The GC-ICP-MS interface is designed for use with the Agilent 7890 gas chromatograph. The interface hardware consists of a torch adaptor and demountable GC torch with heated injector and a novel heated transfer line to interface the GC to any of the Agilent 7700 Series ICP-MS models. The fully programmable Agilent 7890 GC can be used for research or routine analyses that require multiple columns (capillary or packed columns) or valves, specialty inlets, over a broad temperature range. Because GC separations typically give much shorter signal peaks than LC separations, it is important that the ICP-MS is able to acquire data quickly. The new, fast simultaneous dual mode detector of the Agilent 7700 is perfectly suited to GC signals since, unlike older detector designs, the acquisition speed is equally fast (<100us minimum dwell) regardless of whether the detector is acquiring in pulse count or in analog mode. Coupling and uncoupling the GC and ICP-MS has been made quick and easy, to maintain flexibility in the laboratory. The non-rigid GC transfer line permits easy alignment and adjustment of the torch for system optimization, so the GC interface does not hinder the automatic torch positioning routine of the Agilent 7700 software. The torch has been specially designed for ease of installation and reliability. The transfer line can be uniformly heated to 300°C if required, thereby eliminating cold spots in the column. The presence of cold spots, especially at the connection point to the torch, must be avoided for successful analysis of high boiling point compounds, which would otherwise condense on the walls of the transfer line. Using the Agilent 7700 ICP-MS as a detector for GC gives fast multi-isotope or multi-element analysis and extremely low detection limits for most elements. The analytical performance of the new interface was evaluated by analyzing a mixed organotin standard. The analysis was completed in less than 12 minutes with a detection limit for tributyl tin (TBT) of 5.9 ppt (Figure 1). This data demonstrates that the GC-ICP-MS is capable of rapid and sensitive detection of organotins. The new interface has also been proven for more difficult applications such as S speciation in fuels and the separation of polybrominated diphenyl ether (PBDE) flame retardants.
Figure 1. Chromatogram of a 1 uL injection of a 10 ppb mixed organotin standard
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