GC-FID Chromatograms

These capillary GC-FID Chromatograms show the significant decrease in Impurity content from raw material to finished product 

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Figure 13.20 GC-FID chromatograms of an exuact obtained by (a) SPE and, (b) lASPE of 10 ml of municipal waste water, spiked with 1 p.g 1 of seven s-triazines (c) represents a blank mn from lASPE-GC-NPD of 10 ml of EIPLC water. Peak identification is as follows 1, ati azine 2, terbuthylazine 3, sebuthylazine 4, simetiyn 5, prometiyn 6, terbutiyn 7, dipropetiyn. Reprinted from Journal of Chromatography, A 830, J. Dalliige et al, On-line coupling of immunoaffinity-based solid-phase exUaction and gas chi-omatography for the determination of 5-triazines in aqueous samples , pp. 377-386, copyright 1999, with permission from Elsevier Science.

Fig. 14.13. Chromatograms showing single and comprehensive two-dimensional GC of drugs extracted from urine. (A) GC-FID chromatogram, (B) Pulsed GcxGC chromatogram (C) GCxGC contour plot. Adapted with permission from Ref. [15, Fig. 14.3]. Complete details on separation conditions and analyte identity can be found in the original paper.

Fig. 4 LC-GC-FID chromatograms for typical olive oils. The nearly complete absence of wax esters (esters 40-esters 46) and very low concentrations of steryl esters indicate a high-quality extra virgin oil. The concentration of free stigmasterol is low. C24-26-OH, fatty alcohols. In lampante oils, more wax esters and steryl esters are found. The concentration of stigmasterol increases more than campesterol if the oil was prepared from olives of low quality. Run at the same sensitivity, chromatograms of solvent-extracted oils are completely overloaded. The refined extraction oil was diluted 1 5 before running the chromatogram shown. Wax ester and steryl ester concentrations are very high. (From Ref. 34, p. 626.)...

Only preliminary quantitative evaluations for the derivatization/SFE of LAS have been performed, and it appears that the conditions described above yield only ca. 30 to 40% recovery of the native LAS with one derivatization/extraction step. It is apparent from the GC/FID chromatogram that the matrix contains a very high concentration of materials that react with the TMPA and it is likely that the reaction is reagent limited. This idea is further supported since three derivatization/SFE steps on one sample reduces the LAS to undetectable levels. 

FIGURE 5.4 GC-FID chromatogram of Cheddar cheese extract showing the amino acid profile. Norvaline was used as the internal standard (IS). 

Figure 13.16 LC separation of urban air particulate extract (a), along with the GC/FID chromatogram (b) of an oxy-PAC fraction (transferred via a loop-type interface). Reprinted from Environmental Science and Technology, 29, A. C. Lewis et al., On-line coupled LC-GC-ITD/MS for the identification of alkylated, oxygenated and nitrated polycychc aromatic compounds in urban air particulate extracts , pp. 1977-1981, copyright 1995, with permission from the American Chemical Society.

There is considerable variation in the sulfide content in these petroleums, ranging from 16% for Peace River, a bitumen, to 0.2% for Pembina, a conventional oil. The sulfide GC-FID chromatograms of some selected samples are shown in Figure 2, which shows considerable variation between the samples. For example, Bellshill Lake contains substantial quantities of monocyclic sulfides possessing a linear (n-alkane) carbon framework and these appear as partially-resolved clusters of peaks on the bottom chromatogram of Figure 2 (1935). 

Figure 2. GC-FID chromatograms for the sulfide fractions from different Alberta petroleums. The peaks labeled B13 and B20 correspond to the bicyclic terpenoid sulfides with 13 and 20 carbons, respectively. The peak labeled T23 corresponds to the tetracyclic terpenoid sulfide with 23 carbons and peaks due to the hopane sulfides are indicated at the end of the chromatograms. The clusters of peaks spaced one carbon apart on the Bellshill Lake trace correspond mainly to complex mixtures of isomeric monocyclic sulfides possessing a linear carbon framework. These sulfides have been removed by biodegradation from the upper two samples. For more complete peak identification see References 9, 10 and 35. (Reproduced from Reference 34. Copyright 1989, American Chemical Society.)...

The results of the analyses for the thiophenes for several petroleums are summarized in Table I. The thiophene contents vary from 0.3% to 7.6%. The GC-FID chromatograms for a few samples are displayed in Figure 3, where the peaks corresponding to dibenzothiophene and the isomeric monomethyldibenzothiophenes are indicated. Peak assignments are based on GC/MS determination of the molecular weight and the previously-assigned retention order of the isomeric monomethyldibenzothiophenes (26). The numbering system of dibenzothiophene is as follows ... 

Figure 3. GC-FID chromatograms for thiophene compound fractions from Alberta petroleums. The peak labels are as follows 1. dibenzothiophene, 2. 4-methyldibenzothiophene, 3. 2- and 3-methyldibenzothiophene and 4. 1-methyldibenzothiophene. Samples are arranged in order of their depth of burial. Note the shift toward lower molecular weight compounds and a reduction in the amount of the unresolved complex mixture with increasing depth of burial. (Reproduced from Reference 34. Copyright 1989, American Chemical Society.)...

Fig. 12.3 Fast cocaine determination in coca leaves by GC according to Ilias et al. (adapted from [37]). (a) Schematic of the total analysis time, (b) Fast GC-FID chromatogram using a short 100 p,m i.d. column and a fast oven temperature programming.

Constituents identRied in the intact ripe pineapple headspace sample are listed in Table V. Figure 3 shows a GC/FID chromatogram of pineapple headspace. The ester fraction comprises about 81% of the total area. QuantRatively, the major constituents were methyl... 

Figure 1 Typical GC-FID chromatograms of alkenone-containing sediment extracts.

Fig. 6.8. GC-FID chromatograms for the early-eluting peaks for PAH-contaminated soil extracted using the (A) Soxhiet, (B) ASE and (C) SFE techniques. IS internal standard, 1 naphthalene, 2 2-methylnaphthalene, 3 1-methylnaphthalene. (Reproduced with permission of Elsevier.)...

Petroleum hydrocarbon identification was based primarily on the GC-FID chromatogram patterns of the saturated and unsaturated... 

For comparison, GC-FID chromatograms of representative petroleum contaminants are shown in Figure 2 and chromatograms of hydrocarbons from various marine plants (biogenic) are given in Figure 3. Key pareimeters used for hydrocarbon characterization are listed in Table I. 

Figure 2. GC-FID chromatograms of reference petroleum products. Numbers indicate n-alkane carbon number represented by the adjacent chromatographic peak. I.S. indicates the position of the internal standeurd (5,a-androstane) chromatographic peak.

Generally, the type and identity of fresh to mildly weathered oils and petroleum products can be readily revealed from their GC-FlD traces, especially where the spilled oil or petroleum product is heavy and background hydrocarbon levels are low in an impacted environment. In addition to measuring TPH and other hydrocarbon groups in samples, GC-FID chromatograms provide a distribution pattern of petroleum hydrocarbons (e.g., carbon range and profile of UCM), fingerprints of the major oil components (e.g., individual resolved n-alkanes and major isoprenoids), and... 

FIGURE 27.2 GC-FID chromatograms of six oils. These six oils are different, as not only are there large differences in the n-allcane distrihutions and UCMs, hut also in relative ratios of isoprenoids to normal alkanes (see Table 27.6). Note that the Orinoco sample has nearly no n-alkanes on its GC-FID chromatogram. 

FIGURE 27.4 GC-FID chromatograms of six petroleum products (Jet fuel, Diesel, weathered Diesel, IFO-180, Fuel No. 5 (Bunker B), and Heavy Fuel Oil), illustrating differences of these products in the chromatographic profiles, carhon range, and UCM distrihution patterns. 

FIGURE 27.6 GC-FID chromatograms of six lubricating type oils demonstrating the considerable variability among this group of petroleum products. 

FIGURE 27.24 GC-FID chromatograms of Fraction 3 for -alkane and TPH analysis of three unknown oil samples. These three samples show very similar GC chromatographic profiles and distribution patters, featured by dominance of unresolved complex mixture (UCM) of hydrocarbons with very small amount of resolved peaks. 

Figure 1. GC/FID chromatogram of a standard solution in methylene chloride and acetone. 

Figure 4. SPME/GC/FID chromatogram of a water extract after the hot water extraction of rosemary at 100 °C. 

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