水样保存方法及保存时间对黄河水体中总有机碳测定的影响

水环境监测中，对于总有机碳的测量，国内外相关标准和规范对其水样保存条件缺乏统一要求。结合黄河水体的水质特点，重点选择pH值、保存时间、保存温度、前处理和水样浓度5个方面评估水样保存条件对总有机碳测试结果造成的影响。结果表明，在采样后24 h内不能及时测试的水样，必须改进保存方法，使水样的pH值小于2、水样运输及保存过程中以4℃冷藏、样品测试前充分混匀、避光密封保存。

Effects of preservation method and holding time of water samples on detection of total organic carbon (TOC) in Yellow River water

In water environmental monitoring , there is no unified demand for water sample preservation in terms of the detection of total organic carbon （ TOC） according to related domestic and international standards .The effects of the water samples ’ preservation conditions , including the pH value , holding time , preservation temperature , pretreatment , and water sample concentration , on the detection of TOC were assessed based on the water quality characteristics of the Yellow River .The results show that , if the samples could not be tested in 24 hours , they have to be acidified to pH ≤2, refrigerated at 4℃ in a refrigerator, homogenized in a blender before detection , and protected from light and atmospheric oxygen .