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Protein powder is derived from plant soybeans or milk, rich in protein with high nutrition, can be quickly absorbed and utilized by the human body, enhancing one's own physique. The common trace elements in protein powder include Cu, Fe, Zn, Mn, Na, K, Ca, Mg, Cr, etc., among which Na and K are relatively high content of macro elements, which play an important role in the stability of osmotic pressure in the homeostasis of the human body.

Therefore, this article shares how to use the Welso microwave digestion system to digest protein powder?

Since the organic components of protein powder mainly include soy protein, whey protein, pea protein, methionine, etc., the basic elements of these components are C, N, O, so usually more gas is produced during microwave digestion, and HNO3, HNO3/H2O2, HNO3/HCl are commonly used as digestants.

Experiment preparation

Sample name: Protein powder

Digestion reagent: Nitric Acid AR

Instrument used: Welso WMD600 closed microwave digestion system

▼ Experimental Procedure

●Weigh 0.2g of the sample (accurate to 0.1mg), place it in the microwave digestion inner vessel, add 9 mL of nitric acid to the sample, mix well, and let the sample and wait for 10 minutes.

●Sealed the cap, loaded into the microwave digestion instrument, microwave digestion according to the digestion methods table.

●After the digestion is complete and the cooling is completed, transfer the digestion vessel to the fume hood.

●Unscrew the outer vessel of the digestion vessel, slowly relieve the pressure in multiple times, and take out and open the inner vessel.

Sample Digestion Program

▼Result

The digested protein powder is light yellow and transparent (as shown in the figure below), which is an effective and reasonable digestion method, and the sealing system avoids reagent volatilization and ensures the recovery of elemental analysis.

Importance of Sample Preparation

The composition of each sample is very complex, some samples contain a large number of organic compounds or even polymer compounds, they either wrap the components to be measured, or adsorb the components to be measured, or combine with the components to be measured, some samples often contain a large number of other components similar to the properties of the components to be measured or directly react with the components to be measured, etc., . So many samples can not be directly used for detection and analysis, and the appropriate method should be selected to pre-treat the samples according to the nature of the components to be measured and the interfering components before analysis. This pretreatment measure to eliminate or reduce interfering factors is called pretreatment of sample analysis, and sample pretreatment is essential for later analysis, and it can be said that pretreatment determines the outcome of the analytical test.

Why is microwave digestion used?

This is related to the principle of microwave digestion, the use of microwave radiation to heat the sample, the sample in the high pressure, high temperature, high acid environment, quickly converted into solution or gas, the traditional digestion method requires a long time and high temperature, and the microwave digestion instrument can complete the sample digestion in only 20-40 minutes, and can adjust the temperature and pressure according to the specific experimental situation. The microwave digester heats up evenly and has less error than the contagion method, which provides a clear, accurate sample for subsequent analysis, thus reducing interference during reanalysis.

In terms of saving time and cost, the advantages of microwave digestion are obviously more significant, and when working with large quantities of samples, microwave digestion is the best choice!