Determination of 4 Metal Antiknock Agents in Gasoline by Gas Chromatography-Mass Spectrometry

A method for the determination of 4 metal antiknock agents, including tetraethyl lead, ferrocene, cyclopentadiene manganese tricarbonyl and methylcyclopentadiene manganese tricarbonyl in gasoline by gas chromatography-mass spectrometry was proposed. A certain amount of diethyl adipate (internal standard) solution was added into the gasoline sample to make its mass concentration to 2.00 mg·L^-1. After the instrument was stable, 1 μL was absorbed for determination. The 4 target compounds were separated on HP-PONA column under the temperature-programmed conditions and detected by the mass spectrometer. The retention time and mass spectra were used for qualitative analysis, and the characteristic quantitative ions combined with internal standard method were used for quantitative analysis. It was shown that the linear ranges of the working curves for 4 metal antiknock agents were 0.10-50.00 mg·L^-1, with detection limits (3S/N) in the range of 0.018 6-0.030 1 mg·L^-1. The 8 laboratories were selected, and test for precision was made on the samples at 7 spiked concentration levels. The results showed that there were no out-of-bound samples and laboratories, and the repeatability limits and reproducibility limits were given. Test for recovery was made on the blank samples at 3 concentration levels by addition standard method, giving results of 4 metal antiknock agents in the range of 95.1%-108%, and RSDs (n=6) of the recovery values were in the range of 1.2%-3.8%. This method and atomic absorption spectrometry (GB/T 8020-2015, SH/T 0712-2002 and SH/T 0711-2019) were used for the determination of lead, manganese and iron in 6 blank spiked gasoline samples, and the recovery values of this method were closer to 100%.