Blow-out (viscous) and Self-draining (non-viscous) describe which two pipette drainage characteristics, with BO and SD correspondences?

• A. BO: Serologic, Ostwald-Folin; SD: Mohr, Volumetric
• B. BO: Mohr, Volumetric; SD: Serologic, Ostwald-Folin
• C. BO: Mohr, Serologic; SD: Ostwald-Folin, Volumetric
• D. BO: Ostwald-Folin, Mohr; SD: Serologic, Volumetric

Answer: (A)

Drainage characteristics describe whether the delivered volume includes a final expelled drop or is obtained by gravity draining to the mark. Blow-out pipettes are designed to deliver the entire nominal volume by actively expelling the last drop, which is especially important for viscous liquids that cling to the walls. Serologic pipettes are built to be blown out to the tip, and Ostwald-Folin pipettes are also used as blow-out types for viscous samples, ensuring complete delivery.

Self-draining pipettes rely on gravity to drain the contents to the calibration mark, so no blowing is required. Mohr pipettes and Volumetric pipettes are designed for self-draining delivery, with volumes read at the mark and complete drainage achieved without blowing. Therefore, the two drainage characteristics map as blow-out to Serologic and Ostwald-Folin, and self-draining to Mohr and Volumetric.