Getting the Pipette Cleaning Equation Right Every Time
Part 2: Pipette Cleaning Series
Image courtesy of Miele ProfessionalOur last post, You May Be Sabotaging the Important Pipette Cleaning Process, discussed that while clean pipettes are essential for producing accurate test results, many labs are likely not to have contaminant-free glassware. That’s because they use plastic siphon tanks which are not only ineffective at their job, but they also waste time, energy, and water.
The way to ensure cleanliness is to balance the cleaning equation. It combines the ideal water action, detergent, and heat for the right amount of time, ensuring cleanliness while conserving resources.
A Labwasher Gets the Equation Right
Although this balancing act sounds challenging, you can conquer it easily by using a laboratory glassware washer, which is programmed to ensure repeatable and analytically clean results.
To use a lab washer to clean pipettes, you need a direct injection basket. This basket enables you to place each pipette tip down in a protective plastic holder. The machine then injects water and detergent to provide a thorough cleaning. Afterwards, a DI rinse removes trace residues.
When looking for the right labwasher for your pipettes, keep the following in mind.
- Pipettes Like it Hot
Hotter temperatures generally clean and rinse better than cooler ones. A lab washer should be able to heat water and DI water up to 93°C.
- Motion Matters
When it comes to water, most people think that high pressure is good. In fact, while high pressure may help clean residues off glassware, there’s a catch. The more the pressure, the greater the chance of breaking delicate pipettes.
What you need is high circulation. By increasing the number of times the water and detergent are in contact with the pipette’s surface, you improve the cleaning action. So to produce analytically clean results, it’s best to look for lab washers with a circulation rate over 100 gallons of water per minute and a low discharge rate. These attributes will also reduce wash time, the amount of detergent required and increase energy efficiency.
Another enhancement for improving water efficiency in the cleaning process is, not surprisingly, to direct it exactly where it needs to go. Many washer manufacturers simply drill holes in the spray arm, sending all the water in one direction, not necessarily where it needs to be. The most efficient ones offer spray nozzles which angle and feather the jet spray, allowing for maximum water coverage and impact exactly where it’s needed.
- There’s No Time to Waste
The longer your wash, the cleaner your pipettes. The problem with long washes, however, is that you cannot afford to wait all day. Plus, you don’t want to be wasting water and if you heat it, energy. To achieve uncontaminated pipettes in the least amount of time, you need a washer with a high circulation rate. If you opt for a high wattage and high power labwasher that minimizes the number of gallons of water per cycle, you will reduce the time spent heating it up to temperature.
- Detergent Dos
Do use the detergent recommended by your lab washer manufacturer. They have done the legwork to determine the right type and amount of detergent to optimize the wash given the other three variables of the cleaning equation. When added to the mix, the right detergent and acid neutralizer will remove virtually any residue from glassware.
Miele’s lab washers are optimized to produce contaminant-free pipettes that give accurate test results while minimizing the use of time and water. Most runtimes are between 60 and 90 minutes, and utilize on average about 2.4 gallons of water per fill. ( undercounter) up to 9.1 gallons per fill for a large chamber washer. Miele’s pipette program takes 50 minutes to wash and then an additional 30 minutes of drying is recommended. Drying time is adjustable in case it’s determined more or less time is needed. Less water is used than is consumed in a siphon tank type washer. The A303 insert—holds up to 98 pipettes up to 18” long. The A202 insert holds up to 38 pipettes and is recommended for longer pipettes up to 21 inches long. This insert also has space for other glassware.