Chromatography GC/MS

Ring Currents Aromatic and Antiaromatic Magnetic Resonance Imaging Spectra by the Thousands Gas Chromatography GC/MS and MS/MS... 

Fish Extraction by column chromatography GPC fractionation solvent exchange fractionation of alkanes on silica gel column chromatography GC/MS Not specified Not specified Hesselberg and Seelye 1982... 

Artola-Garicano et al. [24] PCMs (AHTN and HHCB) - freely dissolved and total concentrations Influent, primary settler, aeration tank, secondary effluent, primary sludge, and waste sludge The Netherlands Freely dissolved - SPME with GC-MS - Limit of quantification=0.1 pg/L Total concentration - Liquid-liquid extraction with cyclohexane - Silica gel chromatography - GC-MS - Recovery=85-106% limit of quantification =0.1 pg/L... 

Rimkus et al. [23] NMs and monoamino metabolites Influent, effluent Germany - Liquid-liquid extraction with hexane - Silica gel and alumina chromatography - GC-MS/MS, GC-MS, GC-ECD, and GC-PND - Limits of quantification=l ng/L... 

Osemwengie et al. [14] NMs, PCMs, and nitromusk metabolites Wastewater effluent U.S. - On-site 60-L extraction with NEXUS sorbent - Silica gel and gel-permeation chromatography - GC-MS - Recovery=80-97% method detection limit =0.02-0.3 ng/L... 

Berset et al. [16] NMs and amino metabolites Sewage sludge Switzerland - Extraction with hexane by agitation - Gel-permeation chromatography and silica gel chromatography - GC-MS/MS, GC-MS (El, NCI, and PCI), H and 13C NMR - Recovery=51-116% detection limit=50 ng/L... 

Combined analytical techniques, such as ion chromatography, GC-MS and FTIR, were employed for the investigation of the photocatalytic decomposition of triazine-containing azo dyes in the presence of Ti02 suspensions. The chemical structures of the dyes are shown in Fig. 3.66. 

Table 5.3.2 The gas chromatography (GC)-MS urinary free cortisol (UFFj and metabolite panel internal standards, monitored ions, and normal excretions...

The successful combination of mass spectrometry with gas chromatography (GC-MS) and, subsequently, with liquid chromatography (HPLC-MS) allowed not only the determination of urea pesticides in food but also the identification of their residues at trace level. Mass spectrometry is a technique that can be used as a general detector, with cyclic scanning. The selectivity and sensibility of analysis can be enhanced using characteristic ions of the molecule, with selected ion monitoring (SIM). Urea pesticides have been determined by HPLC-MS directly (175-180), without the thermal instability problems of GC analysis. 

The detection, identification, and quantitative analysis of GSH conjugates have advanced with time as new analytical technologies and techniques become available (Baillie and Davis, 1993). GSH conjugates are chemically and thermally unstable, and they are very polar. Therefore, analysis using gas chromatography (GC)-MS requires... 

Note GC, gas chromatography GC/MS, gas chromatography/mass spectrometry GC-PID, gas chromatography-photoionization detector GC-ECD, gas chromatography-electron capture detector. 

If the species of interest happens to be volatile, it can be collected in the head space or atmosphere of a closed system, and subsequently determined by gas chromatography (GC), MS, or a combination of these (GC-MS). In some circumstances it is possible to convert non-volatile compounds into a volatile form by appropriate derivativisation (e.g. by alkylation, or formation of a metal chelate). Separation and analysis can then be based on GC. Species containing elements such as Sn, Pb, Hg, As, Sb, Bi, Se or Te can be separated from the matrix by conversion into a chemically stable and volatile hydride (e.g. by treatment in acid solution, with sodium borohydride, NaBH4). Mixtures of hydrides can be separated by GC and detected by an electron capture unit, or if only one element is of interest, the volatile hydride(s) can be fed to an element-specific detector such as an AAS unit (fitted with a heated quartz tube cell). 

The LC/MS analyses were performed with either thermospray ionization (TSI) or particle beam (PB) interfaces. These systems successfully analyzed the labile, polar, or higher mass compounds, whereas a complementary gas chromatography (GC)/MS system was used for volatile compounds. The LC/MS system proved to be widely applicable to a range of chemically diverse compounds. The TSI and PB systems were both successful for 80-90% of the compounds analyzed. Automated, open-access LC/MS analyses performed well because sample throughput was expected to reach 250,000 in 1995. This throughput corresponds to approximately 1000 samples per day. 

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