Mass resolving power is one of the key features of Fourier transform ion cyclotron resonance mass spectrometry (FT‐ICR MS), which enables the molecular characterization of complex mixtures. Quadrupole (2ω) detection provides a significant step forward in FT‐ICR MS performance, as it doubles the resolving power for a given signal acquisition time. Whether this 2ω detection technique truly substitutes for a higher magnetic field remains unknown however. In this study, a residue oil sample was characterized using both a 2ω 7 Tesla FT‐ICR and a 15 Tesla FT‐ICR instrument, and analytical figures of merit were systematically compared. It was shown that 2ω 7T FT‐ICR MS provided comparable performance in the deep profiling of the complex oil sample, with better signal intensities and reproducibilities for absorption‐mode processing. The 15T FT‐ICR MS gave more precise measurements with better estimates of the sample's elemental compositions. To the best of our knowledge, this is the first published study, which thoroughly compared the performance of 2ω detection on a low magnetic field instrument with that of a high magnetic field FT‐ICR‐MS.
Calcium carbide was successfully synthesized by carbothermal reduction of lime with coke at 1973 K for 1.5 h. The effect of potassium carbonate as additive on the composition and morphology of the product was investigated using X-ray diffraction and scanning electron microscope. Addition of potassium carbonate increased the yield of calcium carbide. The sample in the presence of potassium carbonate generated acetylene gas of 168.3 L/ kg, which was 10% higher than that in the absence of potassium carbonate. This result confirmed the catalytic effect of potassium carbonate on the synthesis of calcium carbide. A possible mechanism of the above effects was that the additive, which was melted at the reduction temperature, dissolved CaO and so promoted the contact between CaO and carbon, which was essential for the solid-solid reaction to form calcium carbide.
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