Three-Position Device

Overall, the development of the three-position microfabricated device coupled to ESI-MS-MS was a success. However, the throughput of the device was limited to one sample at a time. Therefore, our next step was to explore different designs for multiplexed devices. 

---

Over the years, many different approaches based on these two basic principles have been developed.4 9 We decided to focus on developing an approach to transfer analytes by coupling capillary tubing with electrospray ionization devices. From this basic design principle, we were able to develop a simple three-position device for the analysis of proteomic samples by mass spectrometry.7,10 We developed this principle further into an automated nine-position device,6 and to perform frontal analysis separations of peptides.11 This chapter reviews these early developments in coupling microfabricated devices to mass spectrometers. 

As the next syntactic device let us consider three-position descriptors, each position of which provides information of a particular kind. These pieces of information are firmly associated in one term, which creates an especially close connection between them. Such terms have proved successful in the fragment code GREMAS for chemical structures and also for the documentation of patent literature in the fields of plant protection and agriculture (see Figure 5). 

Figure 4 shows a schematic of the detector positions in the CARPT Facility which consists of the column, the detector support structure and the signal processing and data acquisition system. The set-up consists of 16 Nal detectors (2.54 x 2.54 cm crystals) positioned around the bubble column at known locations. The column makes use of a Plexiglass plenum which can accommodate test sections of various diameters. A stainless steel porous plate distributor with an average pore size of 40 pim is sandwiched between the two sections. A positioning device was fabricated and attached to the top of the column for calibration purposes. Air to the column is supplied by a compressor and the flow rate is monitored by three parallel rotameters. 

In our days the SECM is recognized as the member of numerous scanning probe microscopic techniques. Similarly to the other scanning probe microscopic methods, it employs a microsized measuring probe, three-dimensional positioning devices, computerized data collection, and evaluation. Special feature is, however, that in SECM electrochemical microprobes are used. 

The Safety Setting Input Units (SSIUs) are three redundant devices, one for each trip unit. Each SSIU has a front panel, which provides as many sets of thumbwheels as Safety System Settings (SSS) are required by its related trip unit. Appropriate values for these SSS are defined by an authorised operator through these thumbwheels and they are read into RAM only once every time the trip unit is power-on. Each SSIU has a panel-door, which is mechanically locked in its closed position, to allow no changes of its SSS while its related Trip Unit is operating. In case this mechanical protection is overridden, the unlock SSIU shall power-off its related trip unit. 

The swan neck adapter of Fig. II, 56, 12 is useful for distillations as it permits the use of a capillary tube (held in position by a short length of heavy-walled rubber tubing) not sealed to a ground joint. It may also be used for inser tion of a thermometer or a gas-inlet tube in the narrow neck and a reflux condenser into the ground joint this device virtually converts a three-necked into a four-necked flask. Common sizes are cone fil9, 24, 29, or 34 socket 19, 24 or 29. 

---