Peak height evaluation

The molybdenum concentration in the reference sample is rather high and a direct determination using the cookbook conditions [710] is very straightforward. There is no difference between peak area and peak height evaluation. In spite of 1800 °C for thermal pretreatment, a small background absorption signal is present. 

Perkin-Elmer M 2100 atomic absorption spectrometer with deuterium lamp background corrector. Cadmium and lead hollow cathode lamps operated at 4 mA and 7 mA, and 228.8 nm and 283.3 nm wavelength respectively. Spray chamber used without impact system. Acetylene flow-rate 1.0 1 min , air flow-rate 10 1 min (extra-lean flame). Peak height evaluation with a time constant of 0.5 s. FI peaks recorded by a printer or chrrt recorder. 

The use of peak area integration instead of the peak height evaluation may eliminate kinetic interferences. 

Internal standard method Peak height evaluation... 

Peak height evaluation Peak ratio evaluation... 

The external reflection of infrared radiation can be used to characterize the thickness and orientation of adsorbates on metal surfaces. Buontempo and Rice [153-155] have recently extended this technique to molecules at dielectric surfaces, including Langmuir monolayers at the air-water interface. Analysis of the dichroic ratio, the ratio of reflectivity parallel to the plane of incidence (p-polarization) to that perpendicular to it (.r-polarization) allows evaluation of the molecular orientation in terms of a tilt angle and rotation around the backbone [153]. An example of the p-polarized reflection spectrum for stearyl alcohol is shown in Fig. IV-13. Unfortunately, quantitative analysis of the experimental measurements of the antisymmetric CH2 stretch for heneicosanol [153,155] stearly alcohol [154] and tetracosanoic [156] monolayers is made difflcult by the scatter in the IR peak heights. 

The correction due to the temperature gradient in the capillary wave peak heights is the corresponding fractional difference, which can be obtained by evaluating A(<7, = w. The result is simple ... 

Our calculations show that the systematic errors for the evaluation of the triangle height are lower then for the peak height and peak ar ea. It is to be noted that tangent method allows estimating of the latent peak in the overlapped signals when peak area and peak maximum determination is impossible. 

In our early evaluations, three parameters were utilized for the resolving power of the columns (3,4,7). These were the valley-to-peak height ratio, v, the peak separation parameter, P, and the parameter mentioned earlier, Djcr. The valley-to-peak height ratio is defined as... 

In their work on the precision of contemporary liquid chromatographic measurements, Scott and Reese (3) also evaluated the precision that could be expected from a computer measuring peak heights and peak areas. They again used twelve replicate samples and the results they obtained are shown in table 2. 

The factors chosen for study were the concentration of the ion-pairing reagent, the solution pH ( quantitative factors) and the acid chosen for pH adjustment (formic, acetic, propionic and trifluoroacetic acids) ( quahtative factor). The effect of these factors was assessed by using responses that evaluated both the HPLC (the number of theoretical plates and the retention time) and MS performance (the total peak area and peak height) for each of the four analytes studied, i.e. 1-naphthyl phosphate (1), 1-naphthalenesulfonic acid (2), 2-naphthalenesulfonic acid (3) and (l-naphthoxy)acetic acid (4). 

Results The raw data consisted of peak height ratios of signal internal standard, see data files VALIDl.dat (primary validation m - 0 repeats at every concentration), VALID2.dat (between-day variability), and VALID3. dat (combination of a single-day calibration with several repeats at 35 and 350 [ng/mlj in preparation of placing QC-sample concentration near these values). Fig. 4.29 shows the results of the back-calculation for all three files, for both the lin/lin and the log/log evaluations. Fig. 4.30 shows the pooled data from file VALID2.dat. 

The highest separation standards are set for preparative separations beeanse the resolution has to be at least 1.5 (6 o), ensuring that peaks are separated eompletely (Figure 5.1). It is based on the faet that the whole substance peak is intended to be recovered to the highest degree of purity. In contrast, for quantitative purposes a resolution of 1.0 (4 a) is sufficient, because then a peak is pure at its maximum and can be evaluated by peak height. 

Molybdenum is an element for which platform atomisation does not offer an advantage. Just the opposite is the case sensitivity is very poor and memory effects are very strong. The Zeeman detection limit for wall atomisation in a pyrocoated graphite tube using 100 til of reference solution is 0.03 xl (for both peak height and peak area evaluation) [709]. 

The traditional method of determining the position of an analyte spot on the plates is a visual evaluation. However, this technique is highly subjective and depends considerably on the expertise of the analytical chemist. TLC scanners, developed for exact determination not only pinpoint position but also the area, intensity and symmetry of the spot, overcome the uncertainty of the visual evaluation. Moreover, TLC scanners make possible more accurate determination of the quantity of analyte in the spot by converting spot characteristics into peak characteristics. Peak height is the distance between the peak maximum and the baseline, whereas peak area is the area of the peak between the beginning and end of the peak and the baseline. 

Have you had an opportunity to evaluate the results from peak heights versus peak area measurements ... 

HPLC has more or less supplanted GC as a method for quantifying drugs in pharmaceutical preparations. Many of the literature references to quantitative GC assays are thus old and the precision which is reported in these papers is difficult to evaluate based on the measurement of peak heights or manual integration. It is more difficult to achieve good precision in GC analysis than in HPLC analysis and the main sources of imprecision are the mode of sample introduction, which is best controlled by an autosampler, and the small volume of sample injected. However, it is possible to achieve levels of precision similar to those achieved using HPLC methods. For certain compounds that lack chromophores, which are required for detection in commonly used HPLC methods, quantitative GC may be the method of choice, for analysis of many amino acids, fatty acids, and sugars. There are a number... 

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