Why You Should Not Pipette Any Liquid in the Laboratory
When conducting experiments in a laboratory, it is crucial to follow strict guidelines to ensure both personal safety and the accuracy of the results. One common question that often arises is whether it is acceptable to pipette any liquid. The answer to this question is a resounding no. This article will explore the specific reasons why you should only pipette certain liquids and not everything available in the laboratory.
Understanding Viscosity
When considering the suitability of liquids for pipetting, the viscosity of the liquid plays a crucial role. Viscosity refers to the liquid's resistance to flow. Liquids with low viscosity, such as water or alcohol, are easily and safely pipetted. These liquids have a smooth flow that makes them ideal for pipetting. On the contrary, highly viscous liquids, such as gel or thick syrup, are difficult to pipette and may lead to splashes or inaccuracies in measurements.
Identifying Suitable Liquids for Pipetting
It is important to carefully select the liquids you intend to pipette. Some common liquids that are safe and suitable for pipetting include:
Water - The most commonly used liquid for dilutions and rinsing. Aqueous solutions - Diluted solutions of various solutes in water, such as buffer solutions used in molecular biology. Alcohols (e.g., ethanol, isopropanol) - Often used as solvents or in sterilization processes. Plasma-free media - Commonly used in cell culture studies.For these and other similar liquids, the use of a pipette is highly recommended to ensure precise and controlled volumes.
Perils of Pipetting Dangerous Liquids
Some liquids, however, do present significant risks and should never be pipetted with a syringe or mouth. These include:
Corrosive liquids - These liquids can cause intense damage to tissues and equipment. Examples include concentrated acids or alkalis. Corrosive liquids can also eat through glass, which is a serious safety concern. Toxic liquids - Some chemicals are highly toxic in even minute quantities. This includes organic solvents such as toluene, xylene, or benzene, as well as poisoning agents like mercury or lead compounds. Liquids that dissolve glass - Certain highly reactive chemicals, such as hydrofluoric acid, are so potent that they can dissolve glass. Handling these substances with bare hands or through glass can lead to severe chemical burns. Metals and alloys in liquid form - While rare, there are instances where metals and alloys can be present in liquid form at high temperatures. The handling of such substances requires specialised equipment and should not be attempted by anyone without appropriate training.To avoid these risks, supervisors and safety guidelines must be strictly followed.
Why Not Pipette Corrosive Liquids with Your Mouth?
The use of one’s mouth to move dangerous liquids is unequivocally dangerous. Liquids, especially corrosive ones, can contain hidden impurities that may not be visible, leading to serious respiratory issues and contamination of other samples. Additionally, any splash or spill can expose the mouth and lungs to harmful chemicals, which can lead to long-term health complications. In addition, even water should not be dispensed directly into a container with your mouth, as cross-contamination can occur, leading to experimental errors or, in the worst case, culture contamination.
Conclusion
Safe and proper pipetting practices are essential in any laboratory setting. By understanding the characteristics of the liquids being pipetted and following safety precautions, researchers can minimize risks and ensure the integrity of their experiments. Always consult the material safety data sheets (MSDS) or other relevant documentation for specific liquid properties and handling instructions.