Top Ten Tips for Making Stock Solutions

Having to make stock solutions is a part of everyday lab life…a tedious, but necessary, one. So why not make the process as streamlined as possible? Here are a few little tricks I picked up while I was still in the lab:

Check to see if anybody has a tried and tested recipe – why reinvent the wheel? If it ain’t broke, don’t fix it!
When making a new stock solution, use an online calculator to work out the amounts of reagent you need to add. They’re free, easy to use and save you time, hassle and can help stop you making mistakes. They’re also handy if you’re not particularly confident with your maths! There are loads all over the internet: have a Google and find one that’s right for you.
If you need to pH your solution, see if you can find a recipe that tells you how much acid or base to add. It gives you an indication of what you need to add to get your pH where it should be, and could save you loads of tedious dripping of acids or bases in front of a pH meter – especially if you may end up needing to add large quantities!
Have a rota – don’t always be the one stuck making the solutions for everybody else. If you’re all using them, you should all pitch in.
Think about quantities – how much are you going to need? Will it keep without going off? Or does it need to be quite fresh? If you can make things in bulk and leave it lying around, then go for big batches. If it’s something that has to be kept cool and in the dark, less may be more.
Have a clear, consistent labelling system in the lab. The last thing you want is for two people to be using different labels for the same things and getting everybody confused.
Is there an easier way to make the solution? For example, you can buy PBS tablets which you just dissolve in water, rather than adding all the separate components yourself. They’re not always expensive and can save you time – and sometimes time can be as valuable as money!
Keep your solutions clean – this is especially important in areas such as cell culture. Use aseptic technique and autoclave where appropriate.
Fool-proof labelling! Always say what strength your buffer is (1x? 50x?) and if you have room on the bottle, maybe consider giving some instructions to users as to how they should make it up so they don’t pester you afterwards!
Mix your solutions as you go. As you measure out your ingredients add them to water that’s already stirring on a magnetic plate. They’ll dissolve more easily. Otherwise you’ll end up with a bottle of water with a great big sludge at the bottom and your poor little magnetic flea will be completely bogged down.