Bore liquid flow rate

Figure 22 SEM of the cross section of the wall of a PPO hollow fibre. (Bore liquid flow rate=lml/min)...

Case Concentration of PPO in polymer solution (wt %) Air gap (cm) Bore liquid flow rate (ml/min) Polymer solution flow rate (ml/min)... 

The coupling of LC with mass spectrometry is not as straightforward as a similar combination of GC with MS. There are several fundamental differences in the operating environment of HPLC and mass spectrometry. The first mismatch is the solvent flow rate. The separation in conventional wide-bore analytical columns is accomplished at liqnid flow rates of 0.5 to 1.5 mL/min. Unlike GC/MS, this liqnid produces a gas flow too large for safe operation of the mass spectrometry vacnnm system (10 to 10 torr). For example, 1.0 mL of water will pro-dnce about 1.0 x 10 m of gas load when introduced in a mass spectrometer at 10 torr pressure (see Example 5.3). Liquid flow rates below 10 xL/min can be accepted safely by a mass spectrometry system. Another problem is the... 

On-line coupling between a gas chromatograph and an atomic spectrometry detector is fairly simple. Typically, the output of the CG capillary column is connected to the entrance of the atomisation-ionisation system simply via a heated transfer line. When separation is performed by liquid chromatography (EC), the basic interface is straightforward a piece of narrow-bore tubing connects the outlet of the EC column with the liquid flow inlet of the nebuliser. Typical EC flow rates of 0.5-2 ml min are within the range usually required for conventional pneumatic nebulisation. 

The liquid chromatograph used 1n this study consisted of a Cheminert Model CMP-2K (Laboratory Data Control, Riviera Beach, FI.) which is capable of a maximum flow rate of 2 ml/min at a maximum pressure of 500 PSI. This pump has all liquid contact parts limited to glass, teflon or KEL-F materials to reduce corrosion to a minimum. The Injection valve is a Laboratory Data Control Model SU 8031 slider valve with a 0.5 ml sample loop. The injection valve is located at the top of the column to minimize dead volume. The separating column is a Laboratory Data Control type MB glass column, 30 cm long with a 2 mm bore capable of a maximum pressure of 500 PSI. The column is packed with surface sulfonated cation exchanger resin prepared in this laboratory in the following manner. 

The last flow meter that we will address is the rotameter. This meter is relatively inexpensive and its method of measurement is based on the variation of the area through which the liquid flows. The area is varied by means of a float mounted inside the cylinder of the meter. The bore of this cylinder is tapered. With the unit mounted upright, the smaller portion of the bore is at the bottom and the larger is at the top. When there is no flow through the unit, the float is at the bottom. As liquid is admitted to the unit through the bottom, the float is forced upward and, because the bore is tapered in increasing cross section toward the top, the area through which the liquid flows is increased as the flow rate is increased. The calibration in rates of flow is etched directly on the side of the cylinder. Because the method of measurement is based on the variation of the area, this meter is called a variable-area meter. In addition, because the float obstructs the flow of the liquid, the meter is an intrusive meter. 

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