Nitrosamines mass spectrometry

Confirmation of the identities of nitrosamines generally is accompHshed by gas chromatography—mass spectrometry (gc/ms) (46,87). High resolution gc/ms, as well as gc/ms in various single-ion modes, can be used as specific detectors, especially when screening for particular nitrosamines (87) (see Analytical LffiTHODS Trace and residue analysis). 

In a similar study, Gray et al. (60) investigated the possible formation of N-nitrosamines in heated chicken frankfurters which been prepared with various levels of nitrite (0-156 mg/kg). As expected, apparent N-nitrosamine levels increased with increasing concentrations of nitrite, but did not exceed 4 yg/kg except for two samples which contained 8 and II yg/kg of NMOR. The presence of these relatively high levels of NMOR was confirmed by mass spectrometry and raised the question as to its mode of formation. It was shown to be due to the morpholine present in the steam entering the smokehouse, as this amine is commonly used as a corrosion inhibitor in steam process equipment ( ). The detectable levels of NMOR in the Canadian study ( ) were also attributed in part to the use of morpholine as an anti-corrosion agent in the steam supply (62). 

The data in Table I are also significant in terms of the type of analysis to determine the presence of NDMA. In all cases analysis was done using gas chromatography coupled with a Thermal Energy Analyzer, a sensitive, relatively specific nitrosamine detector (12). Further, in six of the studies, the presence of NDMA in several samples was confirmed by gas chromatography-mass spectrometry (GC-MS). The mass spectral data firmly established the presence of NDMA in the beer samples. 

Reliable analytical methods are available for determination of many volatile nitrosamines at concentrations of 0.1 to 10 ppb in a variety of environmental and biological samples. Most methods employ distillation, extraction, an optional cleanup step, concentration, and final separation by gas chromatography (GC). Use of the highly specific Thermal Energy Analyzer (TEA) as a GC detector affords simplification of sample handling and cleanup without sacrifice of selectivity or sensitivity. Mass spectrometry (MS) is usually employed to confirm the identity of nitrosamines. Utilization of the mass spectrometer s capability to provide quantitative data affords additional confirmatory evidence and quantitative confirmation should be a required criterion of environmental sample analysis. Artifactual formation of nitrosamines continues to be a problem, especially at low levels (0.1 to 1 ppb), and precautions must be taken, such as addition of sulfamic acid or other nitrosation inhibitors. The efficacy of measures for prevention of artifactual nitrosamine formation should be evaluated in each type of sample examined. 

Confirmation of identity of nitrosamines via an independent detection system is desirable since a higher level of confidence is achieved if a different physical property or structural characteristic is measured. Mass spectrometry (MS) has been used... 

Boyd JM, Hrudey SE, Li XF, Richardson SD (2011) Solid-phase extraction and high-performance liquid chromatography mass spectrometry analysis of nitrosamines in treated drinking water and wastewater. Trends Anal Chem 30(9) 1410-1421... 

Munch JW, Bassett MV (2004) EPA Method 521. Determination of nitrosamines in drinking water by sohd-phase extraction and capillary column gas chromatography with large volume injection and chemical ionization tandem mass spectrometry (MS/MS), U.S. EPA, Cincinnati, OH. Available at www.epa.gov/nerlcwww/m 521.pdf... 

Zhao YY, Boyd J, Hrudey SE, Li XF (2006) Characterization of new nitrosamines in drinking water using liquid chromatography tandem mass spectrometry. Environ Sci Technol 40 (24) 7636-7641... 

Yuan YZ, Liu X, Boyd JM, Qin F, Li J, Li XF (2009) Identiflcation of N-nitrosamines in treated drinking water using nanoelectrospray ionization high-fleld asymmetric waveform ion mobility spectrometry with quadrupole time-of-flight mass spectrometry. J Chromatogr Sci 47(l) 92-96... 

The prototype of the tobacco specific nitrosamines, NNN, has been detected in both tobacco smoke and unburned tobacco. Various analytical methods have been used including gas chromatography (GLC) (13,14,15,16) combined GLC-mass spectrometry (17), thin layer chromatography (18) high pressure liquid chromatography (HPLC) (19,20), and combined HPLC-thermal energy analysis (21). 

HA, heterocyclic amine AA, aromatic amine PA, polyamine Al, aliphatic amine N, nitrosamine BCD, electrochemical UV, ultraviolet FL, fluorescence TSI, thermospray ionization ESI, electrospray ionization MS, MS-tandem mass spectrometry SIM, selected ion monitoring A, air H, water W, waste. 

Jansson, Ch., Paccou, A., and Osterdahl, B.-G., Analysis of tobacco-specific A -nitrosamines in snuff by ethyl acetate extraction and hquid chromatography-tandem mass spectrometry, J. Chromatogr., 1008, 135-143, 2003. 

The combination of LC and mass spectrometry (LC-MS) offers signihcant analytical advantages over the aforementioned techniques. The LC-MS technique can be used to separate and detect volatile and nonvolatile A -nitrosamines without the need of a solvent cold trap. It allows an increase in the use of polar mobile phases when comparing to LC-TEA. Moreover, the LC-MS technique allows the identihcation of unknown components. This is especially important in the analysis of nonvolatile A-nitrosamines, because contrary to volatile A-nitrosamines, the information regarding their occurrence and concentration in many products is not yet well known. 

Arrendale, R.E., W.J. Chamberlain, and O.T. Chortyk The quantitation of V-nitrosamines from tobacco using capillary GC/single ion monitoring (SIM)/mass spectrometry 36th Tobacco Chemists Research Conference, Program Booklet and Abstracts, Vol. 36, Paper No. 11, 1982, p. 6. 

Arrendale, R.F., W.J. Chamberlain, O.T. Chortyk, J.L. Baker, and M.G. Stephenson Determination of tobacco-specific A-nitrosamines by capillary gas chromatography/ selected ion monitoring mass spectrometry Anal. Chem. 58 (1986) 565-568. 

Zhang, J., C. Li, Z. Chen, Z. Rao, D. Wen, K. Li, and H. Liu Metabolism study on tobacco specific V-nitrosamines in rabbit by solid-phase extraction and liquid chromatography-electrospray interface-mass spectrometry method 60th Tobacco Science Research Conference, Program Booklet and Abstracts, Vol. 60, Paper No. 53, 2006, p. 48. 

While the chemiluminescence detectors have considerable selectivity for nitrosamines it must also be recognized that the possibility exists that any compound that can produce NO during pyrolysis will produce a signal (20). For example, TEA responses have been observed from organic nitrites, C-nitro and C-nitroso compounds (17,28) and nitramines (29). In the routine analysis of N-nitroso compounds, possible TEA analyzer responses to compounds other than N-nitroso derivatives normally do not represent a problem since the the identity of a compound can be readily established by co-elution with known standards on GC-TEA and/or HPLC-TEA systems (30-34). Additional confirmation could be provided when the sample can be chromatographed on both GC-TEA and HPLC-TEA (30,33). The technique accepted as the most reliable for the confirmation of N-nitrosamines is based on mass spectrometry (22, 35,36). Low-resolution mass spectrometry is satisfactory for the analysis of relatively simple mixtures and in those instances in which extensive clean-up of samples has been performed. However, complex samples require more sophisticated GC and MS procedures (e.g., high resolution-MS). 

Ross et al (42) employed TEA for detection of dimethylnitros-amine and dipropylnitrosamine in several herbicide formulations after separation by GC or HPLC. With additional chromatographic cleanup, the identity of the compounds was confirmed by high resolution mass spectrometry. These results further indicated that formulations of amine salts can form nitrosamines on storage and nitrosamines can be formed in preparations of nitroaniline based herbicides. The results obtained for the determination of nitrosamines in seven technical herbicides are shown in Table 8. 

Interest in alkaloids of the nicotine group appears to be on the increase. A review has appeared covering tobacco-specific nitrosamines, which may be causative factors in tobacco-related cancers. The solution conformation, and proton, deuterium, carbon-13, and nitrogen-15 n.m.r. spectra of nicotine and its 2- and 4-isomers, have been studied. A new synthesis of nornicotine and nicotine has been described, and a quantitative carbon-13 n.m.r. spectral analysis of nicotine that is labelled at positions 1, 2, and 3 with carbon-13 been presented. The synthesis and mass spectrometry of several structurally related nicotinoids have been reported. Nicotine is dehydrogenated on irradiation in benzene solution in the presence of benzophenone to l -methyl-2 -(3-pyri-dyl)pyrrole. ° Nornicotine has been synthesized in four steps from 3-bromo-pyridine and N-3-butenyl-phthalimide, using a palladium-catalysed vinylic... 

Munch, J.W. Revision 1.0, Sept. 2004, NERL Method 521 Determination of Nitrosamines in Drinking Water by Solid Phase Extraction and Capillary Column Gas Chromatography with Large Volume Injection and Chemical Ionization Tandem Mass Spectrometry (MS/MS). 

Gas chromatography-mass spectrometry has been applied to the determination of other types of orgaruc compounds in waste waters including the following (Table 16.9) hydrocarbons, phenols, organic halogen compounds, polychlorobiphenyls, chlorophenols, chlorinated tyrosine, nitrosamines, alkyl benzene sulphonates, N,N dialkyldithio-carbamates, volatile organic compounds. 

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