Chemical Compatibility of Laboratory Plastics vs Glassware (AU)

Chemical compatibility is not a minor detail. It determines whether your container stays intact, whether your sample remains uncontaminated, and whether your results drift because the container leached additives or absorbed analytes. In wet chemistry, plastics can be excellent for some reagents and disastrous for others. Glassware is generally more universal, but it has specific limits too.

This guide explains what reacts with what, why failures happen, and how to choose the right material for real lab workflows.

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The short answer labs can use

• Glass (borosilicate) is usually the safest default for organic solvents, heat, and long storage, but it must not be used with hydrofluoric acid and it can be attacked by strong alkalis over time.
• Plastics are great for aqueous acids and bases, impact resistance, and single-use contamination control, but many plastics fail with strong organic solvents, oxidisers, or heat.

If you only remember one rule, use this:
If you have strong organic solvents, heat, vacuum, or long storage, start with borosilicate glass. If you have corrosive aqueous chemistry and you need impact resistance, consider the right plastic, not just any plastic.

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Why compatibility failures happen

1) Swelling and stress cracking

Some solvents diffuse into plastics, causing swelling, softening, or sudden cracking. You may not see damage immediately, then the bottle fails on day three.

2) Leaching and contamination

Plastics can leach additives, stabilisers, slip agents, or plasticisers into solvents, especially organics. That matters for trace analysis, chromatography, and sensitive synthesis.

3) Adsorption and sample loss

Some analytes adsorb onto plastic surfaces, lowering recovery. This is common with hydrophobic compounds, some proteins, and trace organics.

4) Temperature and time

Compatibility is not only chemical. It is chemical plus temperature plus exposure time.
A plastic that is fine for a quick transfer can fail for overnight storage.

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Glassware: where it wins, and where it does not

Strengths of borosilicate glass

• Broad resistance to most acids, salts, and many solvents
• Low leachables, good for analytical purity
• Handles heating, reflux, and repeated wash cycles well
• Stable dimensions for repeat measurements

Limits of glass

• Hydrofluoric acid (HF) attacks glass, do not store or handle HF in glass
• Strong alkalis can attack glass surfaces over time, especially hot solutions
• Breakage risk, requires handling discipline

If you are heating organics, running reflux, distilling, or doing solvent storage, borosilicate is typically the correct baseline.

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Plastics: which polymer is used for what

Polypropylene (PP)

Best for:

• general aqueous solutions
• many acids and bases at room temperature
• centrifuge tubes, general containers

Risks:

• not ideal for many strong organic solvents, especially long exposure
• softens at elevated temperatures

Polyethylene (HDPE and LDPE)

Best for:

• many acids and bases
• large chemical storage where impact resistance matters
• common for bulk aqueous reagents

Risks:

• limited compatibility with many aromatic and chlorinated solvents
• can allow permeation of some solvents and gases over time

Polytetrafluoroethylene (PTFE)

Best for:

• aggressive chemicals, many strong solvents, acids, and bases
• best overall chemical resistance among common lab plastics
• liners, tubing, stopcocks, seals

Risks:

• cost
• not transparent, sometimes less convenient for visual checks

Polyvinyl chloride (PVC)

Best for:

• some acids and salts, often used more in tubing than lab containers

Risks:

• many organic solvents can cause swelling and leaching
• plasticiser concerns depending on formulation

Polycarbonate (PC)

Best for:

• impact resistance, some aqueous solutions

Risks:

• stress cracking with many organic solvents
• not recommended for solvent-heavy chemistry

Polystyrene (PS)

Best for:

• disposable labware for aqueous, low stress use

Risks:

• poor with many organic solvents
• not suitable for solvent storage or aggressive chemistry

Fluorinated polymers (FEP, PFA)

Best for:

• high purity and high chemical resistance, similar intent to PTFE
• excellent for many aggressive solvent and acid workflows where contamination control is critical

Risks:

• cost
• often used for specialised applications

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Practical compatibility guidance by chemical type

Strong mineral acids (aqueous)

Examples: hydrochloric, nitric, sulfuric, phosphoric

• Often compatible with HDPE and PP at room temperature
• Glass is usually fine for many acids, but check concentration and heat
• For strong oxidising acids, and for long storage, consider higher resistance materials and supplier guidance

Strong bases (aqueous)

Examples: sodium hydroxide, potassium hydroxide, ammonium hydroxide

• PP and HDPE often perform well at room temperature
• Glass can be attacked by strong alkali over time, especially hot
  If you store hot base, plastic can be safer for the container, but you still need compatibility confirmation for concentration and time.

Organic solvents

Examples: acetone, acetonitrile, ethanol, methanol, toluene, hexane, DCM

• Glass is usually the safest option
• Many plastics are at risk of swelling, stress cracking, or leaching
• PTFE, FEP, PFA are generally the safest plastics for organics

Chlorinated solvents and aromatics

Examples: dichloromethane, chloroform, toluene, xylene

• Many common plastics are poor choices for long contact
• Prefer glass or fluoropolymer components

Oxidisers

Examples: hydrogen peroxide, bleach solutions, strong oxidising mixtures

• Compatibility depends heavily on concentration and temperature
• Avoid assuming any plastic is safe without checking a compatibility chart and SDS guidance
• Use glass or fluoropolymer where appropriate and verified

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Choosing material by workflow

Sample storage for chromatography and trace analysis

Best default: glass, especially amber for light-sensitive samples
Reason: lower leachables and lower adsorption risk in many workflows.

Routine aqueous buffer prep and handling

Best default: PP or HDPE
Reason: impact resistance, good aqueous compatibility, lower breakage.

Heated solvent work, reflux, distillation, rotavap

Best default: borosilicate glass
Reason: thermal performance and solvent compatibility.

Highly aggressive chemicals, HF, or extreme compatibility needs

Best default: PTFE or fluorinated polymers
Reason: chemical resistance. HF should be handled with appropriate compatible materials and site SOPs, not glass.

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Buying criteria labs should use

1) Confirm exposure conditions

Ask: Is this a quick transfer, or a 7-day storage?
Ask: Is it room temperature, or heated?

2) Check compatibility at the polymer level

Do not accept “plastic bottle” as a specification. You want PP, HDPE, PTFE, FEP, PFA, or similar.

3) Consider contamination risk

If the method is trace-sensitive, assume plastics can contribute leachables unless proven otherwise.

4) Consider permeability

Some plastics allow slow solvent loss or water uptake over time. This matters for standards, volatile solvents, and long storage.

5) Use SDS storage guidance

If the SDS says protect from light, use amber. If it says avoid moisture, use a desiccator. If it says incompatible with glass, do not use glass.

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Quick FAQs

Is glass always more chemically resistant than plastic?

Not always. Glass fails with HF and can be attacked by strong alkalis over time. Some plastics like PTFE outperform glass for aggressive chemical resistance.

Why did my plastic bottle crack even though the solvent is common?

Solvent compatibility depends on polymer type, exposure time, and stress. Polycarbonate and polystyrene, for example, can stress crack with many solvents. Tight caps and physical stress can accelerate failure.

Are plastics safe for long-term solvent storage?

Often not, unless the polymer is appropriate and verified. For many organic solvents, glass is the safer standard. For specialised high resistance needs, fluoropolymers are used.

Does amber plastic solve light sensitivity?

Amber helps with light exposure, but it does not address chemical compatibility. You still need the correct polymer for the reagent.

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References for external linking (high authority)

These are strong reference targets you can link in a website version:

• ASTM D543: Resistance of plastics to chemical reagents
• ISO 175: Plastics, methods for determining the effects of liquid chemicals
• ASTM E438: Glasses used in laboratory apparatus
• ISO 3585: Borosilicate glass 3.3 properties
• ISO 4796: Laboratory glassware, reagent bottles
• Safety Data Sheets (SDS) for each chemical, storage and incompatibilities section
• Safe Work Australia: Managing risks of hazardous chemicals in the workplace

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Choosing the right container material reduces breakage, contamination, and repeat work, especially in solvent-heavy and analytical workflows. LabChoice Australia supplies borosilicate laboratory glassware, reagent bottles including amber options, and compatible accessories to support safe and consistent wet chemistry in Australian labs. If you want help matching a reagent to the right bottle material, cap type, or storage setup, contact the LabChoice Australia team for practical guidance.