Water is a laboratory essential.
It is often overlooked but plays a crucial role in various processes.
During automated biochemical analysis, pure water serves as a carrier or medium for chemical reactions, a diluent or solvent for samples and reagents, and a cleaning solution for instruments.
It also participates directly in reactions as a reagent.
The entire testing process relies heavily on the purity of the water used.
This purity level significantly affects the reliability of the test results.
Currently, most laboratories use reverse osmosis central pure water systems to ensure high-quality water supply.
Ruifeng has analyzed the workflow of these systems and identified several common issues related to water purity, their causes, and their impact on automatic biochemical analyzers.
1. Pure Water System Workflow and Influencing Factors
1.1 Raw Water Pretreatment
Raw water refers to tap water entering the laboratory. The pretreatment stage aims to remove most impurities from this water before further purification.
Pretreatment typically includes:
- Deep filtration to remove large particles like sediment;
- Activated carbon filtration to eliminate organic matter and residual chlorine;
- Softening filters to reduce calcium and magnesium ion concentration, lowering water hardness.
The quality of the incoming tap water and the lifespan of the pretreatment components significantly affect system performance.
1.2 Reverse Osmosis (RO) Treatment
Reverse osmosis membranes are highly effective at removing ions and impurities, with a typical removal rate exceeding 95%.
Factors affecting RO efficiency include:
- Inlet water pressure: insufficient pressure reduces water output;
- System maintenance: regular backwashing and proper settings are critical for optimal operation.
1.3 Deionization Process
Water treated by RO may still contain some ions, so further deionization is necessary to achieve first-grade pure water (resistivity ≥10 MΩ·cm).
Ion exchange resins are commonly used, where cation and anion resins work together to remove remaining impurities.
Factors influencing this step include resin quality, connection configuration (e.g., double bed, mixed bed), and the purity of the third-grade water.
2. Impurity Components in Unqualified Pure Water
Impurities in unqualified water can come from tap water or the purification system itself. Common impurities include:
- Ions such as Naâº, Ca²âº, Mg²âº, Fe³âº, Cu²âº, etc., and anions like Clâ», NO₃â», SO₄²â»;
- Organic substances like pesticides, alcohols, and esters;
- Particulates such as rust and sediment;
- Microorganisms and dissolved gases like COâ‚‚, Oâ‚‚, and Hâ‚‚S.
3. Impact of Different Impurities on Biochemical Analyzers
3.1 Ions
High levels of metal ions can interfere with enzyme activity, leading to inaccurate measurements. For example, Mg²⺠acts as an activator for many enzymes, while heavy metals may inhibit them.
3.2 Organic Substances
These can increase background readings and accelerate wear on piping and cuvettes, reducing instrument lifespan.
3.3 Particulate Matter
Particles can cause blockages and increase absorbance, affecting test accuracy.
3.4 Microorganisms
Contaminated water can lead to microbial growth inside the analyzer, causing blockages and false readings.
3.5 Dissolved Gases
Gases like COâ‚‚ can lower water pH, affecting pH-sensitive tests and redox-related assays.
4. Discussion
There are two main types of automated pure water systems in labs today:
- Large distiller systems, which are outdated due to low efficiency and limited application;
- Reverse osmosis central systems that combine mechanical filtration, activated carbon, RO membranes, and ion exchange, offering high efficiency and wide usage.
Common indicators for evaluating water quality include resistivity, total organic carbon, particle count, and pyrogen content. Regular monitoring and maintenance are essential to ensure consistent water quality and avoid contamination.
5. Recommendations
- Implement strict quality control and regularly measure key parameters like resistivity;
- Enhance awareness of water quality importance to prevent operational errors;
- Control open storage tanks to prevent secondary pollution;
- Understand component lifespans and maintenance procedures to prolong system life;
- Assess local water conditions and consider installing advanced pretreatment systems if needed.
Pond Filtration Pumps,Canister Filter,Frequency Outside Filter,Garden Pond Pressure Filter
Sensen Group Co., Ltd.  , https://www.sunsunglobal.com