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English| Launch：2022-05-19 |
In the hot summer, there is only the tail left, presumably the little friends will inevitably have a dry mouth when they go out in the summer. At this time, compared with a wide variety of sugar water drinks, some small partners will choose healthy and additive-free bottled water to quench their thirst.
However, don't underestimate this seemingly transparent bottled water, the appearance is bland, in fact, there is a lot of elegance inside. Usually, our common bottled water is divided into four types: pure water, mineral water, mineral water and natural water. What is the difference between these four kinds of water, for everyone to introduce one by one.
Purified water is best understood and refers to pure, clean water that does not contain impurities or bacteria, including organic contaminants, inorganic salts, any additives and various types of impurities. However, while filtering out these impurities, it will also filter out the dissolved minerals and trace elements in the water. So there was a rumor before: drinking pure water all year round will lead to nutrient loss and so on. Therefore, many manufacturers have introduced so-called mineral water. In essence, it is generally made of urban tap water as raw water, which is processed by pure purification, added minerals, and filled after sterilization. However, the minerals added by mineral water are of a chaotic variety, and the most added are generally magnesium sulfate and potassium chloride. At present, there is no unified national standard for quality, which is mainly added by the industry in accordance with the provisions and limits of the "Sanitary Standards for the Use of Food Additives" (GB2760-2007). The mineral water is extracted from the depths of the underground naturally gushing out or artificially exposed, unpolluted underground mineral water, after a minimum of disinfection and filtration treatment, not only removes the very few impurities and harmful substances in the raw water, but also preserves the minerals and trace elements in the raw water. Because the intake of minerals and trace elements has certain benefits for the body, it has also become the most familiar bottled water.
The last thing left is natural water, which actually contains mineral water, but also drinking water from rivers, glaciers, lakes, mountain springs and other surface water sources. Its treatment process is the same as that of mineral water, which requires a limited treatment process to remove impurities and harmful substances, and retain minerals and trace elements. Therefore, the water source requirements of natural water are quite demanding, which is also the reason for the high price of those mountain springs in supermarkets.
So the question is, what is the way to determine the amount of minerals in bottled water, other than looking at the label on the bottle? For example, Oceanhood has a more professional method-Raman spectroscopy to determine.
Raman spectroscopy reflects information about the vibration and rotational energy levels of molecules. The water molecule (H2O) is composed of 1 oxygen atom and 2 hydrogen atoms, and is a nonlinear molecule with an angle of 105° between O-H bonds. Its standard Raman spectra (purified water) are shown in the figure below. The vibration pattern of the water molecules manifests as two characteristic peaks, located near 1626 cm-1 and 3225 cm-1, respectively.
Because the minerals and trace elements contained in drinking water will affect the structure of water molecules, such as: calcium, sodium, potassium, magnesium plasma charge is large, small size, will strengthen the structure of water molecules, thereby weakening the vibration energy of molecules. The intensity of the characteristic peaks on the Raman spectrum weakens.
So we used the Portman 532nm Raman Spectrometer of Oceanhood to collect four samples: distilled water, bottled pure water, laboratory filtered water and tap water. Their spectral information was measured separately, as shown in the figure below.
Raman spectra of four water samples
From this figure, it can be concluded that the mineral content contained in these four kinds of water is in order from less to more: distilled water< filtered water< pure water< tap water. Distilled water has less mineral content, while bottled purified water has a similar mineral content with laboratory filtered water, and tap water is more mineral content. But in fact, the chloride ions and other particles in tap water may also affect the Raman spectra, which also shows that there are more impurities in tap water. It can be seen that Raman spectroscopy can not only be used in the fields of material science and life science on the tall, but also reflect its application value in our daily lives. However, in the end to remind the small partners, usually the main purpose of drinking water is to replenish water, and the absorption of other minerals is not the main purpose, the amount of supplementation is also very limited, do not deliberately pursue.
