There have recently been great demands to develop flow injection analysis (FIA) and other flow analysis methods for slow flow rate systems. Goto et al.l have employed an economical automated method using continuous micro flow for the determination of mercury in environmental analysis. Micro flow analysis stream (less than 100 µl min 1) is suitable for continuous monitoring because of the small amount of reagents required. We have also proposed an S4 system designed for the basic improvement of FIA instruments.2 Combinations of a narrow (i.d. sO.5 mm) and short (~10 cm) reaction tube, a small-volume flow cell (8 µl) and small flow rate (50.05 ml min 1) gave better sensitivity for the determination of macromolecules in biotechnology assays. Very recently, we have applied this system as a capillary stream sensor to the determination of potassium ion.3Moreover, as biosensing devices have become smaller", stable pumping at a very small flow rate would be strongly desired through FIA use. However, it is not easy to buy such a stable pump commercially, although various pumping mechanisms are designed for the improvement of FIA apparatus. We therefore present a double plunger micropump with linear cam mechanism having very short plunger strokes, in order to attain higher sensitivity and precision in S4-FIA determination.
ExperimentalThe pumping properties were examined using the equipment for investigating dispersion behavior of the injected sample solute in laminar capillary flow system.5 The equipment for observing experimental laminar tube flow was applicable for the experimental evaluation of mixing process between colored sample solution and water in a tube since light source and photodiode are placed parallel to the outside walls of tubing. Mean concentrations of resulting solutions after mixing over a cross section can be measured sensitively.The base lines and mixing profiles in a short tube were investigated at the down flow using the microphotometric detector. The signals were recorded after 4X104 M Basic Blue 3 (BB3) dye and distilled water were fed by each double pump and mixed.A sample injector (Sanuki Model SV1-6U7, 8 µl) and a connector (less dead volume) were set to the flow equipment when the peak profiles were investigated. Tubing lengths between sample injector and connector were shortened as much as possible. A dilute solution of BB3 was used as the sample slug.
Results and DiscussionThe mechanical specifications of the micropump presented here are listed in Table 1. It covers a very small flow rate region, 5 -130 µl/ min in total, as required by the above systems. Other pumps cannot meet this requirement. The micropump is a double plunger type with linear cam mechanism; the cam systems show a linear discharge curve.The micropump features very short strokes (0.5 mm), a small plunger diameter (2.5 mm) to provide constant reciprocal feeding of very small amounts of solutions (2.45 µl/ stroke each) and has a characteristic phase shift of 1800.A double plunger pump with linear cam mechanism is controlled...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.