Glass Pipettes

A volumetric (transfer) pipette has a single etched mark and delivers one specific volume (e.g., exactly 10.00 mL) with the highest accuracy. A measuring (graduated) pipette has multiple graduation marks and can deliver variable volumes, but with slightly lower accuracy than a volumetric pipette at any given volume.

A Mohr pipette is graduated but the graduations stop before the tip, leaving an unmarked section. A serological (blow-out) pipette is graduated all the way to the tip, and the last drop is blown out to deliver the full volume. Serological types have a frosted band or etched ring at the top to indicate blow-out.

Soak used glass pipettes in a detergent solution or chromic acid cleaning solution immediately after use. Rinse thoroughly with tap water, then deionized water. Dry in a pipette dryer or oven. For critical analytical work, soak in dilute HCl or HNO₃, rinse with DI water, and oven-dry. Never let residues dry on the glass.

Use glass pipettes when working with organic solvents (chloroform, acetone, toluene) that dissolve polystyrene, when Class A volumetric accuracy is required by your method, or when you need to autoclave and reuse pipettes. Glass is also preferred for some titration and wet chemistry applications where disposable plastic would introduce unacceptable tolerances.

Yes. We stock both 5.75-inch and 9-inch borosilicate glass Pasteur pipettes in bulk packs. Pasteur pipettes are used with rubber bulbs for qualitative liquid transfer, spotting TLC plates, and general bench work. They are meant for single use or can be cleaned and reused for non-critical applications.