Determination of Alcohol Content in Liquor by Refractive Index Method

Experimental principle:

The linear relationship between the alcohol content of liquor was determined by the principle of refractive index method to determine the alcohol concentration.

equipment:

ATAGO RX-5000 É‘ automatic Abbe refractometer; anhydrous alcohol; pipetting gun (range 1-10 ml).

RX-5000 É‘ fully automatic Abbe refractometer

Experimental steps:

Take 9 clean colorimetric tubes, add 1, 2, 3, 4, 5, 6, 7, 8, 9 ml of absolute ethanol, and dilute to 10 ml with water. The alcohol content of the standard sequence is 10 respectively. %-90%. Shake well by hand. To be tested.

A drop of pipette was used to take 1 drop of the detection window of the atago refractometer, and the refractive index at 20 degrees Celsius was measured. The results are as follows:

Table 1: Experimental data

The picture shows the linear relationship between alcohol content and refractive index.

experiment analysis:

As shown in the figure: Although the result of the test is not linear, there is a logarithmic correlation, and the square of the correlation coefficient reaches 0.9831. The sample tested for liquor had a degree of 45 degrees and a refractive index of 1.35652. We can find that the wine's refractive index is between 40% and 50%, which is consistent with the range of liquor indication. At this time, a quantitative problem is involved. The direct logarithm evaluation is very cumbersome, and 40% to 50% can be approximated as a straight line, which is in line with the linear relationship.

Substituting the refractive index of 1.35652 into the formula for calculation, the calculated result is 0.4505, and the conversion is 45.05%, which proves that the selected method is correct and can detect the alcohol content in the liquor. Measuring the alcohol content of liquor with an atago refractometer is an effective method for detection.

Experimental results:

The ATAGO automatic Abbe refractometer can quickly measure and measure the alcohol content of liquor. The operation method is simple and fast, and the measurement result is accurate. It is a new and effective detection method.