In medical laboratories, glass wares and plastic wares are widely used.

Glass ware:

Laboratory glass wares are the equipment used in scientific work. In medical laboratories, glass wares are usually manufactured from boro-silicate glass, due to following properties:-

  • They are resistant to the action of chemicals like, water, acid, halogens and organic solvents.
  • They are transparent and can withstand thermal stress.
  • They can withstand mechanical breakage.

Safe handling of glass wares:

  • Wear protective clothing such as gloves, eye protection, aprons, lab coat while working with laboratory glass wares.
  • Use care in handling and storing glass ware to avoid damaging it.
  • Do not use any chipped or cracked glass ware as you may get cut.
  • Thoroughly clean and decontaminate glass ware after each use.
  • When handling cool flasks, grasp the neck with one hand and support the bottom with the other hand.
  • Lift cool beakers by grasping the sides just below the rim. For large beakers, use two hands, one on the side and one supporting the bottom.
  • Never carry bottles by their necks.
  • Use a cart to transport large bottles of dense liquid.
  • Dispose of broken or defective glass ware safely. Use a purpose-designed disposal bin that is puncture resistant and clearly labeled.
  • Never heat damaged glassware as resistance to heat is equally compromised.
  • Heat up and cool down glassware as slowly as possible even when using Boro-silicate glass which has a very low coefficient of expansion. Maximum working temperature for Boro-silicate glass is 500°C however special precautions must be employed even when working above 150°C.
  • When diluting concentrated acids, thin walled glassware should be used since the heat evolved by the procedure often cracks thick glass wares.
  • Do not heat extra thick glassware. This glassware is ideal for working under vacuum when higher mechanical strength is required, but this glass is less heat resistant.
  • When heating glass bottles, loosen the caps.
  • Because of the danger of chemical and bacteriological contamination, pipettes or glass-rods should never be left lying on the bench.

Cleaning of glass ware:

The cleaning procedure for glassware depends on the type of material contained in it. Boro-silicate glass is resistant to most acids except hydrofluoric acid.

  • Soap, detergent or cleaning powder may be used to wash glass wares.
  • Avoid any detergents or cleaning solutions that contain abrasive particles.
  • Strong alkaline domestic or industrial detergents will dissolve the glass and eventually cause breakage.
  • Glassware should be cleaned as soon as possible to prevent the residues from hardening.
  • Ideally give glassware a rinse or soak with organic solvent to remove grease and then another thorough rinse with water.
  • Cleaning can be done in a glass washing machine or manually.

Volumetric ware:

Volumetric wares are apparatus used for the measurement of liquid volume.
They can be made from either glass or plastic wares. Volumetric wares are manufactured exclusively from boro-silicate glass.
Soda-lime glass is generally used for products where long-term exposure to chemicals is unlikely, e.g. one mark and graduated pipettes.
Volumetric glass wares has superior thermal and chemical resistance and is better suited to glassware for storage of solutions.
With everyday use, volumetric glassware requires recalibration. Soda-lime glass items will generally necessitate twice as many recalibrations as items constructed from borosilicate glass.
Example:- Pipettes, volumetric flasks, burettes, beakers, cylinders, etc.

Pipettes:

There are several types of pipettes, which have their own advantages and limitations. Pipettes are designated as class “A” or “B” according to their accuracy.

Class “A” pipettes are the most accurate and the tolerance limits are well defined that is, + 0.01, + 0.02 and 0.04 ml for 2, 25, and 50 ml pipettes respectively.

Class “B” pipettes are less accurate but quite satisfactory for most general laboratory purposes. Significant errors will result if the temperature of the liquid pipette is widely different from the temperature of calibration. The usual temperature of calibration is 20oC and this is marked on the pipette.

Sometimes, pipettes that dispense between 1 and 1000 Î¼l are distinguished as micropipettes, while macropipettes dispense greater volumes.

Commonly used pipettes are:-

  • Pasteur pipette
  • Air displacement pipette
  • Positive displacement pipette
  • Electronic pipette
  • Graduated pipette
  • Volumetric pipette
  • Transfer pipette

Specialized pipettes are:-

  • Glass micropipette
  • Ostwald-Folin pipette
  • Microfluidic pipette
  • Van Slyke pipette

Beakers:

Beakers are simple cylindrical shaped containers used to hold reagents or samples. Beakers are available in a wide range of sizes, from one millilitre up to several liters. Some are made of heat resistant glass or plastic and some are fitted with ground- glass stoppers Measurement of liquids can be made quickly with these vessels, but a high degree of accuracy is impossible because of the wide bore of the cylinders.

Burettes:

Burettes are long graduated tubes of uniform bore and are closed at the lower end by means of a glass stopper, which should be lightly greased for smooth rotation. A burette is volumetric measuring glassware which is used for the accurate dispensing of a liquid, especially of one of the reagents in a titration. They are made in capacities from 1 to 100 millilitres.

Flasks:

Flasks are narrow-necked glass containers, typically conical or spherical, used in a laboratory. Flasks come in a number of shapes and a wide range of sizes, but a common distinguishing aspect in their shapes is a wider vessel "body" and one (or sometimes more) narrower tubular sections at the top called necks which have an opening at the top.

There are four types of flasks having 25 to 6,000 millilitre (ml) capacities:-

  • Volumetric flasks
  • Conical (Erlenmeyer) flasks
  • Flat bottomed round flasks
  • Round bottomed flasks

Flasks can be used for making solutions or for holding, containing, collecting, or sometimes volumetrically measuring chemicals, samples, etc. for chemical reactions or other processes such as mixing, heating, cooling, and dissolving.

Test tubes:

Test tube is common piece of laboratory glassware which is open at the top and closed at the bottom. They are made of hardened glass or plastic materials that can withstand actions of chemicals, thermal shock and centrifugal stains. They are used in laboratories to hold, mix or heat various chemicals or samples.

Reagent bottles:

Reagent bottles are the containers with narrow openings generally used to store reagents or samples. They are made from glass or plastic in various shapes and size to store and transport liquid. The mouth of bottles is closed with bottle caps.

Petri dishes:

Petri dishes are swallowing transparent lidded dish which have number of uses in medical laboratories. They are made up of glass or plastic. They are used predominantly for the cultivation of organisms on solid media. They are made with diameters of 5 to 14 centimetre and a height to diameter ratio ranging from 1:10 to 1:4. To isolate, identify and study the characteristics of microorganisms it is essential to grow them on artificial media.

Funnels:

Funnel is a tube or pipe that is wide at the top and narrow at the bottom. Funnels are used in chemical laboratories to pour liquids into small mouthed containers and used with filter paper to filter sediment from a liquid.

There are various types of funnel used in laboratories. Some of them are:-

  • Plain funnels
  • Powder funnels
  • Filter funnels
  • Separatory funnels
  • Dropping funnels
  • Eco funnels
  • Buchner funnels
  • Hot filtration funnels