Alkali blue 6B (C.I. 42765), 25 g

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The content of colourants is not specified for many products for various reasons:

1. complex composition: colourants are often mixtures of several components that may be present in different ratios. These compositions can vary, which makes it difficult to state an exact content.

2. application focus: In many applications, especially in the textile and food industries, the exact concentration of a dye is less relevant than its colouring power or its ability to achieve a certain colour. Here, the colour strength or the ability to impart colour is the most important criterion.

3. standardisation: Many dyes are traded according to certain standards (e.g. C.I. numbers) which guarantee a certain quality and colouring. These standards often make an exact specification of content superfluous, as users know that the colourant has the desired properties.

4. manufacturing processes: The manufacturing process of colourants can lead to natural variations in content. Instead of specifying an exact content, quality control is often carried out to ensure that the colourant is within an acceptable range.

5. Regulatory aspects: In some cases, regulatory requirements may not require the manufacturer to declare the exact content as long as the colourant is safe and effective for the intended purpose.

6. cost reasons: An exact determination of the content often requires complex analytical procedures that could increase production costs. Therefore, some manufacturers do not provide this additional information in order to save costs.

In summary, it can be said that the content of colourants is often not specified because other quality criteria are in the foreground and the exact concentration is not decisive for many applications.

Acid Value Determination

The acid number characterises the acidic components of the fats. For this purpose, the sample is dissolved in a solvent and titrated against phenolphthalein with potassium hydroxide solution. Only free fatty acids are recorded. The fatty acids bound in the glycerides are not determined.

The saponification value denotes the amount of potassium hydroxide required to neutralise free fatty acids and saponify bound fatty acids. The lower the average molar mass of the fat, the higher the saponification value. The sample is heated under reflux in a defined quantity of ethanolic potassium hydroxide solution and the non-used alkaline solution is titrated with hydrochloric acid.

Hydroxyl Value

The hydroxyl value is a measure of the hydroxy group content of organic materials such as paints, resins, polystyrenes, solvents and lipids. It represents the amount in milligrams of potassium hydroxide required to neutralise the quantity of acetic acid that combines on acetylation of one gram of the substance being tested.