5℃/min→200℃
- Separation degree: requirement ≥1.5 (see Appendix A for calculation method)
Key points for implementation of the standard
Typical application scenarios
An abnormal toluene peak was found in a reclaimed water plant. The concentration was confirmed to be 8.3μg/L (RSD=4.7%) through this method. The source was traced back to pipeline leakage of an upstream petrochemical enterprise. After rectification, the concentration was reduced to <1μg/L.
Key operation warnings
- When the residual chlorine is >5mg/L, it is necessary to double the amount of ascorbic acid (every 40mL sample +25mg/5mgCl₂)
- After opening, the standard solution needs to be frozen at -10~-20℃ to avoid response value attenuation
Standard evolution analysis
Compared with the HJ639-2012 surface water method, this standard has the following features:
- New Isopropylbenzene detection indicator
- Lower the detection limit to 0.5μg/L (the original standard is 1μg/L)
- Optimize the purge time to 11min (the original standard is 10min)
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