Effect of 2% Triton X-100 on PicoGreen® fluorescence with salmon sperm DNA. PicoGreen® fluorescence with salmon sperm DNA is shown in the presence (○) or absence (■) of 2% Triton X-100. Background fluorescence, defined as fluorescence detected in the absence of added DNA, was subtracted from each data point. Fluorescence is measured as arbitrary units (A.U.). Data shown are the mean of 3 independent determinations. Lines were calculated by linear regression; r2 was >0.99. Analysis of the slope in the absence of Triton X-100 indicates that fluorescence increases by 3.5 ± 0.07 A.U. for every 10 ng/ml increase in DNA concentration.