Liquid scintillation analysis

The reactivity of compounds such as 28 was clearly demonstrated by the peroxidase-catalyzed covalent binding of A -methyW-hydroxyellipticine (27) to proteins (756). Using horseradish peroxidase and hydrogen peroxide, tritiated-27 was converted to the 9-oxoellipticine derivative in the presence of bovine serum albumin (BSA) and human antibovine IgG in vitro. Covalent binding to these proteins was confirmed by gel electrophoresis, combustion, and liquid scintillation analysis. Dissolution of the BSA-ellipticinium derivative with pronase and... 

Zhu [58] described the use of liquid scintillation analysis for the monitoring of a-emitting and transuranium nuclides in environmental samples. 

Noor, A., M. Zakir, B. Rasyid, Marning, and M.F. L Annaunziata. 1996. Cherenkov and liquid scintillation analysis of the triple label 86Rb-35S-33P. Appl. Radiat. Isot. 47 659-668. 

Figure 7. Semilogarithmic plots of fraction of the b -THC, 2.0 mg/kg dose/mL of plasma, vs. time for Dog A from (O), the liquid scintillation analysis of the total I4C collected as ts -THC on normal-phase HPLC and from (9), the electron-capture GLC of the derivatized HPLC collected fraction. The values were corrected for the fractions of extracts and total collection range used (15).

Liquid Scintillation Analysis Water, swipes or air samples 30 20... 

Quantities of plutonium-241, a beta-particle emitter, can be quantified from (1) assumed isotopic abundance ratios, (2) estimated in-growth of its progeny americion-241 by gamma spectrometry, or by (3) mass spectrometry (Bernhardt 1976). Americium-241 is produced from the beta decay of plutonium-241 and, therefore, can be used to indirectly measure the concentration of plutonium-241 (Metz and Waterbury 1962). Direct determination of plutonium-241 by measurement of its low energy beta-particle decay has been reported using liquid scintillation analysis (Martin 1986). 

Acid extracts were combusted for 2 min in a Packard, Tricarb Model 306 sample oxidizer. Three 0.5-ml aliquots of each of the cooled sulfuric acid extracts were transferred into combustion cones containing a paper absorbent. About 0.1 g of Combust Aid was added immediately prior to placement in the combustion basket of the oxidizer. Labeled C02 was trapped in Carbo-Sorb (approx. 7 ml) and scintillation cocktail containing Permafluor V (about 13 ml). Radioactivity was measured by liquid scintillation analysis in a Beckman LS 6800 counter and corrected for efficiency and recovery. Data collected as dpm s were converted to mg based on the amount of paraquat ion in the original spray solution. 

Radioactive metabolites are often separated by electrophoresis on polyacrylamide gels. The subsequent liquid scintillation analysis of the radioactivity is usually performed after treatment with some quarternary ammonium base solubilizer. 

Another way of attack is to carry out the liquid scintillation analysis with the substance in situ. With such a method the radioactive substance is retained in the gel, is easy to handle and is not lost for further analysis. 

Recently, the Yankee Atomic Electric Company, Environmental Laboratory, has determined the tritium levels in water samples from the environs of several nuclear generating facilities in the New England area by liquid scintillation analysis of high purity tritiated benzene prepared from the water samples to be quantified. A commercially available unit was utilized to facilitate the synthesis of benzene by reacting the water sample with calcium carbide to form tritiated acetylene which is subsequently trimerized on a vanadium catalyst to high purity tritiated benzene. 

Kessler MJ (1989) Liquid scintillation analysis. Packard Instruments, Meriden... 

One aluminum strip was removed each month and the amount of " C-labled oil in the RTVll was measured by thermal oxidation, based on 3-5 samples. This process is described in a report by J. Carpenter (9). The total amount of oil in each coupon was calculated based on the total weight of the silicone topcoat for a specified aluminum coupon. In addition, the amount of in the water and sediment was determined by liquid scintillation analysis and thermal oxidation/ liquid scintillation analysis, respectively. 

The sampling of solution for activity measurement is carried out by filtration with 0.22 pm Millex filter (Millipore Co.) which is encapsuled and attached to a syringe for handy operation. The randomly selected filtrates are further passed through Amicon Centriflo membrane filter (CF-25) of 2 nm pore size. The activities measured for the filtrates from the two different pore sizes are observed to be identical within experimental error. Activities are measured by a liquid scintillation counter. For each sample solution, triplicate samplings and activity measurements are undertaken and the average of three values is used for calculation. Absorption spectra of experimental solutions are measured using a Beckman UV 5260 spectrophotometer for the analysis of oxidation states of dissolved Pu ions. 

Radioactivity Analysis. Samples of urine, feces, and tissues were combusted to COo and analyzed for radioactivity (5). By using this method the recovery of radioactivity from samples spiked with C was 95 dt 5%. To determine the radioactivity expired as CO2, 5-ml aliquots of the solution used to trap the CO2 were added to 15 ml of a scintillation counting solution containing 4 grams 2,5-diphenyloxazole (PPO) and 0.1 grams l,4-bis-2(5-phenyloxazolyl)-benzene (POPOP) per liter of 1 1 toluene 2-methoxyethanol. Samples were counted for radioactivity in a Nuclear Chicago Mark II liquid scintillation counter. Counting eflSciency was corrected by the internal standard technique. 

For the analysis of americium in water, there is a broad array of sample preparation and detection methodologies that are available (see Table 7-2). Many of the common and standardized analytical methodologies typically include the minimization of sample volume, purification through co-precipitation, anion exchange column chromatography, and solvent extraction techniques followed by radiochemical detection of americium in the purified sample. Gross alpha analysis or liquid scintillation are common... 

DOE. 1995b. Separation and analysis of actinides by extraction chromatography coupled with alpha liquid scintillation spectrometry. Washington, DC U.S. Department of Energy. NTIS/DE96060013. 

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. 

The suppression and recovery of protein synthesis from DTT treatment (without cycloheximide treatment) can be monitored via metabolic pulse radiolabeling of cell cultures using [35S]-methionine and subsequent determination of radiolabeled protein content either by SDS-PAGE/ phosphor-imager analysis or liquid scintillation of tricholoroacetic acid insoluble material (Stephens et al., 2005). 

Procedures for pretreatment of soil samples and synthesis of sample benzene for 14C analysis had been described in Chen et al. (2002b). Sample benzene was often left for 3-4 weeks to allow any radon with half-life of 3.82 days that may be present to decay. 14C activity of the CgFL was then determined using a 1220-QUANTULUS ultralow-level liquid scintillation spectrometer manufactured by WALLAC Company, Sweden. The 14C analyses were conducted at the Guangzhou Institute of Geochemistry, CAS. Results are reported as A14C, in parts per thousand of the 14C/12C ratio from that of the standard (oxalic acid decay corrected to 1950) (Stuiver and Po-lach 1977), and corrected for bomb 14C (Chen et al. 2002b), where ... 

Scintillation counters, which constitute an extremely important group, depend upon the absorption of radiation by a scintillator to produce UV light scintillations, which are detected and converted into amplified voltage pulses by a photomultiplier (Figure 10.10). Solid scintillators are used extensively for the detection and analysis ofy-rays and X-rays, while liquid scintillators find widespread employment in the measurement of pure negatron emitters, especially where the particle energy is low (< 1 MeV). 

Groundwater age at each NGMP site has been assessed using multiple tracers. Tritium was analyzed in a 1 L unfiltered unpreserved sample using 70-fold electrolytic enrichment prior to ultra-low level liquid scintillation spectrometry (Morgenstern Taylor 2005). Samples for analysis of CFCs and SF6 (125 ml and 1 L, respectively) were collected in strict... 

Fish. Initial reports to determine NP in fish referred to the non-specific analysis of 14C-labeled compounds administered in exposure experiments. Granmo and Kollberg [7] used a solubiliser employing pancreatic enzymes to extract 14C-labeled NP from exposed cod and analysed it by liquid scintillation counting. 

Sampling and Analysis. Water samples (triplicate 1 ml) were taken at 2-day intervals and analyzed by standard liquid scintillation (LS) methods for total l C ioO ml samples were taken 2, 5, 9, 15, 22, 30, 43, 48, and 58 days after the start of the experiment, these were extracted twice with 50 ml of ethyl acetate hexane (7 3 v/v) and the extracts were reduced to 20 ml and analyzed by LS and TLC. 

The apparent retinal influx clearance,. Kin,retina expressed as mL/(min g retina), of the test substrate labeled with either [3 H] or [14C] from the circulating blood to the retina is determined by integration plot analysis. In brief, rats are anesthetized, followed by injection of the test substrate (e.g., an [3H]-labeled compound, about 10 /u.Ci/head) into the femoral vein. After collection of plasma samples, rats are decapitated and the retinas removed. The retinas are dissolved in 2 N NaOH and subsequently neutralized with 2 N HC1. The radioactivity of retinal cell lysates is measured by liquid scintillation spectrometry. As an index of the retinal distribution characteristics of the radiolabeled test substrate, the apparent retina-to-plasma concentration ratio (Vd) as a function of time is used. This ratio [Vd(Q] (mL/g retina) is defined as the amount of [3H] per gram retina divided by that per milliliter plasma, calculated over the time-period of the experiment. The Kjn,retina can be described by the following relationship ... 

Sampling and Analysis Water samples (triplicate 1-ml) were taken at 2-day intervals and analyzed by standard liquid scintillation (LS) methods for total Larger water samples (100 ml)... 

Traditionally, HAT activity is measured with a discontinuous radioactive filterbinding assay, which uses pH]acetyl-CoA as a histone acetyltransferase substrate [46]. The transfer of [ H]acetyl-groups to the histone substrate by histone acetyltransferases is detected by liquid scintillation counting of pHjacetylated histones, which are retained on a phosphocellulose disk. Due to its discontinuous character, this assay is technically problematic and not ideal for kinetic analysis. Hence, other assays that work with radiolabeled acetyl-CoA have been described that are suitable for a higher throughput. These work with streptavidin-covered beads [47] or a variant of the SPA with microtiter plates that contain a scintillant (FlashPlates) [48]. But as all these protocols are based on radioactively labeled substrates, they apparently show the same disadvantages that were described for the radioactive HDAC assay protocols. Therefore, nonradioactive assays have been developed to study histone acetyltransferase activity. 

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