Cross contamination associated with the use of multiwell culture plates for cytotoxicity assessment of volatile chemicals.

In vitro toxicity testing can involve technical problems due to the evaporation of volatile test chemicals. The cytotoxicity of two volatile chemicals (butanol and ethanol) has been assessed with neutral red assay in conventional microtiter plates. The non volatile DMSO chemical is used as a negative control. Under these conditions, an important cross contamination between test concentration groups has been observed. This affects cytotoxicity estimation which is overestimated. This cross contamination is prevented when special plates containing removable bars are used.