GB/T 22427.4-2008Starch - Determination of spot (English PDF)

2.1

Under specified conditions, it was visually observed variegated point.

Principle 3

By visual observation of the sample, read out the number of spots.

4.1 transparent plate

engraved with 10 square grid (1cm × 1cm) of a colorless transparent plate. Clean, non-polluting.

4.2 tablet

white, clean, non-polluting, can be uniformly distributed samples.

5.1 Sample preparation

Samples should be thoroughly mixed.

5.2 said sample

Weigh the sample (5.1) 10g, evenly distributed in the plate (4.2) on.

5.3 Counting

The transparent plate (4.1) to cover the sample has been evenly distributed, and gently flatten. In good light, the distance between the eye and the transparent plate holding

30cm, the sample was observed with the naked eye spots and count, write down the total number of spots in the 10 spaces of the sample.

Note. The uncorrected visual acuity or corrected visual acuity analyst should be above 1.0.

5.4

Determination of the number of

Parallel experiments should be carried out.

6.1 Calculation Method

Results in the number of spots per square centimeter, said, see (1).

X = C10 (1)

Where.

--- X-spot sample, in units of per square centimeter (number/cm2);

The total number of C --- 10 spots inner spaces, is detected.

Parallel experiments take the arithmetic mean of the result, the result rounded to one significant figure.