Pasteur Pipettes: what Claude and GPT would buy

Two AI models chose on their own, with no web access. Nobody tested these products: this is what each one says, and how to check it.

They disagree: Claude chooses Fisherbrand and GPT chooses Corning

In Industrial & Scientific, Claude and GPT choose the same brand in 52 of 107 categories.

Claude Opus 5.5 · October 29, 2026

Fisherbrand (brand)

Fisherbrand disposable borosilicate glass Pasteur pipettes are a widely used, solvent-safe standard in both standard lengths.

Not for: Anyone transferring biological liquids where glass breakage is a sharps risk; use plastic transfer pipettes instead.

GPT 6.1 Sol · November 10, 2026

Corning PYREX (line)

Borosilicate glass offers broad chemical compatibility for routine laboratory liquid transfers.

Not for: Precise volumetric measurement, automated robotic dispensing, or hydrofluoric acid.

Claude also lists Corning among the brands that matter.

Samco (brand)

Samco polyethylene transfer pipettes are a shatterproof, built-in-bulb alternative for aqueous and biological liquids.

Not for: Organic solvent work or hot liquids, which need glass.

DWK Kimble (line)

Kimble Pasteur pipettes are a long-standing borosilicate alternative in standard lengths.

Not for: Labs already standardised on another glass supplier with no complaints.

Length. 5.75 in for general use; 9 in for reaching into tall tubes and flasks These are the two standard lengths, and the long version avoids touching container walls.
Glass type. Borosilicate for solvents and heat; soda-lime only for basic aqueous use Borosilicate tolerates solvents, heat and flame-pulling better.
Bulbs. Rubber or latex-free bulbs sold separately must fit the pipette top Glass Pasteur pipettes ship without bulbs, and a loose bulb cannot hold liquid.
Cotton plug. Plugged when used with vacuum or sterile work The plug keeps liquid and aerosols out of the bulb or vacuum line.
Plastic vs glass. Polyethylene transfer pipettes for aqueous and biological work; glass for organics Plastic removes sharps risk but swells or leaches with many solvents.

Shops seen in search results on November 5, 2026. A shop missing here may sell it too. Nothing was checked by a person.

Reusing disposable glass Pasteur pipettes with biological material
Throwing used glass pipettes into normal trash instead of a sharps or broken-glass box
Latex bulbs for users with latex allergy