Accurately understand the true content of propionic acid-based mildew inhibitors and effectively select and use mould inhibitors

Propionic acid-based mildew inhibitors play a very important role in extending the shelf life of feed due to their strong penetration ability, no dead corners for mildew prevention, and high cost-effectiveness, and are widely recognized by feed companies. The propionic acid-based mold inhibitors on the market, whether sodium propionate + propionic acid or ammonium propionate + propionic acid, all achieve mildew prevention through propionic acid, so the total propionic acid content is one of the most basic and effective indicators for measuring the mildew prevention effect of propionic acid-based mold inhibitors. There is no unified national testing standard for the detection of active ingredients in feed mould inhibitor products. Mold inhibitor companies have made corresponding corporate standards based on their own company’s testing level and understanding of mould inhibitors, and their testing methods vary greatly. Combining the corporate standards of various companies, the following methods for detecting propionic acid in propionic acid-based mould inhibitor products are summarized:

1. Propionate (sodium or ammonium)

1）. Perchloric acid non-aqueous titration:
The test is for organic acid salts or other substances, and the final calculation is based on the molecular weight of propionate; among the common raw materials of mold inhibitors: ammonium formate, calcium formate, sodium diacetate, calcium propionate, sodium propionate, ammonium propionate, sodium benzoate, potassium sorbate can all be tested by this method, but the final calculation is based on their corresponding molecular weight;

2）. Kjeldahl nitrogen determination method:
The test is for nitrogen in ammonium propionate, and then converted to ammonium propionate. This method mainly requires that the raw materials must contain nitrogen. Common raw materials include: ammonium formate and ammonium propionate.

2. Total propionic acid

1）. Acid-base titration (products without salt):
Titrate the acidic substances in the product, and calculate according to the molecular weight of propionic acid. Common acidic substances in mould inhibitors are: propionic acid, formic acid, acetic acid, and benzoic acid;

2）. High-performance liquid chromatography:
All substances containing propionate radicals in the product are detected, that is, the substances that ultimately play a mildew-proof role; Common substances containing propionate radicals in mildew inhibitors are: propionic acid, sodium propionate, ammonium propionate, and calcium propionate;

3）. Acid-base titration + perchloric acid non-aqueous titration:
Total acidic substances calculated by propionic acid + organic acid salt substances calculated by propionate salt;

4）. High-performance liquid chromatography + perchloric acid non-aqueous titration:
All substances containing propionate radicals are detected by high-performance liquid chromatography, calculated by propionic acid, and then organic acid salt substances calculated by propionate salt are added.

3. Free propionic acid (or propionic acid)

1）. Acid-base titration method:
It detects all acidic substances in the product (including propionic acid, formic acid, acetic acid, phosphoric acid, etc.), and calculates according to the molecular weight of propionic acid;

2）. High-performance liquid chromatography method 1:
First, the content of propionate is detected by perchloric acid non-aqueous titration, and then the content of propionic acid in propionate is calculated as X1, and the total propionic acid content X2 detected by high-performance liquid chromatography is calculated to calculate the propionic acid content X=X2-X1;

3）. High-performance liquid chromatography method 2:
The content of propionate in the standard is converted to its propionic acid content X3, and the total propionic acid content X2 in the product is detected by high-performance liquid chromatography, and the propionic acid content X=X2-X3 is calculated;

4）. High-performance liquid chromatography method:
All substances containing propionate in the product are detected.

When choosing a mold inhibitor, according to the nature of our product, after determining the combination of mould inhibitor ingredients, for a specific product, we need to pay attention not only to its labeled content, but also to its detection method! !