Providing accurate and safe pipetting

Liquid Handling Systems, commonly known as auto pipettes or micropipettes, are products for safe, accurate and ergonomic laboratory applications and are an important part of every lab in the field of research and diagnostics which require liquid handling. These are precision instruments used to provide accurate, reproducible and safe pipetting in the most demanding liquid handling laboratory applications.

Micropipettes are available with mechanical and electronic functions and have different volume ranges with +/- inaccuracy of 0.003 µl for 0.3 µl volume range to +/- inaccuracy of 0.04 µl for 3 µl volume range pipettes. Single and multichannel air displacement pipettes with adjustable volumes were developed towards the end of 1960 and were first manufactured in the beginning of 1970 by Professor Osmo A Suovaniemi (Suovaniemi, US patents 3,855,868; 4,058,370 and 4,215,092).

In 1970 the quality of both single and multichannel pipettes and the disposable pipette tips required was quite variable. Today, after three decades of development, mechanical pipettes exhibit excellent accuracy and precision. Yet, results with mechanical and even electronic pipettes are still user-dependent, and experience and skill clubbed with lots of training are still required to reach high-quality results.

Globally, there are numerous makes of pipettes (or liquid handling systems) available, with new makes coming to the market all the time. End user's acceptance trends show that pipettes with light plunger action and smooth function have increasing demands, at the same time sturdy pipettes with rugged look are being accepted with the belief they are durable. In certain fields of laboratory use, where sterilisation is of importance, autoclavable pipettes are being preferred.

A pipette, whether mechanical or electronic, must be well balanced and light in weight. In case of mechanical pipettes, the plunger should be light and smooth and tip ejection should be executed with minimum effort. To illustrate this point, evaluations have been performed to assess the pressure needed to operate mechanical pipettes. It was found that with some manufacturers' units, up to 4 kg of pressure (40N-45N force) was needed to depress the plunger at second stop of pipetting. If this is multiplied by what would be considered to be a day's work (i.e, 1,000 pipetting movements), the pressure exerted by the operative equals that of the weight of an average elephant. Prolonged use of pipettes of this nature drastically increases the risk for work-related upper limb disorders (WRULD).

In laboratories for diagnostic tests and research the nature of work means high level of concentration with respect to better accuracy and precision. Occupational health physicians involved with laboratory workers report a number of individual complaining of pain in the forearm and neck due to repeated strain injury (RSI), particularly during the period in which heavy pipetting action pipettes are used.

The pipetting force influences accuracy and precision. Keeping in view the importance of lighter pipetting action to reduce work related upper limb disorders, companies have now developed fully autoclavable mechanical pipettes, thereby, supporting the industry and laboratory workers globally with a choice of lighter pipetting action pipettes available.

(The article is contributed by Transasia Bio-Medicals. They can be contacted at transasia@transasia.co.in)