Multiplexed data processing

Control of the HPLC pump, the autosampler, and the MS is ensured by Masslynx 3.5 software. After optimization of the measurement conditions, a list of process measurements is setup (sample list), and the desired HPLC and MS steps are called upon. After a measurement, the ESI source is automatically brought to room temperature (shut down). Using 96-microtiter plates, 576 samples can be processed per measurement. The chromatograms are integrated by the software packages Quanlynx and Openlynx and exported as an Excel table. A macro is used to calculate the absolute intensities and therefore the ee and the conversion. The E values in kinetic resolution are automatically calculated with the formula of Sih [12]. Data processing is done with the Openlynx Browser. The overall process occurs continuously and enables analysis of up to 10000 samples per day, provided that the 8-channel multiplexed sprayer system is used [20b]. It is also possible to use 384-well micro titer plates. Systematic optimization is required for each new compound. 

Figure 8.2.6 H spectra of four different samples (500 mM in D2O) obtained by using the subtraction method. These represent the post-processed spectra of (a) methanol (4.7 and 3.2ppm), (b) f-butanol (4.7 and 1.1 ppm), (c) water (4.7ppm) and (d) acetonitrile (1.9ppm), and (e) the spectrum of the four different samples before data processing. Reprinted from MacNamara, E., Hou, T., Fisher, G., Williams, S. and Raftery, D., Multiplex Sample NMR an approach to high-throughput NMR using a parallel coil probe , Anal. Chim. Acta, 397, 9-16, copyright (1999), with permission of Elsevier Science...

Novel sieving media and acceleration of electrophoretic runs coupled with suitable data processing are likely to provide excellent approaches to DNA sequencing by multiplexed CE. The technology can be readily scaled to 1024 capillaries, which is a convenient number for available array detectors. Such a system can be optimized to accelerate the sequencing process enormously. 

In most systems the interface contains a switching device to multiplex other signals from the MS such as the total ionization and magnetic field sensing voltages used in certain aspects of data processing. Directed by an operator from an input terminal, the data are processed in the CPU under the control of programmes stored in a peripheral device. 

True paraUehzation of analytical processes has, so far, not been very successful. In such set-ups, only the separation module (in general the column) is set up in parallel, while solvent delivery, injection, detection, and data processing are multiplexed. These systems will no longer be as simple in operation and maintenance as the cloned systems. 

The device was manufactured as two parts the first part is a disposable silicon chip - with the electrochemical cells arrays. The sihcon chip was wire bonded to a special printed circuit board (PCB) platform, which was directly connected to the data processing units. The second part of the device is reusable, which includes a multiplexer, potentiostat, temperature control and a pocket PC for sensing and data analysis (for more details see [5]). This design enables performance of multi experiments simultaneously and each electrochemical cell can be measured independently. The total weight of the entire system is -900 g, making it ideal for medical applications. 

Data processing. The microprocessor functions according to the program stored in the programmable read-only memory (PROM), a solid-state data-storage device whose contents is virtually indestructible. The main tasks of the 8-bit microprocessor are (a) control of the input multiplexer (b) start and control of the calibration cycle (c) correction of measured values according to the results of the calibration cycle (d) computation of periodic averages (e) calculation of output data (f) output of data and (g) control of peripherals. 

A second important architecture style for real-time signal processing systems is the multiplexed processor style, characterized by a set of application-specific, time-multiplexed data-paths steered by a hierarchically organized controller. This style is tuned to irregular applications, requiring a medium to high sample rate (10 kHz - 10 MHz). Many applications at these rates require a combination of computation-intensive arithmetic and complex decision-making operations. For these applications, the array style (as described in section 5) is unsuitable. 

A different multiplexing method was proposed by McLean and RusseUf utilizing rapid injection of ions into the drift tube at a frequency much faster than could be processed by a stand-alone IMS using one-dimensional time correlation creating a pseudo-continuous ion beam within the drift tube. In this instrumental arrangement, a TOFMS was utilized as a rapid and sensitive detector since both IMS and TOFMS achieve separation based on time dispersion of ions. Correlated multiplexed data acquisition allowed the use of ion injection rates much faster than that predicted to achieve 100% duty cycle in a sequential pulse-and-wait experiment, and improved usage of the bidimensional separation space. 

The timing required for digitizing and multiplexing data into a video stream depends on the specifics of the ADC system architecture. Figure 8.4 shows the timing required for the architecture in Figure 8.3 processing a 40M pixel/s sensor. 

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