Best practices dictate that pipettes undergo preventive maintenance and calibration at least once per year. Calibration involves dispensing set volumes of a liquid, usually water, into the weighing pan of a calibrated balance. Service personnel correct for temperature, humidity, and atmospheric pressure, and then compare the expected weight to the actual weight. Among the numerous service options are end-user, in-house instrument service groups, third-party maintenance organizations, and the original manufacturer. All have their benefits and drawbacks. Small, independent service providers are numerous and focus on academic customers within a relatively small geographic area. Regardless of their size, service organizations work either through “depot” arrangements (pipettes are boxed and shipped to the servicer) or on-site. Servicers generally do not require a minimum number of devices for depot service, but all have requirements for on-site service. The reason pipettes require regular maintenance is that they are mechanical devices that are, in many instances, used constantly. Volatile acids, bases, and organic solvents wreak havoc on the seals, o-rings, and metallic components.
Seventy-eight percent of the respondents feel that their current pipette(s) are adequate for their research. The sources of errors our respondents encounter with their pipettes include: