Water

Types of Water Used in the Laboratory 

The water we use in laboratories is generally consumed on a daily basis. In recent years, it has been realized that there is a need for water of different qualities for many applications in parallel with technological developments, and systems have been developed to meet these needs.

The use of laboratory waters is shaped according to the nature of the analysis to be performed. Systems should be selected to meet these requirements. Using the right quality water is very important to get the right result. However, a system that provides optimum conditions that meet the needs is very important in terms of costs.

Water quality is also very important for analysis safety and reproducibility. For this reason, water quality levels are specified in the standards according to the nature of the analysis to be made. In studies, analyses should be carried out taking into account the levels in these standards.

Generally laboratory waters; Tap water is classified in 4 groups as Type 1, Type 2, and Type 3 water.

Tap water

Tap water is water that is taken directly from the network and whose organic, inorganic, and microbial parameters are unknown. This water is used for general cleaning works, and for washing glass and plastic materials. However, when used for washing glass and plastic materials, the final rinse water should be chosen as Deionized Water.

Type 3 Water (Basic Grade Water / Primary Grade Water)

Type 3 water, commonly referred to as instrument feed water, is the lowest quality and lowest cost laboratory water production technique. Type 3 water is used for pre-treatment to produce ultraDeionized Water.

It is produced using reverse osmosis (RO), which removes about 90-99% of contaminants. In the RO process, water is forced to pass through the pores on the membranes under high pressure. During this process, while water molecules and some inorganic molecules can pass through the pores, most of the substances in the water cannot pass through these pores and are thrown out as concentrated water. Feed water temperature, pressure, and physical condition of the RO membrane are parameters that affect membrane permeability rates. Therefore, RO water cannot be classified as special.

It is recommended to use Type 3 water in laboratory dishwashers, damp rooms, and autoclaves.

Type 2 Water (General Laboratory Grade Water/ Deionized Water)

Type 2 water is also known as “Deionized Water” and provides pre-treated water to feed the Type 1 UltraDeionized Water system. Type 2 water, also known as general laboratory-grade water, is produced by a combination of reverse osmosis (RO) and additional technology such as ion exchange or electric ion exchange (EDI). The deionization process is applied to the water obtained with RO using synthetic resins and ions are removed.

Ions are electrically charged atoms or molecules with a net negative or positive charge found in water. In washing processes or for many applications that use water as a solvent, these ions are considered impurities and must be removed from the water. Ions with a positive charge are called “Cations” and ions with a negative charge are called “Anions”. Ion exchange resins are used to replace unwanted cations and anions with hydrogen and hydroxyl, respectively, to form deionized purified water (H2O).

Generally, the following ions are found in the mains water.

In the ion exchange process, the water is subjected to a series of chemical reactions by interacting with the ion exchange resin as it passes through the cartridges that provide the ion exchange, thus removing all the mineral salts dissolved in the water.

As a result, deionized water with a conductivity of 1-15MΩ-cm is obtained as a result of the reverse osmosis process and ion removal process in Type 2 water system. Deionized water can also be called demineralized water.

In laboratories, the concepts of Deionized Water (deionized) and distilled water are used as if they are the same. In fact, Type 2 water and distilled water are produced by different methods. While distilled water is obtained by heating and condensing water, Type 2 Deionized Water is obtained by RO and deionization processes. Therefore, there are differences in their content and purpose of use. Depending on the source of the water, distilled water may be purer than Type 2 distilled water, but that doesn't mean it's better. There are advantages and disadvantages in both waters, especially when it comes to cost and efficiency. This should be determined according to the procedure to be applied.

Type 2 water can generally be used for micro preparation, microbiology media preparation, biochemistry analyzers in the diagnostic industry, and the preparation of reagents, and buffers for chemistry analysis.

Type 1 Water (UltraDeionized Water/UltraDeionized Water)

Type I water, the purest grade of laboratory water, is also called ultraDeionized Water. With a resistance of 18.2 MΩ-cm at 25°C, ultrapure (Type 1) water is a necessity for analytical laboratories.

Such waters may contain organic pollutants, endotoxins, and nucleases that do not affect the resistance and cannot be measured on the resistance value. Additional equipment should be used to remove them from the environment. They can have a UV lamp emitting 185 nm and 254 nm light to destroy bacteria and organic matter. Water passes through UV light, and as it passes, the light damages the genetic molecule needed for the reproductive functions of microorganisms, preventing them from multiplying. Thus, infection is prevented.

If it is desired to obtain DNase/RNase-free water, a system with ultrafiltration (UF) can be used. The ultrafiltration process is provided by using size exclusion technology. In systems used to obtain ultraDeionized Water, additional equipment can be used depending on the application.

Type I water; It is recommended for extremely critical applications such as HPLC, mass spectrometry, trace element analysis, pyrogen-sensitive applications, molecular biology applications, electrochemistry, electrophoresis, cell and tissue culture, and biotechnology.

As a result; each type of water is obtained by subjecting it to a different process. For this reason, the application you will make for water selection in the laboratory is very important. You should choose the most suitable system by determining your needs such as cost, efficiency, and repeatability.

Technical features required for each water grade; It is specified in international standards such as the International Organization for Standardization (ISO), American Section of the International Association for Testing Materials (ASTM), and the Clinical & Laboratory Standards Institute (CLSI). Also, in drug and biopharmaceutical applications, the United States Pharmacopeia (USP), European Pharmacopoeia (EP), Japanese Pharmacopoeia (JP), and British Pharmacopoeia (BP) should be referenced.

Deionized Water Properties

The most important feature of Deionized Water is that it is completely free of all organic and inorganic components and minerals. Purified water obtained by the deionized, distilled, or demineralized method is expected to reach the following values.

What is Deionized Water?

Water that is completely free of organic and inorganic substances is called Deionized Water, demineralized water, or deionized water. Deionized Water, which is generally used in industrial processes and laboratories, is also called deionized water, demineralized water, or distilled water. Another feature of Deionized Water is that it is non-conductive. In this respect, it is used in many areas in the industry.

Where is Deionized Water used?

Deionized Water is used in every field of industry.

In any laboratory device

Coating, painting industry,

In mold washing separation work,

In the metal sector,

In the glass industry,

In the plastics industry,

In steam production,

In the chemical industry,

In the electronics industry,

In the food industry,

Deionized Water has no taste, smell, color or conductivity, so it has no effect on the raw material it comes into contact with. For example, if you are manufacturing perfume, the smell of your perfume is not affected by the water in it and remains pure. Or lime etc. in the product you are washing and rinsing. Stains do not occur. In short, Deionized Water helps to maintain the standard of the product you manufacture.