GB/T 5918-2008Determination of mixing homogeneity for feed products (English PDF)

3.1 Principle

Chlorine ion selective electrode by selective electrode potential response to chlorine ions in solution to determine the content of chlorine ions to the same batch

Different samples of feed differentially chloride ion content to reflect the degree of homogeneity of the feed.

3.2 Reagents

The following reagents, unless otherwise stated, were of analytical grade. Distilled water, in line with the provisions of three water GB/T 6682's.

3.2.1 nitric acid solution

concentration of about 0.5mol/L, was diluted with water to absorb nitric acid 35mL 1000mL.

3.2.2 Potassium nitrate solution

concentration of about 2.5mol/L, weighed 252.75g potassium nitrate in the beaker, add water, heat gently to dissolve, diluted with water to

1000mL.

3.2.3 Chloride standard solution

Weigh learn 550 °C sodium chloride 8.2440g burning 1h after cooling in a beaker, add water, heat gently to dissolve,

Into 1000mL volumetric flask, dilute to the mark, shake, chlorine ions in solution 5mg/mL.

3.3 Instrument

3.3.1

chlorine ion selective electrode.

3.3.2

double salt bridge SCE.

3.3.3 pH meter or potentiometer

accuracy 0.2mV.

3.3.4

magnetic stirrer.

3.3.5 beaker

100mL, 250mL.

3.3.6 pipette

1mL, 5mL, 10mL.

3.3.7 flask

50mL.

3.3.8 Analytical Balance

a sense of the amount of 0.0001g.

3.4 Sampling

3.4.1

Law required samples should be taken separately.

3.4.2

Each batch of feed products extracted 10 representative of the original sample, sampling of each sample is about 200g. Determine the sampling points should be

Consider the depth representative of all places the number of bags or stream, but each sample should concentrate a little sampling. It does not allow any sampling flip

Or mixed.

3.5 Sample Preparation

Each sample was thoroughly mixed in a laboratory. Feed pellet sample to be pulverized by 1.40mm sieve.