half life of primers - (Aug/16/2006 )

hi,
i m working with PCR. a number of gene's genotyping were done by me . but now a days i m facing a great problem in CD14. i have already tried thrice with new primers. all the time it works up to four days and suddenly not working. all times repeting so. i thought that there might be some problem with my other chemicals. but the same chemicals are giving good results for other genes.is there any half life of primer??????????

I dont think there is half life for primers, but frequent freeze/thaw cycles can cause degradation of the primers. Also it depends on how the primers were resuspended.

if a primer doesnt seem to work, order new one, its cheap and quite fast to get a new one.

There's no half life for primer sets. Most primers keep under good condition for years.

However, when you first make up your primer set aliquot it out into lots of smaller volumes (10 to 100 reactions each depending on throughput) and then freeze them all and keep them frozen until you want to use them. Then they will only go through one round of freeze-thawing (which they don't like).