Peak area integrator method

Maximum power heating, the L vov platform, gas stop, the smallest possible temperature step between thermal pretreatment and atomisation, peak area integration, and matrix modification have been applied in order to eliminate or at least reduce interferences in graphite furnace AAS. With Zeeman effect background correction, much better correction is achieved, making method development and trace metal determinations in samples containing high salt concentrations much simpler or even possible at all. 

Figure 4.1 Illustration of the cut-and-weigh method for peak area integration.

Processing method Controls and documents integration parameters, component names, calibration and quantitation information Integration threshold, peak width, minimum peak area, integration events Component table component names, retention times, response factors... 

The SVOC testing provides the semivolatile emission value (TVOC) of the material analyzed. It is determined according to VDA 278 by the peak area integration of the sample chromatogram after thermal desorption at the higher temperature of 120 C. The result calculation is based and expressed as the area comparison with a 100 ng toluene analysis as standard. The calibration solution dissolved in methanol has been applied directly into Tenax filled desorption tubes and analyzed using the above described method for TD-GC-MS measurements. 

Apparatus. A gas chromatograph equipped with a flame-ionisation detector and data-handling system. The use of a digital integrator is particularly convenient for quantitative determinations, but other methods of measuring peak area may be used (Section 9.4). 

Chromatographic peak areas were measured by both manual and mechanical integration methods. Total analysis time was less than one hour per sample. 

Detection RI 16X, SP4050 Attenuation 10 Chart speed - Icm/min Analysis time - 24 min Total plate count - 2(10 ) plates Polydichlorophosphazene and cyclic trimer and tetran r standards were used for calibration. Standard methods were applied for integrating peak areas. 

Although the decomposition of a data table yields the elution profiles of the individual compounds, a calibration step is still required to transform peak areas into concentrations. Essentially we can follow two approaches. The first one is to start with a decomposition of the peak cluster by one of the techniques described before, followed by the integration of the peak of the analyte. By comparing the peak area with those obtained for a number of standards we obtain the amount. One should realize that the decomposition step is necessary because the interfering compound is unknown. The second approach is to directly calibrate the method by RAFA, RBL or GRAFA or to decompose the three-way table by Parafac. A serious problem with these methods is that the data sets measured for the sample and for the standard solution should be perfectly synchronized. 

In the DSC method, the sample and reference are maintained at the same temperature and the heat flow required to keep the equality in temperature is measured. Hence DSC plots are obtained as the differential rate of heating (in units of watts/second, calories/second, or Joules/second) against temperature. The area under a DSC peak is directly proportional to the heat absorbed or evolved by the thermal event, and integration of these peak areas yields the heat of reaction (in units of calories/second gram or Joules/second gram). 

The most popular method of measuring peak area is by integration. Integration is a method in which the series of digital values acquired by the data system as the peak is being traced are summed. The sum is thus a number generated and presented by the data system and is taken to be the peak area. See Figure 11.20. We will discuss in Chapters 12 and 13 exactly how this area is converted to the quantity of analyte in GC and HPLC and the issues involved. See Workplace Scene 11.7. 

Draw an example of an instrumental chromatography peak and show in your drawing and describe in words the specific method by which peak area is measured by integration. 

The relationship between the concentration of the solute and the peak produced in the chromatogram is, strictly speaking, only valid for peak area measurements, but in most instances it is more convenient to measure peak height. Such peak height measurements should only be used when all the peaks are very narrow or have similar widths. The tedium and lack of precision associated with non-automated methods of peak area measurements may be overcome using electronic integrators, which are features of most modern instruments. 

Gaussian curves are fitted to the data [28], and a peak area calculation program employed to integrate the area under each peak. This method is used to determine the evolution of peak area with time. The value of the extent of reaction, a, at a time t for any given Bragg reflection (hkl) is calculated using... 

Laeven and Smit presented a method for determining optimal peak integration intervals and optimal peak area determination on the basis of an extension of the mentioned theory. Rules of thumb were given, based on the rather complicated theory. Moreover, a simple peak-find procedure was developed, based on the derived rules. 

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