空气中甲醛现场测定仪的方法特性研究
A Colorimetric Method for the Determination of Formaldehyde in Air in the Field
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摘要:目的 基于酚试剂比色原理, 针对固定波长、采样与比色同时在现场完成的甲醛现场测定仪进行检测方法特性研究, 为建立空气现场比色法的国家或行业标准提供依据。方法 按照我国《环境监测分析方法标准制修订技术导则》 (HJ 168-2010) 的规定, 进行方法特性指标的评估, 同时在30 m3人工模拟环境舱发生不同浓度甲醛, 测定结果与国家标准《公共场所空气中甲醛测定方法》 (GB/T 18204.26-2000) 进行比对。结果 该法检出限0.052 μg/10 mL吸收液, 检测下限0.17 μg/10 mL吸收液, 若采样体积6 L, 方法最小检测浓度0.028 mg/m3。相对标准偏差2.3% ~ 7.3%, 平均加标回收率为99.2% ~ 108.7%。与国家标准方法比对的相对误差≤5%。结论 该类基于固定波长比色原理的测定仪特性指标满足甲醛浓度的测定要求, 同时采样、分析可以在现场完成, 减少了传统方法采样后带回实验室分析的环节, 为空气甲醛现场检测提供了一种快速、简便的分析手段。Abstract:Objectives Based on the coloring of phenol reagent with formaldehyde, a colorimeter with fixed wavelength was developed in order to complete the sampling and determination of formaldehyde in air in the field.Method According to the rule in the "Environmental Monitoring-Technical Guideline on Drawing and Revising Analytical Method Standards "(HJ168-2010), the technical indexes of the method were evaluated.The concentration of formaldehyde in the air from a 30 m3 artificially simulating environmental tank tested by this method was compared with that by the "National Standard Method for Determination of Formaldehyde in Air of Public Places"(GB/T 18204.26-2000).Results The detection limit and the determination limit were 0.052 μg and 0.17μg respectively in 10 mL of absorption liquid (absorbed from 6 liters of air).The relative standard deviation was from 2.3 % to 7.3%, the recovery was between 99.2% and 108.7%, the relative error of the method was less than 5% compared with the National Standard Methods.Conclusion Through technical index assessment, this is a quick and easy method for analyzing formaldehyde in air and the reports could be finished in the field.
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