Abstract: The combination of gas chromatography (GC) and sulfur chemiluminescence detection (SCD) is a high effective method for analyzing sulfur compounds in hydrocarbon samples. A GC-SCD-FID combined instrument equipped with a PONA column was employed to determine sulfides in samples of synthesis diisobutylene (DIB). However, it was difficult to identify some SCD peaks due to solvent effects from DIB by the method. The influence of diisobutylene injection amount on the chromatographic peak properties of sulfide, disulfide and thiophene that may exist in petrochemical products was studied in detail. The retention time of sulfides without diisobutylene were predicted by sample dilution-extrapolation, and then confirmed by standard sample addition method. It was shown that the sulfide peaks appeared near the diisobutylene were greatly affected: The appearance time of diethyl sulfide peaks was 0.041 min earlier and the peak width increased by 2 times, the methyl tert-butyl sulfide retention time was prolonged by 0.443 min and the peak width increased by more than 9 times, the dimethyl disulfide peak time was prolonged by 0.377 min and the peak width was doubled, and the retention time of methyl sec-butyl sulfide was prolonged by 0.179 min. However, little effect on sulfide far away from the peak of solvent was found. Sulfides in diisobutylene samples identified by dilution-extrapolation method were mainly methyl tert-butyl sulfide, ethyl tert-butyl sulfide, di-tert-butyl sulfide, di-tert-butyl disulfide and other sulfides or disulfide containing isobutyl.

Key words: capillary GC, diisobutylene, organic sulfides, solvent effect, peak deformation, retention time shift