It is a very minute but essential part of laboratory apparatus that we use to measure the liquids accurately in science labs at school and colleges. It is usually secured with a burette clamp (which fixes it well that way we can start working on the chemical stuff) A stopcock has a hole in the middle, which liquids to pass through it. We open the stopcock (turning it up), and liquid can come out through bottom. The opposite is true when we close it, where the liquid shuts off instantly. This is very handy, as will allow us to measure the perfect amount of liquid for our experiments without any spillage.
Types of burette stopcocks available are many but have their own pros and cons dosent they. Take the example of glass stopcocks being extremely robust and can have a long lifespan too if they are maintained properly. One downside is that they can be a lot more brittle than plastic stopcocks so dropping or chucking one on the workbench may result in it breaking. In contrast, plastic stopcocks are usually more economical and lighter in weight. However, they are not as robust in comparison to glass stopcocks and therefore will be less durable.
On top of that, there are stopcocks which have a thin layer of DuPont Teflon on them too. They are able to withstand a more extensive list of chemicals that either the plastic or glass stopcocks, which allows them to be used with experiments utilizing stronger and/or corrosive substances. But, then they might be slightly difficult to manage when in use. At the end of the day, what stopcock provides the optimal solution for your lab will depend on individual experiments and how much money you have to spend on other equipment.
Maintain and Cleaning The Stopcock of Your BuretteCleaning it is very important to keep your burette stop cock running in top condition. Once you have finished using the stopcock, make sure to always wash out all liquid contents inside it with water. This will help avoid a build-up of residue within. If hard or harsh chemicals have been used, it is recommended that the stopcock be placed on a certain cleaning solution for several hours and rinsed again. This will make sure that all the chemicals are gone. NOTE: Overtightening the stopcock could damage it or make turning difficult in future.
There are two primary things to consider when you doing research on the best burette stopcock for your needs, that is - what experiments will it need to be used in & how much are you willing/planning to spend. For work involving stronger chemicals, Teflon-coated stopcocks may be best as it is resistant to the harsher substances. Though if you are on a tight budget maybe the plastic stopcocks would be your best option. You also have to take into account the type of experiments you are running as it will affect how big a burette do you need and what degree of accuracy is necessary, which determines your choice in stopcock.
Sometimes we have trouble with burette stopcocks while using them. Leakage is a frequent issue, and this might be because the stopcock needs to be screwed in tightly or perhaps that the rubber sleeve has become fittend-out thereby must get replaced. If the stopcock is sticky and will not turn easily, this can be because it has been over tightened or that there is some debris in it causing the valve to bind. Problem: A stopcock broke, which is one of the most common problems that occurs due to mishandling or chemical hazard. First and foremost it is imperative that you identify what the problem actually is because sometimes some of these issues indicate that you need to replace the stopcock in full.