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美国公共卫生协会1977年介绍,测定气体中甲醛的标准方法采用1,8-二羟萘-3,6-二磺酸(CA)法,而测定气体中总醛量则用3-甲-2-苯并噻唑腙(MBTH)法。本文作者在实验过程中发现二种方法多有重复,步骤复杂,操作繁琐,故根据二个实验的基本原理,合二为一,同时大大简化了操作步骤,而所得实验结果与二种方法一致。现将该实验步骤简介如下: 一、串连两个气泡吸收管(内含20 ml0.05%MBTH液)进行采样,采样速度与体积视气体中估计甲醛浓度而定。二、将样本用0.05%MBTH液稀释至50 ml。三、测甲醛:取4 ml样本稀释液至试管中,加入0.1 ml 1%CA液,随后加入6 ml浓硫
The American Society of Public Health introduced in 1977, the standard method for the determination of formaldehyde in the gas using 1,8-dihydroxynaphthalene-3,6-disulfonic acid (CA) method, and the determination of the total amount of the gas with 3-methyl -2 - Benzothiazyl hydrazone (MBTH) method. In the course of experiment, the author found that the two methods are repetitive, the steps are complicated and the operation is cumbersome. Therefore, according to the basic principles of the two experiments, the two methods are combined together, and the operation steps are greatly simplified, and the experimental results obtained are consistent with the two methods . Now the experimental steps are as follows: First, the two bubble tube in series (containing 20 ml0.05% MBTH liquid) for sampling, sampling speed and volume depending on the estimated concentration of formaldehyde gas may be. Second, the sample diluted with 0.05% MBTH solution to 50 ml. Third, the test formaldehyde: Take 4 ml of sample dilution to the test tube, add 0.1 ml 1% CA solution, followed by the addition of 6 ml of concentrated sulfur