Water quality and Glass wares

Importance of Water Quality and Glass Wares in Clinical Laboratory:

Maintaining water quality in the clinical laboratory is essential for accurate and reliable test results, proper functioning of equipment and to ensure the best possible patient care. Water quality importance can be explained below details:

• 1. Universal Solvent: Water is an excellent solvent. It can dissolve several chemicals. It is required for chemical reactions and biological processes.

• 2. Accuracy of tests: It is used in several laboratory procedures such as reagent preparation, sample dilution, etc. Pure water is free from impurities. It does not interfere with laboratory tests. Water such as distilled water leads to accurate diagnosis and tests.

• 3. Reagent preparation: Reagents require distilled water to ensure the effectiveness and quality of the reagent. Normal water may contain contaminants that affect the composition of reagents and their effectiveness.

• 4. Equipment maintenance: High-quality water shall be required to clean laboratory equipment. This cleaning prevents contamination. It also ensures accurate results of tests.

• 5. Cohesion and Adhesion: Water molecules exhibit cohesion (stick to each other) and adhesion (stick to other surfaces). These properties contribute to capillary action and the formation of surface tension

• 6. Reproducibility: Quality water ensures reproducibility of experiments and tests.

• 7. High Heat Capacity: Water has a high specific heat capacity. It can absorb and retain heat. This property regulates temperatures in the environment and in living organisms.

• 8. Chemical Neutrality: Pure water has a neutral pH (around 7). This makes it a suitable medium for various chemical reactions.

• 9. Three States: Water exists in three states—solid (ice), liquid (water), and gas (water vapor) under normal environmental conditions. This makes it useful in different laboratory processes.

• 10. Good Conductivity: Water is a good conductor of electricity, to some extent, due to the presence of ions. This property is essential in various physiological processes within living organisms.

Thus, water quality directly affects the accuracy of the report, reliability of the report, and validity of diagnostic tests.

Importance of Glass wares in the clinical laboratory:

Glassware is transparent, inert, and easy to sterilize. Thus they are ideal for measuring liquids, preparing solutions, and conducting experiments. The following are the importance of glass wares in clinical laboratories:

• 1. Physical properties: Glass wares are transparent and nonreactive to most of the reagents and temperature changes. Thus it is most suitable for liquids accurately and performing chemical reactions.

• 2. Shapes and sizes: Glass wares are available in different shapes and sizes. Thus, they are most suitable for clinical laboratories.

• 3. Accuracy: Glass wares measure liquid accurately. This ensures the reliability of results.

• 4. Compatibility: Glass wares are inert and resistant to most of the chemicals. It does not contaminate the sample and reagents. It does not interfere during reaction and storage.

• 5. Transparency: Glass wares are transparent. These reactions, color changes, etc can be observed.

• 6. Heat resistant: Glass wares tolerate high temperatures. Thus it is suitable for sterilization, evaporation, and boiling of samples or reagents.

• 7. Ease of cleaning: Glass wares are easy to clean. Thus it does not contaminate the sample or reagent during storage or diagnostic test.

• 8. Sample storage: Glass wares are non-reactive. Thus they are most suitable to store reagents.

• 9. Longevity: Glass wares have a long life span if they are handled carefully.

• 10. Environmental friendly.

Different Types of Glassware, and Uses:

Several glass wares are used in clinical laboratories. They are designed for specific purposes. The following are some examples of glass wares and their uses:

• 1. Beakers: Cylindrical containers with flat bottoms and a spout. Their capacities vary from 5 mL to 5000 mL. They are used to mix, heat, and hold liquids. They are not suitable for measuring liquid volume accurately.

• 2. Flasks: The capacity of the flask may vary from 25 mL to 5000 mL. The following are the types of flasks

• · Conical flasks (Erlenmeyer flask): They are cone-shaped with narrow necks. They are used to mix, to heat, and to store liquid. Its conical shape allows easy mixing of liquids without splashing.

• · Flat bottom round flasks: They are mainly used to heat liquid.

• · Round bottom flask: They are mainly used to be heated in a naked flame or in an electrothermal mantle.

• · Volumetric flask: They are pear-shaped, flat Bottom with narrow long necks. The neck has a marking that indicates the capacity of the volumetric flask. The neck is fitted with a stopper. They are used to make the volume of liquid accurately.

• 3. Test tube:

• 4. Watch Glass: They are circular concave-shaped pieces of glass. They are used to cover the beaker mouth. They are also used as a surface for evaporation or crystallization.

• 5. Petri dish: They are circular, shallow dishes with a lid. They are used to hold culture media, to grow microorganisms in culture media, and to observe microorganism colony.

• 6. Funnel: They help to separate solids from liquid or liquid from liquid or to pour liquid, chemicals, and solutions into the container

• 7. Condenser: They are glass tubes with a cooling coil. They are used to condense vapor into liquid.

• 8. Desiccators: They are sealed containers with drying agents. They are used to store chemicals sensitive to moisture.

• 9. Graduate cylinder (Measuring cylinder): They are toll narrow container. They have markings on their wall. They are used to measure the volume of liquid. They are not as accurate as pipettes.

• 10. Burettes: They have long graduated tubes with a stopcock. They are used to transfer liquids accurately during analysis or titration.

• 11. Pipettes: They are used to transfer accurate volume of liquid. Pipettes may be micropipettes and volumetric pipettes. Micropipettes are used to transfer liquid in a microliter. Volumetric

Pipettes are used to transfer liquid in milliliters. There are five types of pipettes

• · Graduated pipettes: They are available from 0.1 to 10 ml capacities.

• · Serological pipettes: They are marked up to the tip. They are used to transfer reagents, blood, serum, plasma, etc.

• · Mohr pipettes: They are graduated above the tip. They are used as serological pipettes.

• · Volumetric pipettes: They transfer liquid to its full capacity.

• · Pasteur pipettes: They are used to separate plasma and serum from cells.

Cleaning of glass wares:

Cleaning of glass wares is an essential step for reliable laboratory test reports. The following guidelines are followed to clean glass wares.

• 1. Prerinsing: Rinse the glassware immediately after use. Rinse the glass wares suitable liquids that can dissolve the contents of the container. For example water, acetone etc.

• 2. Soaking: Soaking is used to remove stubborn residues on glass container walls. Cleaning solutions such as mild detergent solutions, enzymatic cleaners, and acid-base solutions are used in the soaking step.

• 3. Brushing: A soft brush or scrub is used to remove contents from the outer and inner walls of the container soaked in soaking solution.

• 4. Rinsing: Rinse the glassware thoroughly with purified water. This removes the trace of cleaning agents present on the walls of containers. Repeat the rinsing multiple times.

• 5. Drying: Allow the glassware to dry in the air after rinsing. Sometimes oven at low temperature is used to dry glass wares.

Precautions: Avoid the use of hard scrub or brush, acid cleaning agent, and scratching on glassware walls.

Standardization of volumetric glassware:

Standardization of volumetric glassware is done to ensure the accuracy of glassware. Volumetric glassware, such as volumetric flasks, pipettes, and burettes, are used to measure volumes of liquids in the laboratory.

Volumetric glassware is standardized below

• 1. Volumetric flask: Volumetric flask is used to prepare solutions with accuracy. A volumetric flask is standardized by using a solution of known concentration. The solution is added to the calibration mark on the neck of the volumetric flask. The mass of solution and density of the solution are used to calculate the volume of the solution in the volumetric flask.

• 2. Pipette: A pipette is used to transfer accurate volume of liquid. The solution of known concentration is drawn into the pipette. The solution is transferred into a container. Its volume or mass is measured. The difference between the initial mass and final mass or volume gives the accuracy of the pipette.

• 3. Burette: Burette is used to deliver a known volume of liquid during titration. A solution of known concentration is added to the burette. The initial volume of liquid in the burette is noted. The solution is allowed to drain out from the burette into the container until the endpoint of the titration. The difference between the initial volume and final volume in the burette indicates the volume of liquid delivered by the burette.

Maintenance of volumetric glassware:

Maintenance of volumetric glass wares in the clinical laboratory ensures the accuracy and reliability of measurements of chemicals and reagents. The volumetric glass wares are maintained in the clinical laboratory as per below

• 1. Cleaning: Regular cleaning of glass wares prevents contamination and ensures accurate measurement. Mild detergent or specialized glassware cleaner with deionized water is used to clean glass wares. After cleaning rinse the glass wares using deionized water to remove any residue.

• 2. Drying: Allow glass wares to dry in air or in the oven at low temperature. Avoid cloth or paper or towel to dry the interior part of glass wares.

• 3. Calibration: Volumetric glass wares of calibration marks. It indicates the volume of contents in the volumetric glass wares. Check this mark regularly using reference standards. If required, recalibrate.

• 4. Record keeping: Maintain a proper record of the date of calibration. This helps to know the reliability of volumetric glass wares.

• 5. Regular inspection: Regularly inspect the volumetric glass wares for damage such as cracks, scratches, etc.

• 6. Storage: Store volumetric glass wares in a clean and dustfree area. Use protective caps to prevent entries of dust or contamination into volumetric glass wares.

• 7. Handling: Handle volumetric glass wares with great care and caution. Hold it by the appropriate part of volumetric glass wares such as the neck of the flask.

• 8. Temperature: volumetric glass wares expand or contract with temperature changes. Allow volumetric glass wares to room temperature before their use.

• 9. Chemical compatibility: volumetric glass wares do not react with most of the reagents in the clinical laboratory. However, compatibility between volumetric glass wares and reagents must be ensured. Use specialized volumetric glass wares for reactive reagents.

Pipettes - various types and different pipetting techniques:

Pipettes are used to measure and transfer small volumes of liquids. There are various types of pipettes.

• 1. Micropipettes: They are commonly used in molecular biology, microbiology, and analytical chemistry. They are available in several volume ranges such as P2 (0.2 to 2µL), P10 (1 TO 10 µL), P20 (2 to 20 µL), P100 (P1000 (100 to 1000 µL), etc. They are further divided into single channel and multiple channels.

  • · Single channel micropipettes: They are used to transfer single volume at one time.

  • · Multiple channel micropipettes: They have normally 8 or 12 channels to pipette. They are used if multiple samples are to be pipetted out simultaneously.

• 2. Pasteur pipette: It is also known as dropper. It is made of glass or plastic. It is not as accurate as a micropipette. It is commonly used to transfer liquid in qualitative analysis.

• 3. Serological pipette: It is used to deliver 1 mL to 50 mL liquid. It is commonly used in cell culture. It is not as accurate as micropipette.

• Volumetric pipette: It is used to deliver single specific volume with high accuracy. It is commonly used in analytical chemistry.

Pipetting technique:

It is a method to transfer liquid using pipettes.

• 1. Reverse Pipetting: Suck a slightly high volume of liquid into the pipette than the required volume. Touch the pipette tip with side inner wall of the container. Release the required volume of liquid into the receiving container. It is used for high accuracy.

• 2. forward Pipetting: It is a standard pipetting technique. Suck the required volume of liquid into the pipette. Transfer the liquid to the receiving container.

• 3. Multi dispensing: Multi-channel pipette is used to transfer multiple samples simultaneously.

• 4. Air displacement vs positive displacement: Pipettes work on principles of air displacement or by creating a vacuum. Micropipettes work on the air displacement principle. Plunger is used to create a vacuum to suck and transfer liquid. The positive displacement technique is used for viscous or volatile liquids. Here piston directly displaces the liquid.

• 5. Avoid contamination: A change of pipette tip is required between each transfer to avoid contamination.

• Calibration: Calibrate the pipette regularly to maintain accuracy..