Comparison of hexane and petroleum ether to measure surface oil content

Many studies have measured surface oil on potato chips and spray dried powders using either petroleum ether or hexane. This study compared the effectiveness of the 2 solvents using aluminum squares to ensure oil stays on the surface of the sample during the measurement. Aluminum squares were sprayed with soybean oil, and surface oil was measured immediately and after 1 day. Each of the 8 aluminum samples were individually dipped for 1-2 s in either hexane or petroleum ether. For immediately extracted samples, there was no significant difference in the amount of oil extracted using either hexane or petroleum ether. For 1-day-old samples, hexane extracted more oil than petroleum ether. Neither method extracted all of the surface oil.