A mortar and pestle are fundamental laboratory tools: a bowl (mortar) and a grinding tool (pestle). They primarily crush, grind, and mix solids into fine powders or pastes. Despite ancient origins, they remain relevant in science for their direct mechanical action and benefits in sample preparation.
Fundamental Scientific Purpose
Mortar and pestle primarily reduce the particle size of solid materials. This process, known as pulverization or comminution, significantly increases the surface area of a substance. Increased surface area accelerates chemical reactions, improves solubility for extraction, and enhances dissolution rates.
Beyond size reduction, these tools effectively homogenize substances, creating uniform mixtures. Grinding and mixing ensure even distribution of constituents. This uniformity is essential for accurate, reproducible analytical results.
The mechanical force also disrupts biological structures like plant or animal tissues and microbial cells. This process, known as cell lysis, breaks down cell walls and membranes, releasing intracellular components like DNA, RNA, proteins, and metabolites. Cell lysis isolates specific biomolecules for analysis or purification.
Specific Scientific Disciplines and Applications
In chemistry, mortar and pestle sets prepare solid reagents for reactions, creating finer, more reactive powders. They also pulverize samples before dissolution, aiding solution preparation for analytical techniques like spectroscopy or chromatography. This ensures complete dissolution.
Biology and biochemistry frequently use these tools for processing biological samples. Researchers often grind plant leaves or animal tissues, sometimes with liquid nitrogen to preserve molecular integrity, to extract nucleic acids like DNA and RNA. This disruption releases genetic material for purification and analysis.
Pharmacology and pharmaceutical sciences use mortar and pestle sets for precise drug formulation. They triturate solid drug compounds into fine, uniform powders, essential for accurate dosages in capsules or tablets. They also create homogeneous mixtures for topical creams, ointments, and suspensions, ensuring even active ingredient distribution.
Geology and material science use mortar and pestle for preparing mineral samples. Geological samples are ground for techniques like X-ray diffraction (crystalline structures) or X-ray fluorescence (elemental composition). This ensures consistent sample properties for accurate analysis. Environmental scientists use them to prepare soil or sediment for contaminant analysis, ensuring uniform pollutant distribution and accessibility.
Factors Influencing Mortar and Pestle Selection
The choice of mortar and pestle material depends on the scientific application and the substance’s properties. Porcelain and ceramic mortars are hard, non-porous, and suitable for general grinding, though they can introduce minor abrasion. Agate, a hard, non-porous material, is favored for fine grinding and minimizing contamination, resisting abrasion and chemical reactions.
Glass mortars are chosen for chemical inertness and easy cleaning, ideal for reactive substances or when avoiding cross-contamination. However, glass is less durable and not suitable for grinding hard samples. Stainless steel mortars are durable and effective for harder samples, but risk introducing metal contaminants that can interfere with tests.
Selection considers sample hardness, desired powder fineness, and potential contamination. Chemical inertness prevents unwanted reactions. Ease of cleaning is also practical, especially in labs with diverse samples.