Multi-Element Detection of Organometals by Supercritical Fluid Chromatography with Inductively Coupled Plasma Mass Spectrometry Detection

Organometal compounds of arsenic, antimony, and mercury are speciated using supercritical fluid chromatography with inductively coupled plasma mass spectrometric (ICP-MS) detection. The multielement capability of ICP-MS for transient signals is examined by detecting five compounds containing all three elements in a single chromatographic injection. The results obtained are compared with those obtained from flame-ionization detection (FID). Trimethyl arsine is not distinguished from the solvent peak when FID is used because it coelutes with the solvent, whereas trimethyl arsine is detected when ICP-MS is used because of its element-selective nature. The detection limits obtained by ICP-MS are 2-3 orders of magnitude lower than those obtained by FID. Determination of isotope abundance is also demonstrated for triphenyl antimony and diphenyl mercury compounds.