| Launch：2022-07-04 |
In recent decades, the sugar industry has developed rapidly. At present, China has become an important sugar producer in the world. Sugarcane sugar production needs to be broken, pressed, settled, filtered and other steps to make a clear juice, and then through multi-effect evaporation to concentrate to form a syrup, and finally through the boiling sugar, crystallization and other steps to obtain raw sugar. In sugar production, the detection of sucrose concentration in sugar solutions is not only a test of the results of each step in the process, but also plays a very important role in the control process of production operations.
At present, the detection methods in the sugar process mainly include refractive index method, conductivity detection method, radio frequency detection method and so on. Now we test the sucrose concentration using Raman spectroscopy to see what results we get.
2.1 Experimental equipment
Portman1064 Raman spectrometer Liquid spectral measuring cell Probe holder Quartz cuvette
The equipment is set up as shown in the following figure.
2.2 Experimental environment
24℃
2.3 Experimental sample
Concentrations of 5%, 10%, 15%, 20%, 25% white sugar solution, solid white sugar and molasses.
2.4 Experimental steps
White sugar is laid flat on the aluminum foil, placed under the probe, and the probe position is adjusted so that the laser is focused on the sample surface for testing.
Different concentrations of sugar solutions and molasses are placed in the cuvette, and the cuvette is placed in the measuring cell, the Raman probe is inserted into the measuring cell, and the probe position is adjusted so that the laser is focused on the white sugar solution for testing.
Experiments measured different concentrations of white sugar solution, molasses, solid white sugar spectra as shown in the figure.
As can be seen from the figure, there are many clear sugar peaks, and the peak of water can be seen at 1291.93cm-1 (blue in the figure). Molasses can see obvious peaks, but may be due to the effect of fluorescence, so that the peak of molasses compared to white sugar and sugar solution has a certain deviation.
Since both molasses and sugar solution have obvious water peaks, we use the peak of water as a benchmark, calibrate and compare the sugar solution and molasses spectra, and obtain the following figure:
In five different concentrations of solutions, the more obvious 1168.42、1201.09、1260.21 cm-1 three peaks (as shown in the figure), with the concentration x, the peak strength is y, the peaks everywhere are linearly fitted, and it is found that there is a linear correlation between the concentration and the peak strength.
The figure shows that the intensity of each characteristic peak increases with the increase of the concentration of the sugar solution and has a clear linear trend.
In this experiment, PR1064 Raman spectrometer was used to detect different concentrations of sugar solution, solid white sugar and molasses, and the results showed that Raman spectroscopy can realize the detection of sugar. Since the intensity of the characteristic peak increases with the increase in the concentration of the sugar solution, and this change has good linearity, Raman spectroscopy can enable the monitoring of the concentration of the sugar solution.
