[en] Introduced in 1996, the Agilent (Hewlett Packard) HP 6890/5973 GC/MSD system is the latest of the bench-top GC/mass spectrometry (MS) family. Started with the HP 5970 MSD, introduced in the mid-1980s, has provided small/medium size laboratories with the power of a true MS that provides selectively and library-searchable capability. This paper presents study results on instrumental sensitivity achieved with the new MSD, with examples illustrating trace-level analysis of semi-volatile compounds such as PCB and Dioxins. Investigations were carried out to study the effect of some operational parameters such as ionisation energy, dynode voltages and dwell time. In the standard electron impact selected ion monitoring (SIM) mode, the new MSD can provide sub-picogram level sensitivity for chlorinated hydrocarbons. In scan mode, under optimal condition, the system can generate library-searchable spectra from sub-nanogram quantity of analytes. This sensitivity level rivals traditional GC with selective detectors such as electron capture detector but at the same time possesses the advantage of computerised library search against a database of over 100 thousand spectra. The relatively compact size makes the system practical in a mobile laboratory, providing qualitative as well as quantitative data in spill emergencies analyses

[en] A novel furnace throat structure was designed to reduce dust particle concentration in the flue gas emitted from the copper smelting industry. A two-stage turbulence model of the furnace throat based on the RNG k-ε model combined with the stochastic trajectory model was developed to analyze the gas flow and particle trajectories in this furnace throat structure. The resulting turbulent flow fields and particle trajectories under different operating conditions were shown and discussed. It indicates that the furnace throat plays an important role in separating the dust particles from the flue gas by applying centrifugal force and subsequent resistance force. Moreover, the effects of the radius of the inner flue, the number of the spiral plate, and the number of the spiral plate turns on the particle collection efficiency were analyzed to optimize the throat structure. The simulation results show that the furnace throat with inner flue radius of 0.05 m, two spiral plates, and two spiral plate turns has the highest particle collection efficiency. Furthermore, a series of experimental tests were conducted to validate the accuracy of the simulation results, and the measured experimental data show a good correlation with the numerical results.