What is the difference between 5X master mix and a 1X mix? I know its 5 times more concentrated. Eg. if the user needs 12mM MgCl2 and if the 5x master mix provides 25mM I need to dilute? what is the point of supplying at 5X concentration when I cannot use it readily?
There are many reasons to supply 5x master mix (higher concentration). One is of chemistry. For most chemicals especial organic chemicals, a high concentration is much more stable than a diluted solution; A mix with higher concentration is easier to handle, distribute and store, some buffers used in large volume are sold with 20x concentration (you only need 1 liter shipment of 20x stock to make 20 liters of buffer rather than a shipment of 20 liters of 1x buffer!); The most important reason is a high concentration master mix is much more convenient to use, for example if you have a 5x master mix and want to make a reaction of 20ul, you can take 4ul of your master mix, add 1ul (or 2, 3, 4 ) of your enzyme, add 4ul (or 5, 6ul) of your substrate (or template eic), and then add 11ul (or the required volume) of water to make up to 20ul. If your master mix were "1x" and you need 1x for your reaction, the "1x" master mix would be useless.
5x vs 1x helps keep purchasing, shipping & storage costs & resources lower, AND allows you to much more easily set up reactions with very dilute samples in large volumes without having to concentrate them first.
Dear Xin,
I agree with the comments given by Selene. Reagents in solution forms are more bulky compared to their solid and semisolid forms. One reason for preparing concentrated solutions is to save space and cost for their transportation and distribution. Concentrated solutions do not support growth of microbes. Thus, they are microbiologically more stable than dilute solutions.
As mentioned by Selene above, we often perform reactions in small volumes, particularly in molecular biology laboratories, such as PCR reactions. It is usually easy to dilute reagents instead of concentrated them.
There are many reasons to supply 5x master mix (higher concentration). One is of chemistry. For most chemicals especial organic chemicals, a high concentration is much more stable than a diluted solution; A mix with higher concentration is easier to handle, distribute and store, some buffers used in large volume are sold with 20x concentration (you only need 1 liter shipment of 20x stock to make 20 liters of buffer rather than a shipment of 20 liters of 1x buffer!); The most important reason is a high concentration master mix is much more convenient to use, for example if you have a 5x master mix and want to make a reaction of 20ul, you can take 4ul of your master mix, add 1ul (or 2, 3, 4 ) of your enzyme, add 4ul (or 5, 6ul) of your substrate (or template eic), and then add 11ul (or the required volume) of water to make up to 20ul. If your master mix were "1x" and you need 1x for your reaction, the "1x" master mix would be useless.
Make sure you understand that your master mix is not your reaction. In almost every case you need to add some other stuff into the master mix to make your reaction work. If your master mix is 1x and your reaction requires 1x, any thing added will increase your master mix volume and made it less than 1x, and your reaction will not work.
yes, if you start with a 1x mix, anything added to it (sample, primers) will dilute it below 1x. If you start with a 5x, you only need 1/5 rxn volume of that 5x & have the other 4/5 volume to add sample, primers or anything else needed. Do the math. It's not that hard.
- Badges
- Science method