Effect of the lysis reagent on CEC. Compared with cholic acid, lysis with sodium hydroxide results in significantly higher CEC values (P = 0.0082) and lysis with TX100 in significantly lower CEC values (P = 0.0028). The SD between replicates is lowest for lysis with cholic acid. Dots and error bars represent mean and SD of triplicates. If no error bars are visible, they are contained within the symbol because of a very small variability of the measurements. CEC was calculated per well. CA, cholic acid; NaOH, sodium hydroxide; S1–5, sample 1–5; TX100, Triton X-100.