24-channel peristaltic pump

Figure 10 shows the instrumental setup used to implement the APP-CLS approach. It consists of (a) a CSTR that is a thermostated 10-mL glass reaction vessel accommodated in a commercially available spectrofluorimeter (a Hitachi F2000 model in this case) (b) a four-channel peristaltic pump with three channels used to dispense the reagent solutions and the fourth to keep the volume of the reaction mixture in the CSTR constant the three reagent solutions are as follows (1) 0.15 M hydrogen peroxide (2) 0.15 M sodium thiocyanate, 0.15 M sodium hydroxide, and 1.95 x 10 3 M luminol and (3) 6.0 x 10 4 M copper(II) sulfate ... 

The FIA system consisted of TMI modules (Tecniques Mesura Instrumentacio), a five-channel peristaltic pump, an eight-channel injection valve, an eight-channel distributed valve, and a colorimeter connected to an interface and to an IBM-PC microcomputer. A specific application software, Qcontroll , was used for data acquisition, with a continuous historical trend, and a scheduled control program for sequential analysis. In a previous scheme as in Fig. 1, free enzymes were used and the whole system was calibrated for a linear range of 0.05-1.0 g of ethanol/ L of standard ethanol solutions, and the product of the reaction was passed through the colorimeter. 

Continuous, batch, and flow injection modes of hydride generation have been used successfully [39-41]. In the commonly used continuous mode the sample and sodium borohydride solutions are pumped by using a dual-channel peristaltic pump into a mixing chamber. The volatile hydride gas and hydrogen are carried into the plasma with a flowing argon gas and the excess liquid is directed to the drain. 

P. Skafte-Pedersen, D. Sabourin, M. DufVa and D. Snakenborg, Multi-channel peristaltic pump for microfluidic applications featuring monohthic pdms inlay. Lab on a Chip, 9(20), 3003—3006 (2009). 

The ICP source subsystem incorporates its own internal microcomputer and memory in order to execute the controller s commands. The RF power supply Is under computer control. Likewise, all of the argon flows, the ignitor, peristaltic pump and safety interlocks are directly controlled by the system computer. The RF power output Is stable to less than 0.01 over 1 h of operation. The nebulizer argon flow is controlled through a thermostated mass flow controller to ensure long-term stability. The uptake rate of the two-channel peristaltic pump Incorporated within the source subsystem Is variable by the system controller. 

Both to ascertain the role of the catalyst and to demonstrate the efiFects of pH, experiments have been performed at controlled levels of conversion of formaldehyde in a continuously stirred tank-reactor. Figure 2 shows such a simple reactor, in which the feed streams are segregated and the slurry of calcium hydroxide is kept agitated. Commercial, 37-percent formaldehyde solution is fed in from a separate reservoir, and a multiple-channel, peristaltic pump permits independent variation of the feed rates. 

However, an important demerit of piston pumps, which limits their versatility, is the small number of available channels (usually two). A piston pump with an equal number of channels as an eight-channel peristaltic pump would be much more expensive and bulkier than the latter. Piston pumps are therefore often supplemented by peristaltic pumps, using the laner for purposes where flow-rate stabilities are less critical, such as filling samples into a sample loop. 

Single or dual multi-channel peristaltic pumps... 

FI system consisting of a 5-channel peristaltic pump equqtped with tygon pump tubes a 4 4 channel injector valve 1 mm i.d. FIFE reaction coils and connection lines connected with a Chemifold and a gas-liquid separator trf one of the types shown in Fig. 5.4 a and b. 

Continuous Hydride Generation. In the continuous or FIA hydride generation method the sample and reagent solutions are continuously pumped, usually by a multi-channel peristaltic pump, into a mixing chamber where... 

Sample and buffer solutions were pumped by two 2-channel peristaltic pumps (Ismatec SA, Zurich, Switzerland), using tygon tubes 0.51, 1.42 and 1.52 mm inner ameter (Bioblock, Illkirch, France). 

A 32-channel peristaltic pump can be used, enabling 15 duplicate test samples and a duplicate control sample (e.g. a stable local groundwater derived tap-water) to be tested simultaneously. This allows various experimental designs to be used in investigating the plumbosolvency characteristics of test waters, examples being ... 

Fig. 9.9 Experimental set-up 1 test module, 2 heater, 3 electrical contact, 4 micro-channel, 5 Pyrex, 6 peristaltic pump, 7 and 8 pressure and temperature measurements, 9 cooler, 10 reservoir, 77 IR camera, 72 microscope, 13 high-speed video camera, 14 PC, 75 synchronizer, 16 video recorder. Reprinted from Peles et al. (2001) with permission...

The flow-through cuvette that is used for the four-channel sensor is made from Perspex and is 31-mm long and 7-mm wide. It has four flow chambers each with a volume of 1.2 pi (6 mm long and 3 mm wide), see Fig. 10.8. Each chamber of the cuvette has an inlet and outlet that are connected via a tubing system with the sampling reservoirs, which contain solutions to be monitored, and to the waste, respectively. Samples are flowed by means of a peristaltic pump (Ismatec... 

In a practical FIA system, peristaltic pumps are usually used since they have several channels, and different flow rates may be achieved by selection of a pump tube with a suitable inner diameter. 

In addition to the above manufacturers, suitable peristaltic pumps with a minimum of 12 tube channels, such as the Ismatec IPC-16 and IPC-24 versions (cost 2000+), are obtainable from ... 

The mixing ability of microfluidic systems was tested using a rotary pump, a circular channel with inputs and outputs that can be peristaltically pumped, opeued, and closed. It was found that after only a few minutes of active mixing (due to pumping), a uniform mixture of particles is obtained that would have taken hours to achieve by diffusion. This is also useful for accelerating diffusion-... 

Fig. 1. Free enzymes FIA system 1, enzymes and reagents solution 2, sample solution 3, buffer solution 4, peristaltic pump 5, three-channel valve 6, six-channel injection valve 7, colorimeter 8, computer 9, waste 10, coil.

Fig. 3. Proposed integrated FIA system, with microreactor packed with immobilized AOD 1, buffer solution 2, sample solution 3, horseradish peroxidase and reagents solution 4, eight-channel distribution valve 5, coil 6, peristaltic pump 7, colorimeter 8, computer 9, micro reactor 10, eight-channel injection valve 11, waste.

FIGURE 3.27 An elastomeric peristaltic pump using three valve control channels. The fluidic channel is 100 pm wide and 10 pm high. Dimension of microvalve control channels = 100 pm by 100 pm by 10 pm applied air pressure = 50 kPa. Peristalsis was typically actuated by the pattern 101, 100, 110, 010, Oil, 001, where 0 and 1 indicate valve open and valve closed, respectively [167]. Reprinted with permission from the American Association for the Advancement of Science. 

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