The appearance of a general commodity can indeed reflect its quality, but the quality of the optical brightener is difficult to distinguish by the naked eye. So is there a way to detect the quality of optical brightener?Let us tell you 5 ways to test the quality of optical brighteners.

1. Ultraviolet lamp method

The whitening principle of the optical brighteners is to convert the invisible ultraviolet rays into blue light, thereby whitening and brightening the object, so it can be directly irradiated with the ultraviolet lamp to determine whether the fluorescent whitening agent is contained. This kind of ultraviolet lamp can illuminate the object to determine whether it contains optical brightener.

Limitations: The ultraviolet lamp method can only determine whether there is a problem, and cannot determine the content problem.

2. Ultraviolet spectrophotometry

Choose different solvents according to different Optical Brighteenrs. Because the fluorescent brightening agent has the ability to absorb ultraviolet light, the content of the fluorescent whitening agent is determined by measuring the amount of light absorbed and comparing with the standard curve. This is also the determination method in the national standard.

Limitations: UV spectrophotometry can determine the content, but cannot determine the specific model. The equipment of this method is relatively cheap, and the operation is simple. It is the method adopted by general enterprises. As long as you know the specific model of the fluorescent whitening agent purchased or produced, you can determine the amount of optical brighteners, and you will know this batch of fluorescent brightening agent's purity .

3. Molecular fluorescence spectrophotometry

The type and dosage of the optical brightener contained can be determined according to the light intensity and wavelength reflected by the measured substance. This method can determine the amount and type of the fluorescent whitening agent contained.

This method needs to separate the optical brighteners, that is, the fluorescent brightening agent needs to be separated from the product for measurement. It is a better method for detecting the type of fluorescent whitening agent used in the raw material.

4.high performance liquid chromatography

The high-performance liquid chromatography method uses an ultraviolet detector or a fluorescence detector to perform a quantitative determination based on the retention time and the chromatographic peak area after the injection solution is chromatographed.

Limitations: High performance liquid chromatography can accurately quantify specific fluorescent whitening agents, but the detection cost of this method is relatively high, and it is easy to be interfered by impurities according to the retention time and spectrum of the compound. Therefore, it is suitable for different types of optical brighteners. There are certain limitations in the qualitative judgment.

5. High performance liquid chromatography-mass spectrometry

The combination of high performance liquid chromatography and mass spectrometry can achieve good separation and accurate determination of fluorescent whitening agents. It uses retention time and characteristic ion ratio to perform qualitative and quantitative analysis of known targets, so the accuracy and sensitivity are higher.

Limitations: Due to the high cost of equipment and equipment, it is not conducive to the detection and monitoring of enterprise production, and has certain limitations in practical applications.

According to different testing requirements, the 1 UV lamp method can be used to determine the presence or absence, the 2 UV spectrophotometric method can be used to determine the quantity of the known model, and the 3 molecule fluorescence spectrophotometric method can be used to determine which type of fluorescent whitening agent and the amount. 4,5 The accuracy of the two methods is higher, and the equipment is expensive and not suitable for ordinary enterprises.