1, look at the reflection of animals and plants
You can put some green plants indoors, or raise some small animals to test whether formaldehyde exceeds the standard. If within a certain period of time, small animals get sick, don't like to eat, their activities decrease, and a large number of plants wither, it means that the formaldehyde content in the house exceeds the standard.
2. self-perception.
It is judged according to your own feelings. For example, after you just moved into a new house, your family caught a cold, your collective immunity decreased, you felt dizzy, your energy decreased, and you were easily tired, or you obviously felt a pungent smell, your eyes were uncomfortable, and you even shed tears for no reason. At this time, first keep indoor ventilation and do a professional formaldehyde test as soon as possible.
3, formaldehyde detection box
The formaldehyde detection box is cheap and simple to use, which is most suitable for individuals to carry out indoor testing by themselves. The specific operation is as follows: Before the test, seal the test space 1 hour, then open the absorption box, pour all white bottles of reagents into the absorption box, cover the absorption cover, and gently shake the absorption box until the contents are completely dissolved.
Then open the absorption box to prevent it from being in the measured space for 30 minutes, then completely pour the brown reagent into the absorption box, shake it gently, cover the box and let it stand for 10 minutes, compare the color with the color card, and read the formaldehyde concentration value in each cubic meter of air in the measured space. However, the accuracy of formaldehyde detection box is very poor, and only a qualitative rough judgment can be made. This method is not advisable if we want to obtain accurate numerical values.
4, formaldehyde detector
There are several hundred, one or two thousand formaldehyde detectors sold on the market and online, and the test data is inaccurate. Please choose carefully. The test results of a really good formaldehyde detector are relatively accurate, but the price of an accurate formaldehyde detector is not cheap, ranging from several thousand yuan to hundreds of thousands of yuan.
5. Purple and black
After adding purple and black, it can be used as a simple formaldehyde detection tool according to the color change of purple and black.
Extended data:
Formaldehyde detection refers to the quantitative detection of formaldehyde contained in air, water, food, clothes, plates, leather, etc. through specific methods or instruments. White or non-ironing clothes, especially some jeans, underwear advertised as 100% crease-resistant and shrink-resistant or all-cotton non-ironing shirts are all shaped with glyoxal resin and all contain formaldehyde.
Indoor air environment formaldehyde content formaldehyde detection can be divided into:
1, AHMT spectrophotometry
The main methods of spectrophotometric determination are acetylacetone method, chromic acid method, MBTH method, magenta method, AHMT method and so on.
2. Acetylacetone method
The principle of acetylacetone method is that formaldehyde, acetylacetone and ammonia are used to generate yellow compound diacetyl dihydrodimethylpyridine, and then the yellow compound diacetyl dihydrodimethylpyridine is determined by spectrophotometry at 4 12nm.
The biggest advantages of this method are simple operation, stable performance, small error, and no interference from acetaldehyde. The chromogenic solution can exist stably for 65438±02hr；. . The disadvantage is that the sensitivity is low, and the minimum detection concentration is 0.25mg/L, which is only suitable for the determination of higher concentration formaldehyde. The disadvantage of this method is that the reaction is slow and takes about 60 minutes. . So what? There is interference in the determination (sodium bisulfite can be used as a protective agent to eliminate it). This method is very traditional and widely used.
3. Chromogenic acid method (CTA method)
Chromogenic acid method is also called chromic acid method. Formaldehyde can react with chromotropic acid (1, 8- dihydroxynaphthalene-3,6-disulfonic acid) in concentrated sulfuric acid solution to generate purple compounds. The maximum absorption wavelength of this compound is 580nm, which can be determined by spectrophotometry. Changing the concentration of chromotropic acid and adopting different sampling methods can meet the needs of formaldehyde detection with different concentrations.
4. Phenol reagent method
The principle of phenol reagent method is that formaldehyde reacts with phenol reagent to produce azine, which is oxidized by ferric ion in acidic solution to produce blue-green compounds. The color depth is directly proportional to the formaldehyde content, and the molar absorption coefficient ε of the compound at 630nm can reach 7.0× 104. This method is very sensitive to the determination of formaldehyde, and the minimum detection limit is 0.015 mg/L/L.
5.Paramagenta method
The principle of parafuchsin method is that sulfite ion and parafuchsin form purple complex in the presence of formaldehyde, and its maximum absorption peak is at 570nm, and the detection limit is 50 μ g/L. The advantage of this method is that it is simple and sensitive, and other aldehydes and phenols do not interfere with the determination. Disadvantages are fast fading, low sensitivity and easy to be affected by temperature. Using toxic mercury reagent, it takes at least 60min for the chromogenic compound to achieve stable absorption.
References:
Baidu encyclopedia-formaldehyde detection