测定大气中甲醛和氮氧化物用的钝化样品和自制比色计  

HOMEMADE COLORIMETER AND PASSIVE SAMPLER FOR DETERMINATION OF FORMALDEHYDE AND NITROGEN DIOXIDE IN THE ATMOSPHERE

作　　者：陈永康[1] 

机构地区：[1]香港浸会大学化学系,香港666666

出　　处：《广西师范大学学报（自然科学版）》2000年第S1期84-84,共1页Journal of Guangxi Normal University:Natural Science Edition

摘　　要：甲醛和氮氧化物是室内、外空气中的主要污染物 .由于它们对人的毒性危害性很大 ,其他量检测受到重视 .一些采用分光光度计或荧光分析仪的检测法已趋成熟 ,但对一般的中学来说 ,上述仪器的价格过高 ,难以承受 .采用从电子商店购回适用的元件组装成廉价的比色计 ,用于上述检测 .它是以发光二极管 ( LED,绿色LED用于测 NOx,红色的 LED用于测定甲醛 )作为光源 ,光敏电阻作检测器 .当光线穿过样品 ,投射到检测器上 ,光敏电阻的阻值变化通过液晶显示数字万能表 (价值 2 0 0 HK/台 )来测定 .为提高这种方法的灵敏度 ,开发了一种新的钝化样品 .上述组装比色计和钝化样品已在香港浸会大学环境保护课题中使用 .Formaldehyde and nitrogen oxides are major air pollutants in both indoor and outdoor atmosphere.The quantification of both these substances has attracted considerable attention due to its toxicity and potential hazardous effects to human beings.Various spectrophotometric and fluorescent methods have been developed for the determination of these pollutants.Unfortunately,the relatively high cost of the required instruments prevents their acquisition by ordinary secondary schools. We have used components available at electronic stores to fabricate an inexpensive colorimeter that used LEDs (i.e.green LED for NO x and red LED for HCHO) as light sources and a photo resistor as a detector.The amount of light transmitted through the sample and striking the detector is determined by measuring the resistance across the photo resistor,using a LCD digital multimeter (at a cost of 200 HKD).To enhance the sensitivity of the method,a novel passive sampler was developed.Coupled with the use of the homemade colorimeter,the system was used in an environmental project conducted by a group of our students for the determination of the ambient NO x and HCHO content.The students are excited with the hand on experience on the important topic of environmental analysis.

关 键 词：甲醛 氮氧化物 组装比色计 钝化样品 

分 类 号：O6-3[理学—化学]