The National Forensic Science Technology Center (NFSTC) evaluated the CT-1128 portable gas chromatograph-mass spectrometer (GC-MS) manufactured by Constellation Technology, in order to determine the suitability of this chemical-detection system for use in the analysis and identification of forensically relevant chemical compounds.
The evaluation concludes that the instrument performed adequately for the analysis and identification of drugs of abuse, ignitable liquids, and explosives. The instrument is capable of performing real-time snapshot analysis of unknown spectra, allowing for the identification of the unknown compound through direct spectral library comparison. The CT-1128 has an integrated heater mixer component located in the exterior housing of the instrument that allows for the extraction of volatile compounds from either liquid or solid matrixes. The instrument uses a small internalized rough pump and two turbomolecular pumps that are housed within the instrument, eliminating the need for a heavy external vacuum pump and lengthy pumpdown times. In offering recommendations for improvement, the evaluation notes that the operation of the CT-1128 requires the use of two separate software platforms: Chemstation/E and Constellation Technology GC Software. Integration of the two separate software platforms would make the system more functional and user friendly. Also, the performance of a split sample injection on this system requires an awkward and time-consuming manual process with the use of the adjustable purge flow regulator and a flow meter. A programmable flow control system within the GC method software would be a more suitable means of performing this function. This report also outlines training requirements for users, as well as recommendations for ensuring the health and safety of users. 3 figures