Azo dye column manufacturer states key points for textile azo dye detection-Chemical Instrument Network

　　Azo dye columnThe manufacturer introduces that azo is one of the mandatory testing items for environmental protection requirements, but not all azo dyes are banned. Only 24 aromatic amine azo dyes that will be released after reduction are banned, of which about 130 are prohibited. After long-term contact with human skin, clothing or other consumer goods dyed with banned azo dyes will mix with the components released during metabolic processes and undergo reduction reactions to form carcinogenic aromatic amine compounds. These compounds will be absorbed by the human body and undergo a series of activation reactions, causing structural and functional changes in the DNA of human cells, becoming a trigger for human diseases.

There are generally three methods for testing azo dyes: thin layer chromatography (TLC), gas chromatography and mass spectrometry (GC-MS), and liquid chromatography (HPLC). The standard stipulates that the tested product must not contain 23 types of azo dye intermediates. If one of them is detected, it is considered an unqualified product with a * of 30ppm.

Precautions for Inspection:

Before making samples, there needs to be a method development record, in other words, standard samples need to be used for spiked recovery and other projects to ensure the feasibility of the method.

2. The use of different diatomaceous earth columns has a significant impact on the recovery rate. Before replacing the diatomaceous earth columns and using different batches of diatomaceous earth columns, the recovery rate should be calculated.

The sealing of the reactor also has a significant impact on the recovery rate, ensuring strong sealing of the reactor.

During the concentration process, about 1mL must be left by rotary evaporation and must not be evaporated to dryness; The nitrogen blower needs to be slowly blown with nitrogen until it is almost dry, not completely dry, otherwise it will have a significant impact on the recovery rate.

5. Ensure the effectiveness of sodium hydrosulfite, which has a significant impact on the results. One simple way to assess effectiveness is to be able to reduce and fade non dispersed dye samples. Another method is to prepare a fresh colorless transparent solution that turns yellow immediately upon contact with air.

6. The time from cooling to column passing should be short, and a longer time can also affect the recovery rate.

7. The buffer solution needs to meet the requirements, with a pH of around 6.0, which also affects the recovery rate.

When making 4-aminoazobenzene, the concentration and volume of sodium hydrosulfite solution added should be accurate, as it has a significant impact on the recovery rate.