GC-EI-MS-analysis

Ropero-Miller JD, Lambing MK, Winecker RE. Simultaneous quantitation of opioids in blood by GC-EI-MS analysis following deproteination, detau-tomerization of keto analytes, solid-phase extraction, and trimethylsilyl derivatization. J Anal Toxicol 2002 26 524-8. 

Doco T, O Neill MA, and Pellerin P (2001) Determination of the neutral and acidic glycosyl-residue compositions of plant polysaccharides by GC-EI-MS analysis of the tri-methylsilyl methyl glycoside derivatives. Carbohydrate Polymers 46 249-259. 

Characteristic Fragment Ions Used for GC-EI-MS Analysis of Some Neutral Drugs, p-Blockers and P2 S)mipathomimetics... 

Analysis of underivatised APEOs by GC-EI-MS, has been used for the determination of the most volatile biodegradation metabolites in environmental samples. Thus, the presence of APEO (n < 4) in wastewater and sewage effluents [77,82-85], river water [27,86-93], drinking water [88,94,95], sediments [96] and air [97,98] has been widely reported. 

GC-EI-MS permits the direct analysis of mixtures, e.g., to analyze synthetic byproducts an advantage that made GC-EI-MS benchtop instruments become widespread in modem synthetic laboratories. The GC-EI-MS combination is especially successful in monitoring environmental pollutants such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-dioxins (PCDDs), polychlorinated dibenzofuranes (PCDFs), or other volatile organic compounds (VOCs). 

Vorce SP, Sklerov JH. 2004. A general screening and confirmation approach to the analysis of designer tryptamines and phenylethylamines in blood and urine using GC-EI-MS and HPLC-electrospray-MS. J Anal Toxicol 28 407. 

GC/MS(/MS) is also popular for quantifying DBFs. Selected ion monitoring (SIM) or multiple reaction monitoring (MRM) mode are used with GC/MS and GC/ MS/MS, respectively, to maximize the sensitivity and provide low detection limits. Some EFA Methods utilize GC/MS, including EFA Method 524.2, which uses GC/ EI-MS for THM analysis [155], and EFA Method 521, which uses for GC/CI-MS/ MS for nitrosamine analysis [55]. In addition, many priority unregulated DBFs have been measured using GC/MS in a U.S. Nationwide Occurrence Study [11,12]. 

Lacorte, S., I. Guiffard, D. Fraisse, et al. 2000. Broad spectrum analysis of 109 priority compounds listed in the 76/464/CEE Council Directive using solid-phase extraction and GC/EI/MS. Anal. Chem. 72 1430-1440. 

Compounds with a sufficient volatility and thermal stability can be ionized in the vapor phase by bombardment with high-energy electrons which removes electrons from occupied orbitals [107]. According to our search of the literature, the first mass spectrometric analysis of toxaphene was reported in 1966 [108], and the first GC/EI-MS of a single toxaphene was published in 1974 [62]. Nowadays, numerous references are available containing many mass spectra and detailed descriptions of the EI-MS-fragmentations of polychlorinated bornanes [109-116]. Here, only the basic approach is given for the interpretation of El-MS. Most El-MS of polychlorinated bornanes lack the molecular ion in contrast to toxaphene components with one or two double bonds where it is clearly visible [109]. 

Unlike the case for other chlorinated compounds such as PCBs, double charged ions (at m/z values < MG/2 and with only 1 u between the chlorine isotope peaks) have not been mentioned for toxaphene components. The analysis of the GC/EI-MS fragmentation patterns allows a partial structure elucidation and the confirmation of the presence of a bornane skeleton. This knowledge facilitates a further structure elucidation by H-NMR spectroscopy [111]. 

It also accommodates a flash GC interface for more detailed analyses using the optional El source. The combination of PI and El in a single instrument offers the flexibility to conduct rapid screens of mixtures by PI and subsequently confirm the analysis by GC-EI MS. It is capable of direct analysis of air, liquid and soil samples. 

Guillamon, M., Martinez, E., Eljarrat, E., and Lacorte, S., Development of an analytical procedure based in accelerated solvent extraction and GC-EI-MS for the analysis of 40 PBDEs in human milk, Organohalogen Compel., 55, 199-202, 2002. 

Several methods for qualitative and quantitative analysis have been developed involving GC-NCT MS and GC-EI-MS. Until recently, quantitative work has been performed by using technical PBDE products, i.e., Bromkal 70-5DE (BK70), due to the lack of pure reference standards for most PBDE congeners. The major three components in BK70... 

Oxysterols in plasma are usually analyzed by GC-MS. Dzeletovic et al. developed a classical methodology which is still widely adopted today [63]. Oxysterols are found in plasma mostly esterified with fatty acids but also with sulfuric acid and as an acetal with glucuronic acid [64,65]. The protocol developed by Dzeletocvic et al. focused on fatty acids esters, so an initial base hydrolysis step was performed with KOH in ethanol. Following neutralization with phosphoric acid and a Folch-like extraction into CHCI3, oxysterols were separated from other less polar sterols on a silica cartridge. Derivatization was performed with pyridine hexameth-yldisilazane trimethylchlorosilane 3 2 1 (v/v/v) and analysis of the TMS ethers by GC-EI-MS. Nine oxysterols were identified in plasma using this protocol includ-... 

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