GC—flame ionization detection

Kirkbride (1987) described the estimation of diazinon in human omental tissue (fatty tissue) after a fatal poisoning. In this method, the tissue was pulverized and extracted with acetone. After extract concentration and purification by sweep co-distillation and Florisil fractionation, diazinon was measured by gas chromatography (GC) with nitrogen-phosphorus detection (NPD). After another fatal diazinon poisoning, diazinon was quantified by GC/electron capture detection (ECD) and GC/flame ionization detection (FID) by Poklis et al. (1980). The diazinon in human adipose, bile, blood, brain, stomach contents, kidney, and liver was recovered by macerating the sample with acetonitrile followed by the addition of aqueous sodium sulfate and extraction into hexane. Following an adsorption chromatography clean-up, the sample was analyzed. 

Sample Concentration Experiments. A CLLE quality assurance blank was run by extracting 90 L of Milli-Q water with three CLLE samplers in a parallel configuration and concentrating the composited extract to 4 mL by Kudema-Danish evaporation. The 22,500-fold concentrate was analyzed by GC-flame ionization detection (GC-FID) and GC-MS. Thirty-two peaks were observed by using GC-FID analysis, but because of their low concentrations, only four contaminants were identified by GC-MS cyclohexene, 2-cyclohexen-1-one, n-butyl phthalate, and bis(2-ethylhexyl) phthalate. Cyclohexene is a solvent preservative that has been identified in commercial high-purity methylene chloride (16), and 2-cyclohexen-l-one is its air oxidation product. The phthalates are ubiquitous laboratory contaminants and have also been identified in commercial methylene chloride (17). 

Galacturonic acid, characterized, 739 Gas chromatography (GC) flame ionization detection (FID) characteristics of, 449 cholesterol, 461... 

The impact of several factors on the MMLLE extraction yield of PAHs in water has been comprehensively studied using a flowing FS-MMLLE system and off-line analysis with GC-flame ionization detection (GC-FID).84 The flowing FS-MMLLE procedure combined with off-line GC-mass spectrometry (GC-MS) analysis has been utilized for the extraction of nonionic and derivatized ionic organotin compounds in river water.85... 

Screening methods are available for analysis of benzene in feces and urine (Ghoos et al. 1994) and body fluids (Schuberth 1994). Both employ analysis by capillary GC with an ion trap detector (ITD). Benzene in urine has been determined by trapping benzene stripped from the urine on a Carbotrap tube, followed by thermal desorption GC/flame ionization detection (FID). The detection limit is 50 ng/L and the average recovery is approximately 82% (Ghittori et al. 1993). Benzene in urine has also been determined using headspace analysis with capillary GC/photoionization detection (PID). The detection limit is 40 ng/L (Kok and Ong 1994). 

Although not the preferred method, GC may still be used to measure MBOCA and its metabolites in urine. Analysis of a heptafluorobutyryl derivative of MBOCA using GC/ECD has been frequently used (Gristwood et al. 1984 NIOSH 1984 Thomas and Wilson 1984), but GC/flame ionization detection (FID) has also been used to analyze a trifluoroacetyl derivative (Van Roosmalen et al. 

Although, direct injection with GC-flame ionization detection (FID) is sensitive enough to quantify methanol and fusel oils, it is advisable only for spirits because of the dirt accumulated in the injection port when beer, wine, or liqueurs are analyzed. Thus, liquid-liquid extraction has been widely applied to separate and concentrate fusel oil from beer, wine, and distilled alcoholic beverages, followed by GC determination of the compounds. Nowadays, many simpler and online extraction techniques are applied... 

Fig. 1 GC-flame ionization detection chromatogram of a complex mixture of PAHs extracted by SFE from a contaminated soil. (1) naphthalene, (2) 2-methylnaphthalene, (3) 1-methylnaphthalene, (4) acenaphthene, (5) fluorene, (6) dibenzothiophene, (7) phenan-threne, (8) anthracene, (9) fluoranthene, (10) pyrene, (11) benzo(a)anthracene, (12) chrysene, (13) henzo(e)pyrene, (14) benzo(a)pyr-ene, (15) indeno(l,2,3-cd)pyrene, (16) dibenzo(a,h)anthracene, (17) benzo(g,h,i)per-ylene.

Fig. 2 GC-flame ionization detection chromatograms containing early artifact peaks from different solvent extraction methods Soxhlet, ASE (PLE), SFE, and suhcritical water extraction of a soil sample collected from a manufacturing gas plant site. The numbers refer to PAHs identified in the legend of Fig. 1.

Ylinen et al. [62] developed an ion-pain extraction procedure employing tetrabutyl ammonium (TEA) counter ions for the determination of PFOA in plasma and urine in combination with gas chromatography (GC) flame ionization detection (FID). Later, Hansen et al. [53] improved the sensitivity of the ion-pair extraction approach using methyl tertiary butyl ether (MTBE) and by inclusion of a filtration step to remove solids from the extract, making it amenable for liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) determination. Ion pan-extraction procedure has been the basis of several procedures for biota [63-65] and food samples [66, 67]. However, this method has shown to have some limitations, such as (1) co-extraction of lipids and other matrix constituents and the absence of a cleanup step to overcome the effects of matrix compounds and (2) a wide variety of recoveries are observed, typically ranging from <50% to >200%. 

Figure 3 Gas chromatography-mass spectrometric reconstructed ion chromatogram (RIC) of a typical crude oil. A RIC is equivalent to a GC flame ionization detection trace. The presence of triterpanes and steranes eluting between /j-C and n-C i are not evident due to low abundance and interference of coeluting compounds. Conditions Finnigan (San Jose, CA), 9610 gas chromatograph, Supelco (Bellefonte, PA), 30 m X 0.25 mm ID (0.1- Xm film thickness) DB-1 fused silica capillary column, temperature programmed from 120 to 310°C at 8°C/min, 1-pl injection at 50 1 split. Mass spectrometer Finnigan TSQ-46B, 70-eV electron ionization, full-scan mode from 35 to 500 Da in 1 sec cycle time.

---