Lithium borate (Li2B4O7) is the lithium salt of boric acid.
Uses
Lithium borate can be used in the laboratory as buffer for gel electrophoresis of DNA and RNA. It has a lower conductivity, produces crisper resolution, and can be run at higher speeds than can gels made from TBE or TAE (5-50V/cm as compared to 5-10V/cm). At a given voltage, the heat generation and thus the gel temperature is much lower than with TBE/TAE buffers, therefore the voltage can be increased to speed up electrophoresis so that a gel run takes only a fraction of the usual time. Downstream applications, such as isolation of DNA from a gel slice or Southern blot analysis, work as expected with lithium boric acid gels. Lithium borate is also an ingredient for use in making glasses and ceramics.
The recipe for 1 liter of 20X lithium borate (LB) DNA electrophoresis buffer is as follows: To 950 mL of dH2O, add 8.392 g of lithium hydroxide monohydrate and 36 g of boric acid, pH should be near 8.2. Adjust volume to 1 L and filter sterilize. This yields a final working concentration of ~10 mM lithium borate and a pH of 8.5. No EDTA is used because this would increase conductivity and is unnecessary in most applications.(adapted from[1])
Sodium borate is similar to lithium borate and has nearly all of its advantages at a somewhat lower cost, but the lithium buffer permits use of even higher voltages due to the lower conductivity of lithium ions as compared to sodium ions.
References
- ^ Brody, J.R., Kern, S.E.,Sodium boric acid: a tris-free, cooler conductive medium for DNA electrophoresis, BioTechniques, 36(2), pp.214-215, 2004.
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