气体中甲醛含量测定能力验证实验注意事项

Attentions in Experimental Process of Proficiency Testing of Formaldehyde Content in Gas

为了促进用分光光度法测定气态甲醛样品中甲醛含量的能力验证实验,通过气态甲醛样品中甲醛含量的测定实验,对实验过程进行探讨。为了提高检测结果的准确性应注意如下事项:气路各个环节保持良好密封;连接气袋与气瓶或采样管的塑料软管尽量短;由气瓶往气袋放气时,控制气体流量和放气时间;采样时,气袋中的甲醛气体温度应与环境温度一致;合理选择采样流量和采样时间;确保采样前后采样器的流量一样;使用甲醛标准物质进行质量控制;标准系列的浓度范围与能力验证样品接近。

To promote the proficiency testing of formaldehyde content in gas determined by spectrophotometry,the experimental process was discussed through the determination of formaldehyde content in the sample of gaseous formaldehyde.To improve the accuracy of the test results,the following matters should be noted:the gas path is sealed reliable;the length of plastic hoses which connect the bag to the tank or the sampling tube is as short as possible;the flow rate and time of gas released from the tank to the bag can be controlled reasonably;the temperature of formaldehyde in bag must be as same as the temperature of the environment;the appropriate gas flow rate and sampling time can be selected;make sure that the sampler has the same flow rate before and after the sampling;formaldehyde standard material was used for quality control,the concentration range of the standard series was close to the proficiency testing sample.