Programmer high pressure

There are two types of gradient programmer. In the first type, the solvent mixing occurs at high pressure and in the second the solvents are premixed at low pressure and then passed to the pump. The high pressure programmer is the simplest but most expensive as it requires a pump for each solvent supply. There can be any number of solvents involved in a mobile phase program, however, the majority of LC analyses usually require only two solvents but up to four solvents can... 

P 32] Pyrene (20 mM), 1,4-dicyanobenzene (40 mM) and sodium cyanide (1 M) were reacted in propylene carbonate and water. A 100 pi solution of pyrene (20 mM), 1.4-dicyanobenzene (40 mM) in propylene carbonate and a 100 pi solution of sodium cyanide (1 M) in water were fed by programmable dual-syringe pumps via fused-silica capillary tubes into a micro-channel chip [29]. Both solutions were fed with equal flow velocity. A 300 W high-pressure mercury lamp was used as light source. After passing an optical filter made of a CUSO4 solution, the whole chip was irradiated after formation of a stable oil/water interface inside. The oil phase was collected at the exit. 

CrystalSulf A process which uses a nonaqueous solvent/catalyst system to remove sulfuric acid from high-pressure natural gas. This project, part of the GRI Basic Research programme, has been conducted by Radian Corporation. 

Chromatograph type and manufacture LC 210 high pressure pumps, programmer 200, ... 

Figure 6.23. High-pressure DTA system described by Williams and Wendlandt (131. l ) Schematic diagram of apparatus. A. high-pressure DTA cell B. T T Controls Company Model No. TPC-2000 temperature programmer C Du Pont Model 900 recording module D, relief valve E, valve F. pressure gauge G. gas pressure regulator H. gas cylinder, b) Schematic diagram of DTA cell. A. furnace chamber B. high-pressure connectors for furnace wires and thermocouples. C. furnace D. DTA sample and reference holders E. gas outlet tube F, Buna-N O-ring G. base plate H. Conax connector for thermocouple wires 1. gas inlet-outlet connector.

Fig. 9. Waters Model 660 solvent programmer, a, a = solvent reservoirs, b, b = dual-head pumps, c, c = pressure sensors, d = solvent programming manifold, e = high-pressure noise filter, f = to column.

The main focus of the measurement programme was the rheological measurements with the high-pressure capillary viscometer. In addition, a number of measurements were performed with the aim of permitting statements about the dispersion state (pyrolysis, microscopic investigations) and determining (conductivity measurements). 

In the FIA system, peristaltic pnimp (ISMATEC ITC, Switzerland) 0.50 mm i.d. PFTE tubing was used to propel the samples and reagent solutions. Samples were injected into the carrier stream by a 7125 model stainless steel high pressure Rheodyne injection valve provided with a 20 )xL loop. The absorbance of the coloured complex formed (Xmax 415 nm) was measured with a UV-Visible spectrophotometer equip>p)ed with a flow-through micro cell (Spectra SYSTEM UV 3000 HR, Thermo Separation Products, USA), and connected to a compniter incorporated with a PCI000 software programme. 

Figure 3 is a schematic diagram of the equipment that is used for precipitation, filtration and washing, all at a high pressure. It consists of a CO2 delivery system and an autoclave with a volume of 400 ml. The vessel is equipped with baffles, a stirrer and a water-jacket for heating and cooling. The bottom of the autoclave contains a filter plate with a pore-size of 10 micrometers. The carbon dioxide flow to the precipitator is controlled by an air operated needle valve in combination with a pressure transducer and a programmable controller to impose a predetermined pressure profile. 

The solvent programmer is an apparatus that allows the composition of the mobile phase to be changed, in a defined manner, over a defined period of time, and is normally controlled by the chromatograph computer. There are basically two types of gradient programmer, one that mixes the solvents at high pressure, prior to the column and the other that involves solvent mixing that occurs at low pressures, prior to the solvent pump. 

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