Valve interfaces

Figure 12.23 SFC-SFC analysis, involving a rotaiy valve interface, of a standard coal tar sample (SRM 1597). Two fractions were collected from the first SFC separation (a) and then analyzed simultaneously in the second SFC system (h) cuts a and h are taken between 20.2 and 21.2 min, and 38.7 and 40.2 min, respectively. Peak identification is as follows 1, tii-phenylene 2, chrysene 3, henzo[g/ i]perylene 4, antliracene. Reprinted from Analytical Chemistry, 62, Z. Juvancz et al, Multidimensional packed capillary coupled to open tubular column supercritical fluid chromatography using a valve-switcliing interface , pp. 1384-1388, copyright 1990, with permission from the American Chemical Society.

Multidimensional liquid chromatography encompasses a variety of techniques used for seunple separation, cleanup and trace enrichment [12,279-289]. A characteristic feature of these methods is the use of two or more columns for the separation with either manual or automatic switching by a valve interface of fractions between columns. These techniques require only minor modification to existing equipment, and of equal importance, enable the sample preparation and separation procedures to be completely automated. 

The equipment consisted of two Waters (Waters Corp. Milford, MA) M-45 pumps, a Waters 481 UV detector, a six-port Valeo sampling valve (A2L6P) with 0.08" holes in the valve body and rotor, a Rheodyne Model 7413 injection valve with a 1-pl loop, a valve interface box, and a Digital Equipment LSI-11/23-based microcomputer system. The microcomputer was used to control all valves, collect raw data from the UV detector, integrate the chromatogram, and store and plot results. 

V. Hakkinen, M. Virolaninen, et al., New on-line HPLC-GC coupling system using a 10 port valve interface, HRC CC J. High Res. Chromatogr. Chromatogr. Commun., 77 214-216(1988). 

Problem A safety instrumented function uses three analog transmitters as process sensors, a safety PLC and two remote actuated valves interfaced to the PLC with 24 VDC three way solenoids. What portion of the safety PLC is used in this safety instrumented function ... 

Jarrell, T, Riedeman, J., Carlsen, M., Replogle, R., Selby, T, Kenttamaa, H. (2014) Multiported Pulsed Valve Interface for a Linear Quadrupole Ion Trap Mass Spectrometer to Enable Rapid Screening of Multiple Functional-group Selective Ion-Molecule Reactions. Anal. Chem. 86 6533-6539. 

Ting, H., Hu, J.-B., Hsieh, K.-T., Urban, P.L. (2014) A Pinch-Valve Interface for Automated Sampling and Monitoring of Dynamic Processes by Gas Chromatography-Mass Spectrometry. Anal. Meth. 6 4652-4660. 

GC-MS analysis was carried out using an Agilent Technology 6890 gas chromatogram coupled to a 5973 mass spectrometer fitted with a CDS 1500 valve interface held at 250°C. Separation was performed on an SGE BPX5 column (30 m length, 0.25 mm ID, and 25 pm film thickness). Helium at column flow rate of 1.1 mL/min (constant flow rate) was used as the carrier gas. Injection was splitless and injector temperature 250°C. The GC oven temperature was held for 15 min at 30°C and then programmed at 4°C/min to 300°C.The final temperature was held for 9 min. 

SIA—CE has been successfully coupled to different detection techniques such as C4D [87], laser-induced fluorescence via a valve interface for online derivatization and analysis of amino acids and peptides [88] and ICP sector field mass spectrometer [89]. 

Figure 14-1 shows a typical feed cleanup system. The system s components are a settling drum, circulation pump, mix valve, interface level control valve, and wash liquid. The wash liquid, usually caustic or water, is contacted with a hydrocarbon stream. The mix valve provides the turbulence required for good contacting. The settling drum separates the two phases. The circulating pump returns the wash liquid to the mix valve. Finally, the interface level control valve sets the relative volumes of the wash liquid and hydrocarbon in the settler. 

The two main tools for establishing the loads on instrumentation and equipment are the scenario characterization (e.g., stuck-open relief valves, interfacing system pipe ruptures) and the deterministic analyses (in this case the aforementioned three-dimensional finite element analysis and MELCOR analysis). The conditions of interest are humidity, static and dynamic pressure, temperature, and radiation. All of these except radiation are readily calculated by MELCOR, though dynamic temperature and pressure estimation requires additional investigation using separate... 

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