Development of a database to characterize the density of nail polish samples by magnetic levitation
This study describes a simple and non-destructive method to characterize the density of nail polish samples using magnetic levitation (MagLev). Dried nail polish samples were levitated in a 3M MnCl2 paramagnetic solution between two permanent NdFeB magnets. The levitation heights were measured using ImageJ software and the density was calculated by comparing the sample data to a standard density bead linear regression curve. A database of the density values of 76 different nail polish samples from seven different manufacturers was compiled. Questioned nail polish samples may be compared to samples in this database in order to identify a potential manufacturer. The results suggest that density values may be more discriminating that FTIR analysis in distinguishing similarly colored nail polish. Demonstrable differences were also observed in the density of nail polish samples collected from a microscope slide verses in situ sampling of the same nail polish from a fingernail.