Ix

(c) 2nd dimension chromatograms FIGURE 3.25 The concept of multidimensional GC.26 (a) Single heart-cut GC analysis, in which a portion of the effluent from the primary column containing analytes of interest is diverted to the second dimension column and subjected to additional separation over an extended period of time. (b) Dual heart-cut GC analysis, in which two regions with coelutions are diverted to the second dimension column, with less time to perform each separation. (c) Comprehensive...

N

(NNK) figure 12.1 Structures of some nitrosamines. reactions. The optimum pH for the nitrosation of most secondary amines is between 2.5 and 3.5, depending on the pof the amine under consideration.7 Tertiary amines react with the nitrosating agents in an acidic aqueous solution to form A -nitrosamines but, in general, only after the complete formation of dialkylamines through dealkylation. In the presence of a nucleophilic anion such as I, Br, CI, SCN, acetate or phthalate, nitrous acid can be...

Ultrasonic Extraction USE

Ultrasound-assisted extraction is a solid-liquid leaching technique done in the batch mode. Solvent is added to samples before they are placed in a sonication bath. The procedure is usually repeated two or three times for quantitative extraction. Ultrasonication produces very localized, extremely high effective temperatures that increase extraction efficiencies of solvents, yet it is inexpensive and fast. Combined extracts are centrifuged or filtered, cleaned up, and concentrated by SPE or LLE...

Soxhlet Extraction

US EPA Method 3540 is for the Soxhlet extraction of nonvolatile and semivolatile organic pollutants from environmental solids and solid wastes.141 Solid samples are mixed with anhydrous sodium sulfate and placed in an extraction thimble inside a Soxhlet extraction apparatus. The Soxhlet apparatus allows the solvent to be distilled and recycled through the system thereby introducing fresh solvent with each cycle. Concentration and solvent exchange are usually required before analysis. Surrogate...

Info

Cadaverine

Figure 9.3 Total gas chromatogram obtained from standard heterocyclic amines containing 5 ng of each amine . GC conditions-peaks 1. 2-amino-9H-pyrido 2,3-b indole AaC 2-aminodipyrido 1,2-a 3 7 -d imidazole Glu-p-2 2. Glu-P-1 3. Trp-P-1 4. 3-amino-1-methyl-5H-pyrido 3,4-b indole Trp-P-2 5. IQ 6. MelQ 7. MelQx 8. 4,8-DiMeIQx 9. PhIP 10. 4,7,8-TriMeIQx . Reproduced with permission from Kataoka, H. and Kijima, K. J. Chromatogr. A, 767, 187-194, 1997. Copyright 1997, Elsevier Science. procedure...

Amines And Nitrosamines

Extensive research has been done on the determination of amines including aromatic, aliphatic, alkyl, poly, glyco, biogenic amines and nitrosamines by various chromatographic methods in which many applications are based on the derivatization procedures adopted through different detection systems. The determination of aromatic amines has been carried out by capillary zone electrophoresis CZE , High-performance Liquid chromatography HPLC , GC, or GC-mass spectrometry with selected ion monitoring...

Undergoes Violent Collapse

FIGURE 2.29 Development and collapse of cavitation bubbles. Reprinted from Mason, T. J., Sonochemistry, Oxford University Press, Oxford, 1999. With permission. The most significant experimental variables are119 External applied pressure The formation of cavitation bubbles decreases with increasing ultrasonic frequency. A simple qualitative explanation of this effect could be that, at very high frequency the rarefaction and compression cycle is extremely short and the formation of a cavity in...

Ammonia

Ammonia is principally manufactured by direct synthesis from nitrogen and hydrogen using promoted iron catalysts, although it is also obtained commercially cheaply as a byproduct in the manufacture of coke and gas from coal. Ammonia is largely used in agriculture as fertilizer e.g., ammonia and solutions, ammonium nitrate, ammonium sulfate, ammonium phosphates, urea , in the production of nitric acid by oxidation of anhydrous NH3 , in the lead chamber process for manufacturing sulfuric acid, in...

5-dimethylaminonaphthalene-l-sulfonyl Mass Spectrometry

Figure 11.6 Separation of primary, secondary, and tertiary amines. R, R', R, alkyl or aryl. From Kataoka, H., j. Chromatogr., 733, 19-34, 1996. figure 11.7 Selective derivatization of primary and secondary amines with OPA and DETPC. R, R , alkyl or aryl. From Kataoka, H., J. Chromatogr., 733, 19-34, 1996. usually done by perfluoracylation of the amines, and the derivatives can be detected by ECD or mass spectrometry MS . However, many of the reagents in use for perfluoracylation need a strictly...

Experimental Conditions Required for NO2 or NO Analysis

Porapak Hydrogen Nitrogen

Fluropak-80, 10 SF-96 at 250 Carrier Scavenger Pulse internal Detector temperature Sample size Retention time 0.5 ml, 5.0 ml 02, 1.6 min NO, 1.6 min NO2, 2.3 min Reproduced with permission from Chromatography of Environmental Hazards. Copyright 1973, Elsevier Science. column, or preferentially by direct injection of NO2. Tables 9.4 and 9.5 give the experimental conditions required for NO and NOX analysis. Phillips and Coyne108 separated NO and NO2 in a variety of nitrogen...

Iii

Figure 10.10 GC-NICI-MS and GC-EI-MS ion currents SIM mode for components with molecular mass of 258 and corresponding sulfur-selective GC-AED chromatogram. From Becker, G., Nilsson, U., Colmsjo, A., and Ostman, C., J. Chromatogr. A, 825, 57-66, 1998. figure 10.10 GC-NICI-MS and GC-EI-MS ion currents SIM mode for components with molecular mass of 258 and corresponding sulfur-selective GC-AED chromatogram. From Becker, G., Nilsson, U., Colmsjo, A., and Ostman, C., J. Chromatogr. A, 825, 57-66,...

References

R., Measurement of trace aromatic amines in seawater using highperformance liquid chromatography with electrochemical detection, J. Chromatogr., 348, 265-274, 1985. 2. Sparking, G., Renman, L., Sango, C., Mathiasson, L., and Dalene, M., Capillary gas chromatographic method for the determination of complex mixture of isocyanates and amines, J. Chromatogr., 346, 191-204, 1985. 3. Pieraccini, G., Luceri, F., and Moneti, G., New gas-chromatographic...

Experimental Parameters for GC Analysis of Trace Contaminants in Liquid Ammonia

6 ft X i in. o.d., 0.028 in. gage stainless steel molecular sieve 5 A Thermal conductivity thermistor at 15 mA 600 C Ambient 600 C 50 ml min 0.5 in. min 18 ft X 1 8 in., 0.028 in. gage stainless steel 8 ft. porapak R, 80-100 mesh and 10 ft. porapak R, 80-100 mesh, with 10 PEI Thermal conductivity thermistor at 15 mA 800 C Ambient 800 C 70 ml min 0.5 in. min Thermal conductivity thermistor at 15 mA 600 C Ambient 800 C 50 ml min 0.5 in. min Reproduced with permission from Chromatography of...

Liu H Dasgupta P 1996 Analytical Chem 68 1817-1821

Valc rcel, M., Principios de Qu mica Anal tica, chaps. 4 and 7, Springer-Verlag Iberica, Berlin, pp. 175-239 and 337-365, 1999. 2. Grasselli, J. G., Undergraduate education in analytical chemistry level in the US-industrial needs 200, In Euroanalysis VII. Reviews on Analytical Chemistry, Malissa, H., Ed., Springer Verlag, Berlin, 1991. 3. Grasselli, J. G., The Analytical Approach, American Chemical Society, Washington, 1983. 4. Liu, H. and Dasgupta, P. K., Analytical chemistry in a drop....

Refrigerant

Focussed Microwave Assisted Extraction

FIGURE 2.27 Focused microwave-assisted Soxhlet extractor. Reprinted fromLuque-Garcia, J. L. and Luque de Castro, M. D., Trends Anal. Chem., 22, 90-98, 2003. With permission from Elsevier. FIGURE 2.27 Focused microwave-assisted Soxhlet extractor. Reprinted fromLuque-Garcia, J. L. and Luque de Castro, M. D., Trends Anal. Chem., 22, 90-98, 2003. With permission from Elsevier. includes an orifice atbottom of the irradiation zone enabling connection of the cartridge compartment to the distillation...