While mechanical, single-channel, adjustable-volume pipettes are most commonly found in research laboratories, I use them with high school chemistry students to introduce them to the concepts of accuracy, precision, and density at the beginning of each school year. In this lab, students measure volume using beakers, graduated cylinders, and adjustable pipettes, and measure mass using top-loading balances and analytical balances, to determine which combination of measurements provide the most accurate and precise value for the density of distilled water. Using an adjustable Proline Plus Pipette with a range from 100 to 1000 μL, I conducted this lab later in the school year without students, in order to compare it to similar pipettes purchased from other vendors. Overall, I found them comparable in many ways to other pipettes I’ve used in my lab that are available from other manufacturers. Specifically, I found them as durable and easy to use as the Finnipipett II (Fisher Scientific) and BenchMate II (Oxford Labware) pipettes. All three brands measured a range of volume from 100 to 1,000 μL. The Proline pipettes were similar in price ($221) to the Finnpipeete II line ($246), while the BenchMate II line was more expensive ($350). All three come with thorough, easy-to-follow instructions. In terms of durability, it is important for teachers to remind high school students to keep the volume within the range printed on the pipette. If students turn the adjustable dial on the pipette past the accepted volume range, the dial will “stick” and the pipette will become unusable. Based on my comparison, I would recommend the Proline Plus Pipette by Biohit to teachers who are interested in using adjustable volume pipettes with their students. The list price of this brand is a little lower than other brands tested, making it a more economical choice for most teachers.

Amy Murphy