Injection dual-valve

J. Skrlikova, V. Andruch, H. Sklenarova, P. Chocholous, P. Solich, I.S. Balogh, A novel dual-valve sequential injection manifold (DV-SIA) for automated liquid—liquid extraction. Application for the determination of picric acid, Anal. Chim. Acta 666 (2010) 55. 

However, since the suction gas to the compressor would then be hotter than its normal slightly superheated condition, the compressor may overheat and the discharge gas become too hot for correct and safe working. This form of capacity reduction is usually combined with a liquid injection valve, thermostatically operated, which introduces liquid also into the suction to keep it cool. The fitting of dual interdependent controls of this sort, both of which have inherent fail-unsafe possibilities, should be approached with caution. 

High Performance Liquid Chromatography. All separations were performed using an Altex Scientific (1780 Fourth Street, Berkeley, CA 94710) Model 320 Advance Research Chromatograph, consisting of a model lOOA dual piston analytical pump, a Model 153 UV detector, a Model 210 injection valve, and a Model 155 recorder. The columns (600 x7.5mm) evaluated were the Spherogel TSK-SW-2000 and SW-3000 (Altex). Unless otherwise stated, all separations were carried out at 23 - 25 . 

An eight-port or a ten-port valve with dual matching sample loops is generally used for automated comprehensive 2DLC so that solute is injected repetitively into the... 

As pointed out above, IC is a well-established method for the analysis of inorganic anions and has become the method of choice in many application areas. Many techniques are available using singlecolumn [46] or dual-column systems with various detection modes. IC can be used both for analytical and preparative purposes. Large sample volumes, up to 1300 pul, can be injected to determine trace anions and cations and to attain detection limits of 10-400 ng/1. For determinations at a pig/1 to mg/1 level, a sample size of 10-50 xl is sufficient. Preconcentration is necessary for lower concentrations (an additional column, a sample pump, an extra valve and an extra time are the disadvantages of this approach [47]). With an IEC column and isocratic... 

HPLC The sample was injected on to an ACS Model LC750 chromatograph with dual pumps (Applied Chromatography Systems Ltd, Luton, Beds, U.K.) by means of a loop injection valve,... 

FPLC components (two P 500 pumps, V7 injection valve, gradient controller, UV-1 detector, Frac-100 fraction collector, 50 mL Superloop [Pharmacia], dual-channel chart recorder, or similar components). 

These conversions operated safely without flashback but all the performance factors depending on engine power were poor. Eventually, two solutions to the flashback problem were found. Either dual path mixing channels or injection at the intake valve allowed the design of hydrogen-fueled engines suitable for routine use. 

M. Blanco, J. Coello, H. Iturriaga, S. Maspoch, J. Riba, Modification of a commercial dual channel valve to be used in a stopped-flow injection analysis system, J. Flow Injection Anal. 7 (1990) 3. 

Fig. 6.19 Manifolds used for simultaneous determinations with a single detector, (a) With splitting and merging points (b) with dual injection and one merging point (c) reversed FIA with sequential injection of reactants (d) injection of a large sample volume and formation of two reaction zones (e) manifold with two serial flow-cells accommodated in a spectrophotometer (f) closed-open system. R, reagent S, sample D, detector W, waste SV, selecting valve.

Fig. 15.8 FIA configurations for the off-line speciation of chromium, (a) With a splitting point (A) and a dual-beam detector (a.1) with two cells aligned with the light path (a.2) with a merging point prior to a single flow-cell (a.3). (b) Sequential determination with the aid of a selecting valve. DPC diphenylcarbazide Ox oxidant [Ce(IV)] q flow-rate Vi injection valve L and 0 reactor length and inner diameter V2 selecting valve W waste. (Reproduced from [37] with permission of Elsevier).

FIG. 9—Plot of sulfur response as a function of concentration for a liquefied butane matrix over the range of approximately 1.2—1200ppm PUS injection valve and Dual Plasma SCD with LTMGC module at 250°C. 

Fig.2 (c)(d) Applications of the 8-channel multifunctional valve, c, merging zones application in which injected sample and reagent zones merge at point M. d. application for dual sorption column preconcentration with which a second valve is required to elute the two columns sequentially. V, V/, multifunctional valves V//, 2-way valve ... 

To allow for dual-fuel operation, some modifications on the engine itself and its subsystems have been carried out. For example the injection valves for the external mixture formation, the hydrogen supply rail and the ignition system. A concept... 

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