Computer data system

More likely now, the analog electrical signal will be digitized and processed by a computer (data) system. Alternatively, a time-to-digital converter can be used as an ion collector (see Chapter 31). 

The amplified signal can be recorded directly by analog means but, more likely, the signal is digitized and processed by a computer (data system). 

The most recent extension of instrument automation has come with the availability of practical laboratory robotics systems. These systems can be as easy to implement as the personal computer data system and extend automation beyond control, data collection and... 

The mass spectrometer, when combined with a computer data system, precisely identifies and quantifies each sample component as it elutes from the gas chromatography. The model 1020 uses an electron ionization source... 

The technique requires simultaneous fast and accurate measurements of both the vertical velocity and the trace species in question. Fortunately the technology for the measurement of turbulence with the necessary resolution is available. Sonic anemometers can readily yield air motion data with the required resolution (10). Likewise, the ability to handle the air motion and chemical concentration data with modern computer data systems is well in hand (II). Thus these aspects can be ignored, and the major limitation can be dealt with the availability of appropriate chemical sensors with sufficient time and chemical resolution. 

Data recorder computer data system or integrator... 

Most HPLC instruments include computer data systems which automatically plot peak response versus concentration to generate response factors however, if using an older system, the standard curve can be plotted manually. The calibration curves should be linear with a correlation coefficient of >0.98 and intersect very near the origin. 

Some computer data systems have based their resolution calculations on the peak width at half the distance from the apex to the base of the peak [49]. Peak widths have also been measured at the point of inflection. 

Figure 1.11. The effect of sample size and isotope abundance on the accuracy of isotope ratio measurements in GC-MS using a quadrupole instrument and computer data system. The curves are based on numerous separate studies (reproduced from reference [110])...

System suitability is guaranteed if both apparatus test and validation match their requirements. It is best performed on a routine basis and can be done very easily if the HPLC apparatus is equipped with a computer data system. Then during each run or in well-defined intervals a number of parameters are acquired plate number, resolution, precision, retention time, relative retention time (i.e. k value) and peak asymmetry-also if necessary linearity and limits of quantification. The results are followed by statistical tools, including easy-to-monitor graphical documentation with control charts. ... 

Integrator Test (not applicable for computer data systems)... 

The Luggin probe used to monitor the potential of the Hg indicator electrode is spaced close ( 1 mm) to the mercury droplet to reduce ohmic resistance. The top barrel is cleaned, wetted with concentrated NaNOj solution, and closed. Sufficient conductivity exists in this solution layer to permit the small currents necessary for potentiometric determination. When an excess of mercurous ion is generated, the potential of the Hg/Hg couple varies in accordance with the Nemst equation, and a voltage follower may be used to output the voltage curve to a computer data system. For precise work, dissolved oxygen should be removed from the supporting electrolyte and efficient stirring is needed. 

Figure 15.38 Schematic of the eluent suppression approach for IC that permits conductometric detection of analytes. The Y-time plotter is a computer data system on modern systems.

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