Dropper, what is it, how to choose and buy it?

November 2, 2021

dropper , also known as a pipette, is a device used to transfer small amounts of liquids. They are used in the laboratory and also to dispense small amounts of liquid medications. A very common use was to dispense eye drops into the eye. The commonly recognized shape is a glass tube tapered to a narrow point, pipetted and fitted with a rubber bulb on top, although there are many styles of plastic and glass droppers.

The combination of the pipette and the rubber bulb has also been referred to as a nipple pipet. The name of the pipette is from the French scientist, Louis Pasteur, who used a variant of them extensively during his research. In the past, there was no equipment to transfer a chemical solution without exposing it to the external environment. Hygiene and purity of chemical compounds are necessary for the expected result of each experiment.

The dropper, both glass and plastic, can be sterilized and capped with a rubber bulb at the open end of the pipette to avoid contamination of the atmosphere. They are generally considered cheap enough to be disposable, however as long as the glass tip does not chip the dropper can be washed and reused indefinitely.

Although not as famous as the beakers , conical flasks, and Petri dishes commonly associated with laboratories and scientific research, there are few laboratory tools as important as the pipette. Also known as pipettes or chemical droppers, these small tubes transfer liquids from one container to another in exact, measurable amounts.

Although they may seem like mundane tools, pipettes are actually incredibly important to scientific research: Before they appeared in their current form some 50 years ago, scientists would do the same job with their own mouths.

Below we will talk more in detail about this indispensable laboratory equipment that has passed through the years and is still in use. Join us!

What is a dropper?

The dropper is a laboratory tool commonly used in chemistry, biology, and medicine for the transport of a measured volume of liquid, often as a media distributor. Droppers come in various designs for various purposes with varying levels of precision, from one-piece glass pipettes to more complex electronic or adjustable pipettes. Many types of drip work by creating a partial vacuum above the liquid holding chamber and selectively releasing this vacuum to draw and dispense liquid. Measurement accuracy varies greatly depending on style.

They come in two forms: volumetric dropper , used to transfer a single specific volume of liquid, and metering dropper, used to transfer variable and measured volumes. Droppers in their current form appeared in the 1970s, to replace the old and dangerous practice of mouth pipetting, where scientists transferred liquids in the laboratory using straws and suction from their own mouths, regardless of the potential dangers.

Dripper overview

In laboratory use , drippers should not be used for high precision work as drippers are not designed to measure a specific volume; however, it can be used to add reagent drops. Each type of dropper is designed to produce a specific drop volume, but this is not very accurate. Before using an eyedropper, the tip should be carefully examined for cracks. In order to increase precision, the pipette should be rinsed with the reagent.

To use the dropper, squeeze the bulb to push air out of the pipette and dip the tip of the pipette into the solution vertically. Gently relax the bulb to draw out the solution and make sure the solution is not overflowing into the contaminating bulb. To dispense the reagent, hold the tip against the side of the target container at a 30-45 degree angle.

History of the dropper

Although modern droppers have only been around since the late 1950s, pipettes as scientific tools have been around in some form since the late 1800s. First created by the French biologist Louis Pasteur, who invented the pasteurization process, the dropper could used to aspirate and dispense liquids without fear of contamination. Unfortunately, Pasteur’s tools did not catch on quickly because any scientist who wanted to use pipettes would have to create their own personal glass set.

Many continued to use the tried-and-true – and incredibly dangerous – drip method, where scientists transferred liquids using straws and their own mouths, even if that liquid was toxic or radioactive. It was not until the late 1950s that the former German soldier Henrich Schnitger, who hated the practice of mouth pipetting, would develop the modern mass-produced pipette. These, fortunately, would quickly find out.

Dropper types

Its specific purpose is to aspirate a liquid of the laboratory user’s choice, then contain the liquid so that it can be transferred to another container. Some droppers are not very accurate and are intended to transfer rather than measure liquid, while others are very accurate and measure the volume of liquid. Here the different types:

Volumetric dripper

The volumetric drippers are used to transfer a specific volume of a given liquid. It usually has a capacity of between 1 and 100 ml. They can be shaped like a rolling pin, with two thinner ends and a thicker bulge in the middle. These are used when precision in measuring the transferred liquid is important for recording.

Measuring dropper

The measuring dropper are straight tubes with a tapered end. They have clearly marked hash marks along the side of the tube. So multiple amounts of liquid can be measured with a single pipette. This type of dropper can generally measure a volume between 0.1 mL and 25 mL. While they can measure multiple amounts of liquid at once, imperfections in the internal diameter of their tube mean that they are not as accurate in their measurements as volumetric droppers.

Mohr and Serological Dropper

The measuring dropper is subdivided into Mohr and serological droppers . The difference between these two types is that Mohr dropper hash marks or gradations always end before the pipette tip. Whereas serological pipettes have gradations that continue to the tips. Additionally, some serological pipettes are blow pipettes as well.

These droppers have an open top, much like a straw, where the user places their thumb over the top to create a vacuum and seal the liquid in the pipette. Blow-off pipettes allow you to blow into this open end to get the last bits of liquid left in the pipette into your receiving container, for greater precision.

Dropper uses

Regardless of the type of dropper used, its use requires care and attention. To avoid damage when drawing a liquid, place the pipette 1/4 inch from the bottom of your container. Then place your finger on the end or gently squeeze the bulb at the end, depending on the type of pipette.

When the required volume has been raised, tap the side of the pipette to remove excess drops . Then hold the pipette at a 10 to 20 degree angle when dispensing. No, do not blow through a pipette to remove excess liquid.

Other uses of the dropper

The constriction towards the tip of the dropper can be covered with a little tissue paper or cotton. This to filter solids from small amounts of liquids. The bulb can be plugged in and squeezed to help viscous solutions filter through more quickly. With a little skill, the dropper can also be used for microscale column chromatography. With appropriately fine silica gel, the bulb can be squeezed for microscale flash column chromatography.

The medical laboratory required high efficiency and precision for drug testing and disease observation. Droppers are commonly used in the medical laboratory because of their essential precision. The design of the dropper enables high effective throughput in the medical laboratory. Produces a constant droplet volume. This reduces the concern of liquid remaining in the pipette.

Cleaning the dropper

The dropper requires cleaning after each use, to ensure they remain accurate and to avoid contamination of any previous content. To clean one, draw distilled water into the dropper and tilt it so that the water makes contact with the inside surface of the dropper. Repeat this process twice, then rinse the entire pipette with distilled water to finish cleaning.

Dripper Calibration

The calibration of the dropper is an important consideration in laboratories using these devices. It is the act of determining the accuracy of a measuring device compared to traceable reference standards. Calibration of is essential to ensure that the instrument operates according to expectations and according to defined work regimes or protocols.

It is also considered a complex issue because it includes many elements of the calibration procedure and several options for calibration protocols. As well as brands and models of pipettes to consider.

Dr. Loony Davis5
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Born and raised in Brussels in an English family, I have always lived in a multicultural environment. After several work experiences in marketing and communication, I came to Smart Water Magazine, which I describe as the most exciting challenge of my career.
I am a person with great restlessness and curiosity to learn, discover what I do not know, as well as reinvent myself daily, someone who is curious about life and wants to know. I enjoy sharing knowledge.
This is my personal project but I also collaborate in other blogs, it is the case, the most important web on water currently exists in the US, if you are interested you can read my articles here.

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