Gas Chromatography with Mass Spectrometric Detection

the use of chromatographic methods does not exclude the principle of confirming a positive result by using a completely different method, as no method is completely error-free. 

The use of GC/MS for the determination of medicaments and drugs of abuse must be regarded as the gold standard , as no other method enables so many substances to be determined with certainty and sensitivity [36]. As early as 1985, the GC/MS system had been put forward by the Deutsche Forschungsgemeinschaft as the most informative method used in the determination of addictive substances [27]. However, as the costs of this method of analysis were very high at that time, its use was reserved for special investigations. Even now, GC/MS is often only used in the field of forensic 

The basic equipment of the analyst who is interested in drug screening from urine by GC/MS must include comprehensive data collections. To answer questions about mass spectra of drugs of abuse or their metabolites, derivatized or underivatized, and their retention indices, a number of libraries of spectra are commercially available. These can now be obtained from many equipment manufacturers and are linked to the equipment software as a standard facility. Information on the analytical methods to be used and their limits of detection or the metabolism and pharmacology of the relevant substances can be obtained from the reference books or information sheets provided by the pharmaceutical manufacturers. 

In this connection, it is well known that the limits of determination of individual substances for these special investigations can be improved by optimizing a method to suit a particular problem, e.g., by the choice of certain molecular fragments (SIM). However, bearing in mind the complexity of the relevant substances, more attention should be paid to the question of how many substances or accompanying medicaments, after consumption in concentrations associated with therapy or abuse, can be determined with sufficient sensitivity in the urine using a GC/MS method of general application. The limits of detection of important substances are discussed in Section 8.2.1.5. It should also be pointed out that in GC/MS analysis the quality of the analytical results is extremely dependent on the capabilities of the people who evaluate them. 

2 High Performance Liquid Chromatography with Diode Array Detection (HPLC/DAD) 

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Sinex et al. [71] have described a method for the determination of methyltin compounds based on reaction with sodium borohydride to form tin hydrides then purge and trap analysis followed by gas chromatography with mass spectrometric detection. Down to 3-5pg absolute (as tin) of methyltin compounds equivalent to the sub pg kg 1 range can be determined by this procedure. 

Ziihlke S, Diinnbier U, Heberer T (2004) Detection and identification of phenazone-type drugs and their microbial metabolites in ground and drinking water applying solid-phase extraction and gas chromatography with mass spectrometric detection. J Chromatogr A 1050 201-209... 

G. S. Frysinger and R. B. Gaines, Comprehensive two-dimensional gas chromatography with mass spectrometric detection (GC X GC/MS) applied to the analysis of petroleum , J. High Resolut. Chromatogr. 22 251-255 (1999). 

Figure 13.19 Chromatograms obtained by on-line SPE-GC-MS(SIM) of (a) 10 ml of tap water spiked with pesticides at levels of 0.1 ng 1 1 (b) 10 ml of a sample of unspiked tap water. Peak identification for (a) is as follows 1, molinate 2, a-HCH 3, dimethoate 4, simazine 5, atrazine 6, y-HCH 7, 8-HCH 8, heptachlor 9, ametryn 10. prometryn 11, fen-itrothion 12, aldrin 13, malathion 14, endo-heptachlor 15, a-endosulfan 16, tetrachlor-vinphos 17, dieldrin. Reprinted from Journal of Chromatography, A 818, E. Pocurull et al., On-line coupling of solid-phase extraction to gas chromatography with mass spectrometric detection to determine pesticides in water , pp. 85-93, copyright 1998, with permission from Elsevier Science.

E. Pocurull, C. Aguilar, F. Borrull and R. M. Marce, On-line coupling of solid-phase extraction to gas chromatography with mass spectrometric detection to determine pesticides in water , J. Chromatogr. 818 85-93 (1998). 

HPLC with fluorescence detection gave results for polycyclic aromatic hydrocarbons which were comparable to those obtained by gas chromatography with mass spectrometric detection. 

B.A. Tomkins and G.A. Sega, Determination of thiodiglycol in groundwater using solid-phase extraction followed by gas chromatography with mass spectrometric detection in the selected-ion mode, J. Chromatogr. A, 911, 85-96 (2001). 

The focus of most archaeological ceramic studies has been on provenance or technology. There is also a growing body of specific evidence on how the pottery was used. Chapter 21 by Beck, Smart, and Ossenkop describe the organic tars used to line ancient Mediterranean amphoras. Chapter 21 includes a description of how the residues from amphora contents can be analyzed. As in most cases where unknown organic materials are encountered, the most powerful analytical technique is gas chromatography with mass spectrometric detection (GC-MS). This technique is expensive for the analysis of large numbers of samples. 

Lopez, R., Aznar, M., Cacho, J., Ferreira, V. (2002). Determination of minor and trace volatile compounds in wine by solid-phase extraction and gas chromatography with mass spectrometric detection. J. Chromatogr. A, 966, 167-177. 

One of the early methods for mass spectrometric analysis of microdialysis samples utilized gas chromatography with mass spectrometric detection (GC/MS). Electron ionization is one type of ionization used for GC/MS. It is a hard ionization technique, resulting in a high degree of analyte fragmentation. A softer form of ionization, chemical ionization, is also available and often results in less analyte fragmentation. Selected-ion monitoring (SIM) is used frequently with... 

Musshoff F, Junker H, Madea B. Simple determination of 22 organophosphorus pesticides in human blood using headspace solid-phase microextraction and gas chromatography with mass spectrometric detection. J Chromatogr Sci 2002 40 29-34. 

The PCDD and PCDF were determined by high-resolution capillary gas chromatography with mass spectrometric detection. Each isomer was identified and confirmed, using at least two columns with different stationary phases and polarity, by comparing the relative retention times of the peaks in the calibration and sample chromatograms. The final quantification was made using relative peak height or peak area. The GC and MS conditions used by each laboratory are summarised elsewhere [18,19]. 

Another development, also with a history in chemistry, is second-order calibration, where rank annihilation was developed for analyzing data from typically hyphenated instruments. This includes excitation-emission fluorescence spectra of different samples, liquid chromatography with ultraviolet (UV) detection for different samples and gas chromatography with mass spectrometric detection for different samples, giving an array. An illustration is given in Figure 10.2. 

PL 95-3327 SMT4-CT96-2142 Determination of priority herbicides and insecticides by gas chromatography with mass spectrometric detection after solid-liquid extraction. 

Aguilar, C., Penalver, S., Pocurull, E., Borrull, F., and Marce, R. M., Solid-phase microextraction and gas chromatography with mass spectrometric detection for the determination of pesticides in aqueous samples, J. Chromatogr. A, 795, 105-115, 1998. 

Berset, J. D. and Etter-Holzer, R., Determination of phthalates in crude extracts of sewage sludges by high-resolution capillary gas chromatography with mass spectrometric detection, J. AOAC Int., 84, 383-391, 2001. 

Determination of trichothecenes in duplicate diets of young children by capillary gas chromatography with mass spectrometric detection. Food Additives and Contaminants, Vol. 22, No. 1, (January 2005), 48-55, ISSN 0265-203X. 

Table 8 Major m/e signals in the mass spectra of some pesticides separated in gas chromatography with mass spectrometric detection (ionization by electron impact) ...

Quintana, J.B. Carpinteiro, J. Rodriguez, I. Lorenzo, R.A. Carro, A.M. Cela, R. Determination of natural and synthetic estrogens in water by gas chromatography with mass spectrometric detection. J. Chromatogr. A, 2004, 1024, 177-185. 

Mol, H.G.J., Sunarto,S., and Steijger, O.M. (2000) Determination of endocrine disrupters in water after derivatization with N-methyl-N-(tert-butyldimethyltrifluoroacetamide) using gas chromatography with mass spectrometric detection. Journal of Chromatography A 879,97-112. 

Rosenfeld JM, Moharir Y, Hill R. Direct solid-phase isolation and oximation of prostaglandin E2 from plasma and quantitation by gas chromatography with mass spectrometric detection in the negative-ion chemical ionization mode. Anal Chem 1992 63 1536-1541. 

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