Exhibit no. 695

Moving belt is a transport type LC/MS interface developed in the late 1970s. It consisted of an endless belt, which received effluent from an LC column. The moving belt interface made it possible to combine liquid chromatography with EI, CI, and FAB mass spectrometry.

The exhibit is a 0.16” (4 mm) wide and 44” (112 cm) long polyimide belt for an interface, which was used with a sector mass spectrometer ZAB EQ (VG Analytical, Ltd., 1986). The LC eluent was deposited on the moving belt by a spray depositor. The belt then passed through three tunnel seals in a two-stage vacuum lock where the pressure was reduced, and finally through another seal into the ion chamber. The sample in the ion chamber was evaporated by a heater situated immediately behind the belt. As it returned, the belt passed over a clean-up heater, which removed trace of material not evaporated in the ion chamber. The belt was driven by a stepping motor and its speed was adjustable in the 0.2 - 3.2 cm/sec range. The transfer efficiency was 30 – 80 %, depending on the conditions. When a new belt was fitted to the interface, the background signals were unacceptably high. It was necessary to condition the belt, usually for 24 hours, with the source temperature at 300 °C. Large background peaks remained in the low mass region even after conditioning, and therefore the use of the belt below m/z 120 was not recommended. The exhibit is made of Kapton and it was manufactured by Pacific Belting Industries Inc. from Los Angeles, CA.

Wikipedia: LC/MS


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