Sample preparation of cosmetic product requires extensive
extract clean up procedures prior to the instrumental analysis [16].
A 5 g cream sample, which was emulsion type water-insoluble
product, was dissolved in methanol–dichloromethane mixture
solution (1:1, v/v). Although not shown here, the major compounds,
such as paraffin oils and alcohols in extract, were partially
removed and still remained after extrelut cartridge as solid phase
replacements for traditional liquid–liquid extractions (supplementary
material, Fig. S2). Even though further multiple cleanup
steps could be needed to remove remaining interferences, these
steps should be minimized to ensure the adequate recovery of
n-nitrosamines. During the concentration step after elution from
extrelut cartridge, low recoveries (about 20–30%) were obtained
due to their volatility.