Determination of Residual Amount of N-Methylpyrrolidone in Lubricating Oil by Headspace-GC

Headspace-GC was applied to the determination of residual amount of N-methylpyrrolidone (NMP) in lubricating oil. The sample 1.0 mL was heated in the headspace vial at 100 ℃ for 15 min. Then the headspace gas was separated on DB-1701 capillary column and detected with FID. Linear relationship was found between the peak area and the mass concentration of NMP in the range of 4.00×101-1.02×104mg·kg-1, with detection limit (3S/N) of 10 mg·kg-1. Recovery rates obtained by standard addition method were in the range of 98.5%-100% and RSD (n=6) was 1.8%.