I've begun quantifying all libraries with qPCR (Kapa kit) but I'm getting massive inconsistencies with the number of reads I get from samples in a multiplex pool.
I dilute each final library 1:1000000 (three 1:100 serial dilution) mixing at least 10 times by pipette after each dilution. This then puts me somewhere in the middle of the Kapa standard curve. Everything is run in triplicate and the R2 of the standard curve is always great >0.99.
I then normalise, pool and requantify by both Qubit & qPCR and generally get a pooled concentration of 9-11nM (what I might expect). Cluster density for the overall run is fairly good, but after indexing there's massive variation sample-to-sample (5-fold differences for my last set of TruSeq RNA libraries).
I've also Qubit'd and Bioanalysed each library (I use the average size between 200-700bp to normalise my Kapa qPCR). There are no dimers or evidence of over-amplification. The Qubit concetrations are slightly better than qPCR but still not great (R2 between qubit and cluster# is 0.52, but for qPCR it was 0.41)
Does anyone have a fool-proof method for qPCR? I was wondering if it's worth running mulitple dilutions of the same sample on the PCR plate, but I would quickly run out of space on my 96 well plate (I often have to do 24 libraries at a time).
Has anyone tried a homebrew probe assay?
I dilute each final library 1:1000000 (three 1:100 serial dilution) mixing at least 10 times by pipette after each dilution. This then puts me somewhere in the middle of the Kapa standard curve. Everything is run in triplicate and the R2 of the standard curve is always great >0.99.
I then normalise, pool and requantify by both Qubit & qPCR and generally get a pooled concentration of 9-11nM (what I might expect). Cluster density for the overall run is fairly good, but after indexing there's massive variation sample-to-sample (5-fold differences for my last set of TruSeq RNA libraries).
I've also Qubit'd and Bioanalysed each library (I use the average size between 200-700bp to normalise my Kapa qPCR). There are no dimers or evidence of over-amplification. The Qubit concetrations are slightly better than qPCR but still not great (R2 between qubit and cluster# is 0.52, but for qPCR it was 0.41)
Does anyone have a fool-proof method for qPCR? I was wondering if it's worth running mulitple dilutions of the same sample on the PCR plate, but I would quickly run out of space on my 96 well plate (I often have to do 24 libraries at a time).
Has anyone tried a homebrew probe assay?
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