Counting liquid scintillation

Liquid scintillation counting is by far the most common method of detection and quantitation of -emission (12). This technique involves the conversion of the emitted P-radiation into light by a solution of a mixture of fluorescent materials or fluors, called the Hquid scintillation cocktail. The sensitive detection of this light is affected by a pair of matched photomultiplier tubes (see Photodetectors) in the dark chamber. This signal is amplified, measured, and recorded by the Hquid scintillation counter. Efficiencies of detection are typically 25—60% for tritium >90% for and P and... 

The emitted P particles excite the organic molecules which, in returning to normal energy levels, emit light pulses that are detected by a photomultiplier tube, amplified, and electronically counted. Liquid scintillation counting is by far the most widely used technique in tritium tracer studies and has superseded most other analytical techniques for general use (70). 

Bransome, Jr, Ed, The Current Status of Liquid Scintillation Counting , Grune Stratton, NY (1970) 7) D.L. Horrocks C.T. Peng, Eds,... 

Organic Scintillators and Liquid Scintillation Counting , Academic Press, NY (1971)... 

E. Rapkin, Guide to Preparation of Samples for Liquid Scintillation Counting , New England Nuclear Corp, Boston, Mass (1975)... 

In the carbon-14 expts, HMX/RDX product was isolated qualitatively, separated Into its components, and each component assayed for carbon-14 beta radioactivity using a liquid scintillation counting technique (Ref 11). DPT-l4C was isolated as an intermediate product from the reaction mixt and similarly radioassayed. For the nitrogen-15 tagged AN expts, HMX and RDX were assayed mass spectrometrically for i5N/i4N ratios from which atom %1SN contents were calcd. In die course of these expts, each tagged species was added initially and also at subsequent stages of the reaction process. The important observations and results are summarized as ... 

Since cigarette tobacco already contains several micrograms of the TSNA, we determined the transfer rate of NNN into the smoke by spiking the tobacco column with NNN-2 - C. The smoke from such radiolabeled cigarettes is then analyzed by HPLC and the amount of unchanged NNN-2 - C is determined by liquid scintillation counting. Independent of the smoke pH, about 11% of the radioactive NNN is found in the mainstream smoke thus 41-46% of mainstream smoke NNN stems from the tobacco NNN and 54-59% are pyrosynthesized (11). 

Liquid chromatography/mass spectrometry Lower limit of detection Limit of detection Limit of quantitation Florseshoe crab hemocyanin Liquid scintillation counting Matrix-assisted laser desorption/ ionization mass spectrometry m -Maleimidobenzoy 1-A -Hydroxysuccinimide 1 -Cyclohexyl-3-(2-Morptiolino-ethyl)carbodiimide rnetlio-/ -Toluenesulfonate (same as CDI)... 

Using a simple solvent extraction procedure to minimize matrix effects, a diclofop-methyl immunoassay was developed for milk, a number of edible plant products, and other matrices. Gas chromatography (GC) and liquid scintillation counting (LSC) of a C-labeled analyte were used as reference methods to compare with enzyme immunoassay (EIA) results. The methods were well correlated, with comparison of EIA... 

Guilmette RA, Bay AS. 1981. Radio assays of americium or curium in biological material by isoctyl acid phosphate solvent extraction and a liquid scintillation counting. Anal Chem 53 2351-2354. 

Analytical Methods. Liquid scintillation counting (LSC) was done using Packard Models 3375 and 3380 Liquid Scintillation Spectrometers equipped with automatic external standards. Solid samples were combusted in a Packard model 306 Sample Oxidizer prior to LSC analysis. 

Liquid scintillation counting has been used frequently for the measurement of environmental technetium. The specimens to be analyzed are treated by chemical procedures to obtain a technetium-bearing sample solution, which is mixed with a cocktail for scintillation counting. A low background scintillation counter with an anticoincidence system can be used for high precision measurements at a detection limit of 1-25 mBq. 

R. C. Garner, J. V. Garner, S. Gregory, M. Whattam, A. Calam, D. Leong. Comparison of the absorption of micronized (daflon 500 mg) and nonmicronized 14C-diosmin tablets after oral administration to healthy volunteers by accelerator mass spectrometry and liquid scintillation counting. J. Pharm. Sci. 2002, 91, 32— 40. 

To determine the efficiency of aminoacylation of [14C]Phe-tRNA, 5 fil aliquots of the aminoacylation mixture are withdrawn before and after the reaction the samples taken from the reaction mixture at the end of the incubation are spotted onto 3-MM paper discs (Schleicher Schuell) and processed by the cold TCA precipitation method, while the sample taken before the reaction is spotted on a paper disc pretreated empty by the same cold TCA procedure. Determination of the radioactivity present on these filters by liquid scintillation counting allows one to calculate the aminoacylation efficiency of the reaction (which, for phenylalanine, should be >2% of total tRNA). The specific activity of the [14C] Phe-tRNA can be determined after one-step purification of Phe-tRNA by BD cellulose chromatography (Gillam et al., 1968), followed by determination of the radioactivity and of the A260. 

At the end of the aminoacylation reaction, a 5-fA aliquot of the reaction mixture is spotted onto a 3MM paper disc (Schleicher Schuell) that is immediately placed in 10% ice-cold TCA for 30 min. After three washes in 5% TCA at room temperature for 5 to 10 min, the filter is placed in an ethyl ether ethanol (1 1) mixture for 10 min and then in ethyl ether for 10 min before being dried under an infrared lamp. The amount of radioactivity precipitated on each filter is finally determined by liquid scintillation counting. 

In municipalities where the water supplies are from deep-bored wells, samples of household water were collected for Rn-222 analyses. The water samples were analysed by liquid scintillation counting. The method for sampling and sample preparation were adopted from Partridge et al (1979). 

Formation and transport of radon ) In the present work, lead isotopes were chemically separated from the sample gas as lead sulfide since the formation of lead sulfide was inevitable under the presence of H2S in the fumarolic gas. The lead sulfide was then dissolved in a small amount of concentrated HCI and mixed with the Insta Gel(emulsion scintillator solution, Insta Gel, Packard Inc.) for the liquid scintillation counting. The chemical yield and the volume of the collected non-condensing gas were obtained from the measurement of the activities of Pb-214 and its progeny which were in radioequilibrium with their precursor Rn-222 whose concentration was determined separately by the direct method. 

H.A. Polach, Evaluation and status of liquid scintillation counting for radiocarbon dating, Radiocarbon 29, 1 11 (1987) H.A. Polach, Liquid scintillation C 14 spectrometry errors and assurances, Radiocarbon 31, 327 331 (1989). 

Hercules, D. M. in E. D. Bransome (ed.). Current status of liquid scintillation counting, in press. 

On the other hand, nonspecific analytical methods (such as liquid scintillation counting, spectrophotometry, and titration procedures) may not distinguish between the solute under study and certain impurities. When using such methods, the solid state of interest should be highly pure and the amount of solid in excess of that required to saturate the solution should be minimized. 

To determine 63 Ni in seawater the nickel was adsorbed on to hydrous manganese dioxide and the precipitate dissolved in hydrochloric acid. The nickel was then extracted with diethyldithiocarbamate in chloroform and determined by liquid scintillation counting [527]. 

Hiraide et al. [68] used continuous flow coprecipitation-floatation for the radiochemical separation of cobalt from seawater. The 60cobalt activity was measured by liquid scintillation counting with greater than 90% yield and a detection limit of 5 fCi/1 seawater. 

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