ANALYSIS OF GEOPORPHYRINS BY HIGH-TEMPERATURE GAS-CHROMATOGRAPHY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY AND HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

High-temperature gas chromatography (HTGC) and high-performance liquid chromatography (HPLC) have been coupled to inductively coupled plasma mass spectrometry (ICP-MS) for the determination of geopophyrins from oil shales. A new, directly heated stainless-steel capillary interface was used to introduce the eluent into the ICP torch. The interface was robust, simple to install, programmable and introduced minimal loss (5-10%) in chromatographic efficiency. The HTGC-ICP-MS was used for rapid metal fingerprinting of the geoporphyrin fractions. Cobalt, chromium, iron, nickel, titanium, vanadium and zinc metalloporphyrins were fingerprinted. For quantitative analysis HPLC-ICP-MS was preferred. Quantitative data obtained by HPLC-ICP-MS and HPLC with UV absorption detection of nickel geoporphyrins from Julia Creek and Serpiano oil shales showed good agreement. Levels of nickel porphyrins were in the range 15-120 mug g-1 in the samples analysed. The potential for multi-element, multi-isotopic detection is clearly illustrated using up to ten elements/isotopes virtually simultaneously.