When selecting laboratory products, dimensions, capacity and design are not the only important factors. Resistance to the chemicals that will contact the product is equally critical. Bottles, tubing, seals, stopcocks, plastic containers and glassware do not react to chemicals in the same way. An unsuitable material may swell, crack, soften, discolor, leak or contaminate the sample. For this reason, chemical compatibility should always be considered when selecting laboratory equipment.
What Is Chemical Compatibility?
Chemical compatibility describes a material’s ability to maintain acceptable physical and chemical properties when exposed to a particular chemical.
A material described as “chemically resistant” is not necessarily resistant to every chemical under every condition. Compatibility can change significantly with concentration, temperature and exposure time.
Key Factors to Consider
Chemical type: Acids, bases, organic solvents, oxidizing agents and other reactive substances can affect materials differently.
Concentration: A material suitable for a dilute solution may not be suitable for the same chemical at a higher concentration.
Temperature: Chemical attack can accelerate as temperature increases. A material that performs well at room temperature may become unsuitable at elevated temperatures.
Exposure time: Brief contact and long-term storage are very different conditions. Storage containers require particular attention to long-term compatibility.
Mechanical stress and pressure: Chemical exposure combined with pressure, mechanical stress or repeated movement may affect material performance.
Common Laboratory Materials
| Material | General characteristics |
|---|---|
| Borosilicate Glass 3.3 | High resistance to many chemicals and good thermal properties |
| PP – Polypropylene | Good resistance to many acids, bases and aqueous solutions |
| PE / HDPE | Suitable for many chemicals and widely used for bottles and containers |
| PTFE | Extremely broad chemical resistance; widely used for critical contact components |
| PS – Polystyrene | Suitable for selected aqueous applications but limited with many organic solvents |
| PVC | Compatibility depends strongly on formulation and operating conditions |
These are general guidelines only. Final selection should always be based on manufacturer compatibility data and actual operating conditions.
How Should a Chemical Compatibility Chart Be Used?
Identify the chemical first, then consider its concentration, operating temperature and expected contact time. Check the material rating in the manufacturer's compatibility data.
Compatibility charts are generally based on defined test conditions. When actual laboratory conditions differ—particularly in critical applications—a preliminary compatibility test may be appropriate.
Is Checking the Body Material Enough?
No. This is a common selection mistake.
For example, the glass body of a separatory funnel may be compatible with a solvent while its stopcock, seal or stopper may not be.
The complete fluid-contact path should therefore be evaluated:
Body + cap + seal + stopcock + tubing + fittings
Every component that contacts the chemical matters.
Signs of Chemical Incompatibility
Warning signs may include swelling, softening, hardening, cracking, cloudiness, discoloration, deformation, increased permeability and surface deterioration.
Importantly, incompatibility may also cause extraction, adsorption or sample contamination without obvious visible damage. This can be particularly important in analytical laboratory applications.
Conclusion
When choosing laboratory equipment, asking “What material is this product made from?” is only the first step. The more important question is:
“Is this material compatible with my chemical and my actual operating conditions?”
Chemical type, concentration, temperature, exposure time and all wetted components should be considered together. Correct material selection contributes to safer operation, longer equipment life and more reliable laboratory results.
