Advanced GC/ICP-MS design for high-boiling analyte speciation and large volume solvent injection

Abstract

A home made multifunctionary interface has been developed to connect a capillary gas chromatograph (GC) and an inductively coupled plasma mass spectrometer (ICP-MS). It can analyze high boiling analytes with a boiling point as high as that of C₂₆ n-paraffin (412 °C) at only 140 °C temperature in the transfer line. The design performs splitless large volume solvent injection to analyze sensitively very low and high boiling analytes in one run. The thin and flexible transfer line is heated by a combination of hot argon mixed with the GC effluent before passing the transfer line using a T-joint in the GC oven, and by electrical resistance heating. The flow through the transferline can be reversed to eliminate the solvent peak and to prevent graphite deposition onto the ICP-MS cones after large volume splittless injection. The detection limits for organotin (the propyl derivatives of all methyl and n-butyl, mono- and di-n-octyl, and all phenyltin), range from 68–250 fg absolute and are in the pg l⁻¹ range for 80 ml water samples extracted with 1 ml of solvent. The instrumental repeatablility is about 2% uncorrected and the linearity ranges to 5 ng absolute. This interface design is potentially useful for coupling more than one GC with one ICP-MS, for other plasma spectrometers (ICP-AES), for other types of large volume injection, and for high temperature (HT)-GC-ICP-MS.