GC-MS analytical procedure

A. Andreotti, I. Bonaduce, M.P. Colombini, G. Gautier, F. Modugno, E. Ribechini, Combined GC/MS analytical procedure for the characterization of glycerolipid, waxy, resinous, and proteinaceous materials in a unique paint microsample, Analytical Chemistry, 78, 4490 4500 (2006). 

This chapter gives an overview of GC/MS analytical procedures used for lipid determination, and a summary of the complex issue of lipid chromatographic data interpretation in paintings and archaeological objects. Some examples and case studies are also included. 

The higher detection limits for sulfur mustard in the EDS tests at Porton Down reflect the GC/MS analytical procedure used by the Defence Evalnatiai and Research Agency in the United Kingdom, which, along with contracted commercial laboratories, performed the neutralent analyses. 

In view of the importance of the Dorstenia based crude drug preparation, carapia in Brazil, capillary gas chromatographic procedures for the quantification of furocoumarins and other constituents from rhizomes and aerial parts of D. tubinica, D. asaroides and D.vitifolia, and a high resolution gc/ms analytical method for the non polar constituents of... 

Two independent research groups at our hospital have pursued the development of analytical methodology for THC and its metabolites in urine. One group, under L. E. Hollister, has directed its efforts primarily toward fractioning the in vivo THC metabolites by solvent partitioning and by TLC. The other group, under I. S. Forrest and D. E. Green, has been concerned with the development of an automated GC/MS quantitative procedure. ... 

Whilst for the analysis of plant material for cannabinoids both GC and HPLC are commonly used, in analytical procedures the employment of GC-based methods prevails for human forensic samples. Nonetheless, the usage of HPLC becomes more and more of interest in this field especially in combination with MS [115-120]. Besides the usage of deuterated samples as internal standards Fisher et al. [121] describe the use of a dibrominated THC-COOH (see 7.5). The usage of Thermospray-MS and electrochemical detection provide good performance and can replace the still-used conventional UV detector. Another advantage in the employment of HPLC rather than GC could be the integration of SPE cartridges, which are needed for sample preparation in the HPLC-system. 

The method using GC/MS with selected ion monitoring (SIM) in the electron ionization (El) mode can determine concentrations of alachlor, acetochlor, and metolachlor and other major corn herbicides in raw and finished surface water and groundwater samples. This GC/MS method eliminates interferences and provides similar sensitivity and superior specificity compared with conventional methods such as GC/ECD or GC/NPD, eliminating the need for a confirmatory method by collection of data on numerous ions simultaneously. If there are interferences with the quantitation ion, a confirmation ion is substituted for quantitation purposes. Deuterated analogs of each analyte may be used as internal standards, which compensate for matrix effects and allow for the correction of losses that occur during the analytical procedure. A known amount of the deuterium-labeled compound, which is an ideal internal standard because its chemical and physical properties are essentially identical with those of the unlabeled compound, is carried through the analytical procedure. SPE is required to concentrate the water samples before analysis to determine concentrations reliably at or below 0.05 qg (ppb) and to recover/extract the various analytes from the water samples into a suitable solvent for GC analysis. 

The analytical method to determine carfentrazone-ethyl and the major animal metabolites (C-Cl-PAc and C-Pac) in bovine matrices is similar to the method for crop matrices. The hexane-aqueous partition to separate carfentrazone-ethyl from the acid metabolites can be replaced by a Cig SPE cartridge. After the SPE, use 12 mL of water-acetonitrile (7 3, v/v) to elute the metabolites and then use 12 mL of hexane-ethyl acetate (4 1, v/v) to elute carfentrazone-ethyl after drying the cartridge. Follow the rest of the respective analytical procedures for carfentrazone-ethyl and the acid metabolites described in Sections 6.3 and 6.4. However, no reflux under boiling is necessary for the analysis of acid metabolites based on a goat metabolism study, because no conjugated acid metabolites were detected. Also, since HM-C-Cl-Pac is not analyzed for in the bovine matrices, no acylation is needed in the method. Analyze the metabolites by GC/MS, and monitor the ions at m/z 362 for C-Cl-Pac and 303 for C-PAc. 

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