A new application of headspace single-drop microextraction technique for compound specific carbon isotopic determination of gasoline range hydrocarbons

In this study, headspace single-drop microextraction (HS-SDME) coupled with gas chromatography–isotope ratio mass spectrometry (GC–IRMS), was employed to determine compound specific carbon isotopic values (δ13C) of gasoline range hydrocarbons. The reproducibility of the method was found to be satisfactory. By comparison with the δ13C values of the twelve target compounds determined using direct injection of their n-C16 solution, no obvious isotopic fractionation was observed during the HS-SDME procedures. Some parameters that could affect the carbon isotopic fractionation, such as ionic strength of working solutions and inlet split ratio, were examined. The results also suggest that these factors had no significant effect on the carbon isotopic determination of gasoline range hydrocarbons. The application of HS-SDME to a crude oil sample proved that this method could be a promising tool for the determination of carbon isotopic values of gasoline range hydrocarbons in oils or aqueous samples.