1. Oven method

1. Principle

: Dry a sample of a certain quality at a certain temperature under normal pressure for a certain period of time, and express the solid content as a percentage of the sample mass after heating to the sample mass before heating.

2. Determination of step aggregation

① Take three weighing bottles, dry them in an oven at (105±2)°C for 1.5 hours, then cool them in a desiccator for 30 minutes and weigh them, record it as m1.

② Weigh 1~2g (accurate to 0.0001g) sample into a dried weighing bottle, record it as m.

③ Gently turn the weighing bottle to make the sample evenly distributed on the bottom of the weighing bottle, slightly open the cover of the weighing bottle, place it in an oven at (105±2) ℃, turn on the blower, and dry the bottle for 3 hours. Cover it tightly, put it in a desiccator to cool for 30 minutes, weigh it, and record it as m2.

3. Calculation of results

The solid content of the sample is expressed in mass fraction X, and the value is expressed in (%), calculated according to formula (1):

X=(m2-m1)/m×100% (1)

In the formula:

m - the numerical value of the sample mass. The unit is grams (g);

m1 - the numerical value of the mass of the sample. The unit is grams (g);

m2——the value of the weight of the weighing bottle and the sample after drying. The unit is grams (g).

Take the arithmetic mean value of the two parallel measurements, and round it up to 0.1% according to GB/T8170-2008, which is the measurement result, and the difference between the two parallel measurement results is not more than 0.3%.

2. Sugar meter method

1. Principle:

The sugar content of the solution measured by the principle of refraction has a certain proportional relationship with its solid content. By measuring the sugar content of the solution, the solid content of the sample can be converted according to a certain proportional coefficient.

2. Determination steps:

The test should be carried out at room temperature, and the sample should be equilibrated to room temperature before measurement.

① Clean the surface of the prism of the sugar meter, drop about 0.3mL of water on the surface, and adjust to zero according to the operating instructions of the sugar meter.

② Discard the water on the brix meter, dry the prism, drop about 0.3mL of sample on its surface, measure the brix content of the sample according to the brix meter operating instructions, and record it as the sample brix content A until the two readings are stable.

③ Calculate the solid content of the sample according to the proportional coefficient n between the solid content and the sugar content obtained from data accumulation.

Note: Because this method is tested by using the principle of refraction, do not use it for the test of samples that are difficult to wash with water, otherwise the surface of the prism will be polluted and the test will be inaccurate.

3. Calculation of results

The solid content of the sample is expressed in mass fraction X, and the value is expressed in (%), calculated according to formula (2):

X = n×A ---------- (2)

In the formula:

n——Conversion coefficient between solid content and sugar content

A - the sugar content of the sample, %

3. Rapid solid content tester method

This method is faster than the oven method, and more accurate than the sugar meter test. For the specific method, please refer to the manual of the rapid solid content tester.