New advice from BOLA and Labtex on cleaning and handling of PTFE products after use

Published: 25-Jul-2024

The companies share: "Abrasive scouring agents may result in a milkiness of the vessels made of PFA and FEP. You may use all neutral detergents (pH 7). For higher contamination levels, we recommend using an alkaline detergent up to pH 12"

"Only clean or dry vessels in a laboratory washing machine when they are completely open."

CLEANING AND RE-UTILISATION OF TUBING

Fluoroplastic tubing should only be reused provided the material to be cleaned is known and rated with + in the chemical resistance chart. With unknown substances, the reuse of tubing cannot be recommended.

Appropriate detergents are all water-soluble substances (such as salts, acids, lyes, etc.).

After use with toxic, hazardous materials or substances that can only be removed using organic solvents, the tubing should be professionally disposed of.

AUTOCLAVING AT +121 °C AND 134 °C

Vessels made of PTFE, PFA or FEP can be sterilised using steam at +121 °C / 30 minutes respectively at 134 °C / 10 minutes. Dry sterilisation at +160 °C is also possible.

Autoclaving/sterilisation of closed vessels can destroy them. Sterilisation of vessels made of fluoropolymers with high-energy radiation, gamma radiation or electron radiation is not recommended.

CLEANING FOR TRACE ANALYSIS

To prevent contamination with cations or anions in trace analysis, the vessels should first be filled with an 1N HCL and HN03 solution. This solution should be left inside for max. 6 hours at room temp then rinsed with clean distilled water.

Vessel surfaces can be cleansed by storing them for 24 hours in deionised water at +85 °C. Here, the vessels should be rinsed with deionised water.

PRESSURE RESISTANCE OF BOTTLES

Due to their thin walls, standard PTFE, PFA or FEP bottles should not be pressurised (from inside).

PLASTICS IN MICROWAVE OVENS

Fluoroplastics are suitable for microwave energy. Fluoroplastic vessels are particularly suitable for heating of aggressive chemicals. The resulting vapours must be sufficiently drawn off. Controlled drainage to a collecting vessel has to be arranged in case of a rupture to membrane in the digestion vessel. Other vessels may only be heated when open.

FLUOROPLASTICS – HEATING

It is difficult to heat PTFE due to bad heat transmission. The max. surface temp must not be exceeded.

Heating mantle with surface sensor:

When heating with a heating mantle, a large surface of the vessel is covered. This supports heat transmission and reduces heating period. Mantle must have a surface sensor to switch it off upon exceeding +260 °C.

Heating by a thermostat:

The heat transmission is provided by the bath medium (oils or other liquids). Controlled by an adjusted thermostat, the temparatures on the surface of the PTFE vessel won't become too high.

Methods to avoid are:

• Direct flame (e.g. gas burner), as the surface temp cannot be controlled
• Hotplate, where overheating could also occur."

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