Luminol Chemiluminescence Method for Determination of Sulfite Residues in Food
Release time:
2021-11-01
The indicator of sulfite residues in food is one of the strict control indicators of the national quality inspection department. In the food processing process, human or non-human factors will cause the sulfite content in many foods to exceed national standards. How to control the sulfite content is a major problem faced by food production and processing enterprises and quality inspection agencies. In order to solve the problem of excessive sulfite residues in food, all food manufacturers and quality supervision departments must detect sulfite in food.
How to detect SO2 in food faster and effectively? This has to mention our chemiluminescence reagent luminol. Because sulfite has a very strong sensitizing effect on the luminol-air luminescence system, a chemiluminescence method for determining the residual amount of sulfite has been developed.
principle
Luminol is slowly oxidized in the air to excite luminescence. The luminescence intensity is basically stable for about 24S. At this time, the addition of trace sulfite makes the luminescence intensity of luminol sharply enhanced. After a maximum value, the luminescence intensity in the system The sulfite is gradually consumed by the reaction, and the luminescence intensity of luminol returns to the blank value. The area after the blank is deducted from the luminescence curve has a linear relationship with the amount of sulfite added. Based on this, the determination of the sulfite content can be established. method.
Concentration of luminol
When the concentration of luminol increases, the luminous value gradually increases to 1.0×10-mol/L, reaching the maximum value; the concentration continues to increase, the luminous intensity will increase, but its reproduction will be worse, so choose luminol The concentration is 1.0×10-3.
Influence of PH
When the pH is less than 8, the luminescence intensity of luminol is the same regardless of whether sulfite is added, and it is very weak. When the pH is greater than 8, the luminescence intensity of luminol in the air slowly increases, but when a trace amount of sulfite is added After the rapid increase, when the PH is approximately equal to 10.2, the difference between the two is the largest.
The effect of cobalt sulfate concentration
Cobalt sulfate is used as a catalyst for the Luminol-air-sulfite ion chemical reaction system, which helps the rapid progress of the chemical reaction and enhances the luminous intensity. It has also been found that the addition of cobalt sulfate can also inhibit the chemical reaction of the Luno-air system. Reduce the background luminescence, but adding too much under the experimental conditions will cause precipitation, which will affect the measurement. The experiment controls the concentration of cobalt sulfate at 3.6×10-4mol/L.
Healthy food is the guarantee for the body. We need to create more miracles with healthy bodies. What Lumino can do, why don't we choose to use it? Desheng is a manufacturer that develops and produces luminol. If you need it, don't miss it again.
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