Split range mode

This can be thought of as an enhanced split-range scheme. Aside from the fast and accurate temperature cycles that result, the beauty of this concept is that the operator has only one controller to deal with. In addition, whenever the controller mode is switched to manual, the output ramped up and the steam accordingly comes on, the second algorithm shuts down the coolant, drains the jacket, and checks any other interlocks. 

Different options are available for LC-MS instruments. The vacuum system of a mass spectrometer typically will accept liquid flows in the range of 10-20 p,L min-1. For higher flow-rates it is necessary to modify the vacuum system (TSP interface), to remove the solvent before entry into the ion source (MB interface) or to split the effluent of the column (DLI interface). In the latter case only a small fraction (10-20 iLrnin ) of the total effluent is introduced into the ion source, where the mobile phase provides for chemical ionisation of the sample. The currently available commercial LC-MS systems (Table 7.48) differ widely in characteristics mass spectrometer (QMS, QQQ, QITMS, ToF-MS, B, B-QITMS, QToF-MS), mass range m/z 25000), resolution (up to 5000), mass accuracy (at best <5ppm), scan speed (up to 13000Das-1), interface (usually ESP/ISP and APCI, nanospray, PB, CF-FAB). There is no single LC-MS interface and ionisation mode that is readily suitable for all compounds... 

Analytical Methods. All of the sorbent extracts were analyzed by using GC-MS. The solutions were chromatographed on a 30-m X 0.32-mm i.d. Supelcowax 10 capillary column with a film thickness of 1 /um (Supelco). The Supelcowax 10 is a Carbowax PEG 20 M bonded-phase capillary column. The instrument conditions were as follows injector, 250 °C separator oven, 250 °C column over initial, 40 °C programmed to 250 °C at 6 °C/min linear velocity of helium carrier gas, 35 cm/s at 40 °C column head pressure, 6 lb/in.2 mass range, 33-333 amu scanned in 1-s intervals. Two-microliter aliquots were injected in the split mode at a 10-to-l split ratio. A typical chromatogram appears in Figure 1. 

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