Détails de la société
Shijiazhuang Standard Imp&exp Co.,Ltd.
As a very important feed additive, choline chloride has received more and more attention. So how do we detect the quality of it? At present, there are Apparent inspection method, Non-aqueous titration, the silver content method, Kjeldahl method, Sodium tetraphenylborate gravimetric method, Rayleigh's salt (ammonium diaminotetrathiocyanate) Gravimetric method, Ion Chromatography, etc., and I will introduce it to you.
1. Apparent inspection method: After taking the powdery sample or product, first observe carefully to see if it is uniform, whether there is “white frost” on the particles or white powder on the bottom after shaking, and whether it is placed in the air Hygroscopic phenomena, etc., normal samples should not appear obvious "white frost" and "white powder", and less than half an hour, there will be hygroscopic phenomenon. 2. HG2941-1999 Non-aqueous titration of perchloric acid in the national standard: Since the incorporation of ammonium salt, trimethylamine hydrochloride, and hexamethylenetetramine can also react with perchloric acid, the test method is not suitable for choline chloride. Specificity can not play the role of authenticity, to give adulterate opportunities. However, if some manufacturers understand their own production procedures and know that they are not adulterated, they can use the non-aqueous titration method to carry out the daily quality control of the product. As long as the production process is well controlled, trimethylamine does not exceed the standard. It does not produce inconsistency when measured by different methods. Example AkzoNobel Chemical Co., Ltd. strictly according to European standards and "feed = food" concept to produce choline chloride, no adulteration, so the daily internal quality control basically non-aqueous titration method. 3. In the HG2941-1999 national standard appendix, the silver content method: Since the method is based on the measurement of chloride ions, the trimethylamine hydrochloride, which is an artificial residue, is incorporated into the soluble chloride in choline chloride or chemically synthesized. The result is too high to achieve real purpose. 4. Kjeldahl method: The residue of trimethylamine hydrochloride, which is an intermediate product in which a nitrogen-containing compound or choline chloride is synthesized, can make the detection result high, achieving the purpose of doping and making it fake. 5. Sodium tetraphenylborate gravimetric method: Pb2+, Ag+, potassium salts, ammonium salts, organic amines, alkaloids, and other quaternary ammonium salt compounds can all interfere with the precipitation of sodium tetraphenylborate, resulting in high results and should also cause We attach great importance to it. 6. Rayleigh's salt (ammonium diaminotetrathiocyanate) Gravimetric method: Since hexamethylenetetramine (Urotropine) is a quaternary ammonium salt, it cannot be decomposed by alkali, and it reacts with Rayleigh's salt to generate pink precipitate. , making the measurement result high and adulterated. At this point, we must use acid, alkali hydrolysis Reiz salt weight method, that is, the sample was first added 2mol/L sulfuric acid solution 10ml boiled for 30min, after the decomposition of hexamethylenetetramine, and then add alkali boiling deammonia, about PH6 The Reynolds salt reaction, the formation of a pink precipitate can be detected by the gravimetric method of choline chloride content. Although the Rayleigh salt gravimetric method is more complex than the method in HG2941-1999, it is feasible for some feed mills. Therefore, the new standard lists this method as a conventional quantitative method. 7. Ion Chromatography: Ions are used to separate ions with different charges, ionic radii, and structure, so that, like other chromatographic methods, it is not ruled that different compounds have the same or similar retention times as choline chloride. However, under the specified experimental conditions, the possibility is minimal. Therefore, the new standard uses ion chromatography as the arbitration method. However, because the chromatograph is expensive, most feed mills are temporarily difficult to configure, and only a few national-level testing centers are available, so the popularity is very narrow. Before the new standard was introduced, the choline market was more confusing and counterfeit goods could not be prevented. The lack of choline would cause the animal to slow down and seriously affect the quality of the feed. Therefore, the purchase of choline chloride from the regular manufacturers is still a good plan.
Copyright © 2020 Shijiazhuang Standard Imp&exp Co.,Ltd.Tous droits réservés.