Working with a pipette is of course very precise. The smallest drop can have the biggest consequences. Whether you are working with volatile, aqueous or viscous substances, this can all influence the release of the instrument. That's why you want your pipette to be well maintained and calibrated at all times so that it delivers the correct volume.
Romy van Roosmalen is Liquid Handling manager at VWR/Avantor Services. There they specialize in maintaining and calibrating volume measuring instruments such as pipettes. They carry out no fewer than 100,000 calibrations per year, both on location and at the Boxmeer branch. Avantor Services has been maintaining and calibrating a lot for years and they know everything about how you can continue to use your pipettes as best as possible. Read Romy van Roosmalen's three golden tips below.
Romy's golden tips:
1. Maintain your pipette
3. Calibrate your pipette
3. Make sure you pipette correctly
Tip 1: have your pipette maintained
To continue to use a pipette properly, you must maintain it. “You disassemble the pipette and take all the parts apart. Depending on the brand of pipette, there is some kind of grease on the parts, which we remove. We clean all parts thoroughly with ethanol, apply new grease to the individual parts if necessary and reassemble everything,” says Romy. How often you need to maintain it depends on the use and the substances you pipette with. “For example, if you only work with aquadest, double distilled water, then a pipette will not suffer much. If you work with acids, you will of course have to maintain them more often.”
Laboratory technicians used to do this themselves in the past, maintaining and calibrating pipettes. “But it is time-consuming work because you finish each pipette manually,” says Romy. “Then you lose a lot of time that you don't spend on research, which is where laboratories make money. In addition, today we are much more on top of the regulations. Laboratory technicians must be more accountable and demonstrate that everything is correct. Nowadays it is almost always done by external parties, such as us, for example.”
Tip 2: wait a minute… Calibrated!
Calibration, the word has been used a few times already. But what exactly does it mean? When calibrating, set the pipette to maximum volume and note the environmental factors, such as temperature, air pressure and humidity. You then take measurements. “You measure several times and check whether the pipette delivers what you expect,” Romy explains.
There is a lot to consider when calibrating, and it is very precise. Romy: “There are quite a few influences on a measurement, we exclude as many as possible. That starts with the room where you calibrate. It must be between 18 and 24 degrees and have a certain humidity. Once the environmental conditions are correct and your pipette has acclimatized, you can begin.
“You test for average accuracy and the spread of mutual measurements. If the spread is good but the average accuracy is not, we will adjust. You adjust the piston without adjusting the counter, or vice versa. You take measurements again. Is it still not correct? Then we replace parts of the pipette.” Is everything all right? A certificate is then printed out and the pipette is given a sticker with the calibration date and possibly a recalibration date.
Tip 3: pipette correctly
Calibration and maintenance: you can do it yourself. But it is a time-consuming job that requires a lot of accuracy. What can you easily do yourself to ensure that your pipettes work accurately? Romy: “Proper pipetting has a major influence on the volume delivered. In the past there was little attention for it, but of course you have to learn it well. That still doesn't always go well. If you don't know how to do something, ask questions.”
“And be aware of how your equipment works and how you handle it. For example, if you work in a fume hood, you automatically hold your pipette in a corner, which already has an effect on the release. Also think about the substances you use. Acid does more with a metal pipette plunger than with a glass plunger. As long as you are aware of environmental factors, the substances you use and your method of pipetting, you can go a long way. If you also have your pipettes maintained and calibrated a few times a year, you will continue to work accurately.”
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