14C-Toluene

Many investigators have also shown that toluene can be degraded under methanogenic conditions. The first report of this was that of Warder < / (1980) who measured a 5% 14C02 recovery and some methane from 14C-toluene after a 233-... 

H toluene, 14C toluene unknowns 14C toluene standard of known disintegrations per minute per milliliter Volumetric dispensing bottles Scintillation fluid (0.5% PPO in toluene)... 

This experiment tests your ability to determine the counts per minute of both 3H and 14C in a mixture that contains unknown amounts of 3H and 14C toluene. The unknown and a 14C toluene standard employed in the experiment are both equally quenched (by dissolved 02, etc.), so quenching differences do not influence the final result. The experiment can therefore employ measurement of counting efficiencies of the unknown and the stan-... 

Bottle A 0.1 ml of unknown radioactive toluene solution (unknown quantities of 3H and 14C) Bottle B 0.1 ml of standard 14C toluene solution... 

Sample 14C toluene standard of known dpm/ml Chloroform Quenched 14C unknown... 

H and 14C unknowns—In a fume hood, mix sufficient quantities of 3H-toluene, 14C-toluene and unlabeled toluene to obtain 2 to 10 nCi of 3H-toluene and 1 to 2 nCi of 14C-toluene per 0.1 ml of toluene solution. You will need 10 ml of this solution for 50 groups to perform the experiment. 

Long RM and Rickert DE, Metabolism and excretion of 2,6-dinitro[14C]toluene in vivo and in isolated perfused rat livers, Drug Metab. Dispos., 10, 455, 1982. 

C counting is performed on an Intertechnique SL-30 Liquid Scintillation Counter. Aliquots of samples of recovered 14C BaA and 14C BaP are assayed for 14C. Counting efficiency is determined by recounting after the addition of an aliquot of a standardized 14C toluene solution. 

Fig 1 Quenching of the Scintillation Process by Organic Nitrocompounds in Toluene-14C-PPO... 

In the production of TNT from the reaction between toluene and mixed acids (nitric/sulfuric), TeNMe forms in amounts between 0.2—0.4% of the total wt of TNT. This TeNMe has been held responsible for several expins which have occurred in TNT plants, causing fatal injuries to personnel and severe damage to facilities. These expins were attributed to the presence of TeNMe in the acid fume lines and the acid storage tanks. Mixts of TeNMe and readily oxidizable materials are known to form very powerful and sensitive expl mixts. Since TeNMe is also isolated from the nitration of Nitrobenzene (NB), the TeNMe formed in the nitration of toluene may arise from the oxidation of the aromatic ring and/or methyl group. In an effort to gain more informa-. tion on the origin of TeNMe from TNT production, radioactive carbon-14 (14C) was used as a tracer to determine the extent to which each of the carbon atoms in the toluene skeleton of the various nitro-substituted isomers contributes to... 

The contribution of the carbon atoms from the 1- and 7- positions to TeNMe carbon were obtained by determining the specific activity of the TeNMe isolated from the nitration of toluene-1-14C and toluene-7-14 C, respectively. Similarly, by nitrating toluene-1,3,5-l4C, it was possible to determine the 3- and 5-contributions, since the contribution of the 1-position could be subtracted and the 3- and 5-positions were considered to be equivalent. Finally, the contributions of the 2-, 4- and 6-positions were determined from the nitration of toluene-2,4,6,7-14C by subtracting the contribution of the 7-position. An approximate contribution for each of these positions (2-, 4- and 6-) was obtained by considering them to be equivalent... 

The activity of the polymers was determined in toluene solution with Koch-Light KL.356 xylene-based scintillator in 4 ml glass vials, at an efficiency of 24% for tritium and 75% for 14C by means of an IDL liquid scintillation counter type 6012. 

The supemate thus obtained containing unbound chlordiazepoxide-14C is decanted into a counting vial and toluene is added, and... 

Phenol can also be prepared by the decomposition of benzoic acid prepared by the oxidation of toluene.927,978 The process is an oxidative decarboxylation catalyzed by copper(II). An interesting feature of this reaction is that the phenolic hydroxyl group enters into the position ortho to the carboxyl group as was proved by 14C labeling.979 In the Dow process980 molten benzoic acid is transformed with steam and air in the presence of Cu(II) and Mg(II) salts at 230-240°C. A copper oxide catalyst is used in a vapor-phase oxidation developed by Lummus.981... 

The subject of natural benzaldehyde came to the forefront in 1984 when it was found that a natural benzaldehyde product, labeled "oil of benzaldehyde," was actually made synthetically by the air oxidation of toluene followed by careful fractionation to remove trace impurities. This finding was accomplished by the Center for Applied Isotopic Studies, University of Georgia, and involved measuring the amounts of 13C and 14C in that material. 

Confirmation of this proposed pathway was established by Altenschmidt Fuchs (1991, 1992) in their study of the biochemistry of toluene decay by the denitrifying Pseudomonas sp. strain K172. These investigators confirmed the presence of benzyl alcohol dehydrogenase, benzaldehyde dehydrogenase, and benzoyl-CoA synthetase in cell-free extracts of this isolate. Further, [14C]benzyl... 

Established Exemption Levels. NRC s radiation protection standards in 10 CFR Part 20 (NRC, 1991) include limits on concentrations or annual releases of radionuclides for unrestricted discharge into sanitary sewer systems, except any excreta from individuals undergoing medical treatment with radioactive material are exempt from the limits. These regulations also include an exemption for land disposal of liquid scintillation materials and animal carcasses that contain 2 kBq g 1 (0.05 pCi g-1) or less of 3H or 14C, although the exempted scintillation materials must be managed in accordance with RCRA requirements due to the presence of toluene. 

Fig. 9.17 UV-visible absorption spectra of 13c (black), 14c (grey) and H2P — 15c (blue) in toluene solution...

Eckernas and Aquilonius described a simple radioenzymatic procedure for the determination of choline and acetylcholine in brain regions of rats sacrificed by microwave irradiation [215]. The methods are based on acetylation (in phosphate buffer) of free choline with [14C]-acetylcholine using purified choline acetyltransferase. After ion-pair extraction of [14C]-acetylcholine with tertiary phenyl borate contained in toluene-based scintillation cocktail, the radioactivity was measured. 

---