Chromatogram for

Petroleum Industry Gas chromatography is ideally suited for the analysis of petroleum products, including gasoline, diesel fuel, and oil. A typical chromatogram for the analysis of unleaded gasoline is shown in Figure 12.25d. 

Although aimed at the introductory class, this simple experiment provides a nice demonstration of the use of GG for a qualitative analysis. Students obtain chromatograms for several possible accelerants using headspace sampling and then analyze the headspace over a sealed sample of charred wood to determine the accelerant used in burning the wood. Separations are carried out using a wide-bore capillary column with a stationary phase of methyl 50% phenyl silicone and a flame ionization detector. 

Fig. 14. Molecular weight characteristics of novolac resins. Shown is the size-exclusion chromatogram for a typical commercial novolac polymer. The unsymmetrical peak shape reflects the multimodal molecular weight distribution of the polymer.

Figure 18. Vacancy Chromatograms for the Separation of a Four Component Mixture...

The fluorescence intensity was stabilized and enhanced (ca. 2-fold) by immersion of the chromatogram for 1 s in a mixture of liquid paraffin — -hexane (1 + 2). 

Note Note that the diazotization of primary aromatic amines can also be achieved by placing the chromatogram for 3 — 5 min in a twin-trough chamber containing nitrous fumes (fume cupboard ). The fumes are produced in the empty trough of the chamber by addition of 25% hydrochloric acid to a 20% sodium nitrite solution [2, 4], iV-(l-Naphthyl)ethylenediamine can be replaced in the reagent by a- or -naphthol [10, 14], but this reduces the sensitivity of detection [2]. Spray solutions Ila and lib can also be used as dipping solutions. 

Additional dipping in a 0.001% solution of dansyl semipiperazide or bis-dansyl piperazide in dichloromethane — liquid paraffin (75 -F 25) stabilized the color of the chromatogram for a period of months. 

Immerse the dried chromatogram for 1 s in the reagent solution and then heat to 40 - 50 °C in the drying cupboard for 10 min. 

Figure 16.15 shows the resulting chromatograms for the three glucan fractions obtained by previous preparative separation on Sephacryl S-200/S-1000 (Fig. 16.14). From the normalized fraction chromatograms, the elution profile of the initial mixture has been reconstructed by mixing 50% fraction 1, 40% fraction 2, and 10% fraction 3. Compared to the chromatogram of the preparative Sephacryl S-200/S-1000 system, separation with the TSK/ Superose system yields improved resolution in the low dp (high V, ) domain.

Comparison of the separation efficiency between two columns in the same mobile phase or one column in two mobile phases is based on the extent of resolution of the peaks of the PEO standards in the respective chromatograms of the PEO A, B, and C group. Due to the limitation of space, only the TSK PEO A chromatograms for the four columns in water and water/methanol are... 

Each of the four columns was packed with CPG00120C d = 13.0 nm). The column dimensions and experimental conditions are listed in Table 23.1. The flow rates (solution and solvent) were set to be proportional to the cross section of the column, whenever possible. The number of drops collected in each test tube was almost proportional to the cross section, especially for the initial fractions that might show a shift in M. Figure 23.9 shows chromatograms for some the fractions separated using 2.1-, 3.9-, and 7.8-mm i.d. columns. The result with the 7.8-mm i.d. column is a reproduction of Fig. 23.2 (3). Chromatograms of the fractions obtained from the 1.0-mm i.d. column overlapped with the chromatogram of the injected polymer sample (not shown). 

FIGURE 3-27 Three-dimensional chromatogram for oxidizable biological compounds at a multichannel amperometric detection system, consisting of an array of 16 carbon-paste electrodes held at different potentials. AA = ascorbic acid NE = norepinephrine DOPAC = 3,4-dihydroxyphenylacetic acid 5-HIAA = 5-hydroxyindole-3-acetic acid DA = dopamine HVA = homovanillic acid. (Reproduced with permission from reference 68.)... 

A GC trace of Octa, under conditions similar to those described by Timmons and Brown (ref. 4), closely resembled the published chromatogram for trace impurities in Deca. Material isolated from HPLC peak 7 (Figure IB) eluted from the GC (Figure 2) in a position corresponding to one of the octabromo isomers in the published work. This agrees with the assignment of peak 7 as an octabromo isomer in this work. Material isolated from HPLC peaks 8 and 9 (Figure IB and... 

Figure 3.20 Reconstructed ion chromatograms for the ions observed in the background-subtracted mass spectrum obtained from the component eluting after 5.05 min in the LC-MS analysis of a pesticide mixture. From applications literature published by Micromass UK Ltd, Manchester, UK, and reproduced with permission.

Figure 5.58 Reconstructed LC-MS-MS ion chromatograms for selected-reaction monitoring of methoxyfenozide using the m/z 367 to m/z 149 transition from the continual post-column infusion of a standard solution of analyte during the HPLC analysis of a...

Figure 5.67 Reconstructed ion chromatograms for Idoxifene and internal standard (ds-Idoxifene using LC-ToF-MS for (a) double-blank human plasma extract, (b) extract of blank human plasma containing internal standard (IS), and (c) control-blank human plasma spiked with Idoxifene at 5 gml , the LOQ of the method. Reprinted from 7. Chromatogr., B, 757, Comparison between liquid chromatography-time-of-flight mass spectrometry and selected-reaction monitoring liquid chromatography-mass spectrometry for quantitative determination of Idoxifene in human plasma , Zhang, H. and Henion, J., 151-159, Copyright (2001), with permission from Elsevier Science.

Automatic data processing has been implemented by assigning each specimen to a class. The chromatogram for that specimen can be processed automatically in the same way that the chromatogram of a standard member of the class was previously processed Interactively by the operator. 

To characterize the difference between two chromatograms, an overall mismatch index and a list of the areas, helglits, and positions of the main peaks in the difference chromatogram are provided. The difference chromatogram is the result of subtracting the standard chromatogram for that class of specimen from the chromatogram of the specimen. 

Figure 5. Chromatograms for theophylline in plasma extracts. Arrow indicates tneophyUine peak. Conditions 50 cm X 3 mm (i.d.) column with 10 fjm silica gel (Micropak Si 10 Varian) mobile phase, 84/15/1 chloroform/isopropanol/acetic acid flow rate, 40 rm/hr detector, UV,273nm(40).

In order to cadculate a particle size distribution directly from the output chromatogram for a polydisperse system, the integral, dispersion equation for the chromatogram signal, F(V), as a function of elution volume, V, needs to be evaluated (27) ... 

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