Radioactivity Monitoring

A sample was irradiated in a neutron flux and the induced radioactivity monitored after it was removed from the flux. The fully corrected results are presented below. 

The pattern of metabolites in bile (animals only) and in urine have been investigated using column chromatography (Amberlite XAD 2 and Sephadex DEAE), tic and reversed phase HPLC in combination with radioactivity monitoring. 

Isoflo HPLC radioactivity monitor, iso mix interface between HPLC column and Isoflo HPLC radioactivity monitor ... 

Heath, T. G. Mooney, J. P. Broersma, R. 1997. Narrow-bore liquid chromatography-tandem mass spectrometry with simultaneous radioactivity monitoring for partially characterizing the biliary metabolites of an arginine fluoroalkyl ketone analog of D-MePhe-Pro-Arg, a potent thrombin inhibitor. J. Chromatgr. B Biomed. Sci. Appl., 688,281-289. 

Finally, the combined use of HPLC techniques and GLC methodologies have given the same result as the radioactivity monitoring during the pharmacokinetic studies, based upon the knowledge of the physiocochemi-cal properties of A9-tetrahydrocannabinol. 

Figure 9.111 Adenylate kinase activity measured by the HPLC assay method. The assay mixture contained 200 fiM ATP, 20 fiM pH]AMP (approximately 120,000 cpm), 50 mM Tris-HCl (pH 7.4), and 32 fig of protein of the enzyme from Dictyostelium discoideum. Samples (20 juL) were injected and the radioactivity monitored continuously with a Berthold LB 503 detector using PICO-Fluor 30 scintillant. Absorbance was measured at 254 nm. Three representative time points were shown (A) 1 minute (B) 30 minutes, and (C) 60 minutes after initiation of the reaction. (From Rosso-mando, 1987.)... 

Reaction mixtures are chromatographed on a PolyHydroxyethyl Aspartam-ide column (4.6 mm X 100 mm) from Poly LC (Columbia, MD). Inorganic phosphate is not adsorbed to the column under the initial conditions (40 mM triethylamine-phosphoric acid, pH 2.8), while elution of ATP requires 800 mM triethylamine-phosphoric acid (pH 2.8). Initial conditions are maintained for 16 minutes and total run time was 30 minutes including reequilibration. Column effluent was monitored by a flow-through radioactivity monitor. 

Figure 9.138 Analysis of angiotensin II phosphorylation by tyrosine protein kinase from HL-60. A 30-/xL aliquot of incubation medium was analyzed. The black profile shows the radioactivity monitor (2500 mV full-scale output). The open profile shows the absorbance at 280 nm (sensitivity of detection 0.1 AUFS). (From Boutin et al., 1992.)...

Ferreri, G. and Surbeck, H., in Proc. Second Int. Meeting on Low-Level air Radioactivity Monitoring, Madralin, near Warsaw, Poland, 14-18 Feb. 1994. 

Meeting on Low-level Air Radioactivity Monitoring, Manderlin, near Warsaw, 14-18 Feb. 1994. 

The monitoring networks in countries with nuclear power plants have been in operation for a longer period of time. In many other countries attention to environmental radioactivity monitoring has been a result of the Chernobyl accident in 1986. Here we shall describe the situation in some of the countries. 

Fig. 9.14. Air radioactivity monitoring stations in Switzerland (after Ferreri and Surbeck, 1994). Circles low volume samples squares high volume samples.

Milles-Lacroix, J.-C., Bourlat, Y. and Masnier, R., Airborne radioactivity measurements in Montlhery (France), Presented at Second International Meeting on Low-Level Air Radioactivity Monitoring, 14-18 February 1994, Madralin (near Warsaw), Poland. 

The radio-HPLC equipment considered of 2 Waters model 6000 A pumps, a Waters 660 solvent programmer, a Waters U6K injector, a Varian Varichrom UV-VIS spectrophotometric detector, a FMI LB 5031 scintillation cocktail pump, a Berthold Radioactivity Monitor LB 504 fitted out with an 800-pl flow-cell and a Spectra-Physics SP 4100 computing integrator. Dried extracts were dissolved in minimal amounts of dimethylsulphoxide for injection. 

On-line HPLC radioactivity monitor (e.g., Berthold LB506C, Berthold, Leeds, UK). 

Fig. 6-25. Analysis of Sr-90 with the aid of a radioactivity monitor. - Separator column IonPac CS2 eluent 0.03 mol/L HC1 + 0.002 mol/L histidine hydrochloride flow rate 1.5 mL/min detection scintillation measurement for Sr-90 injection volume 50 pL solute concentration 76.4 Bq Sr-90 with inactive SrCl2 as the carrier.

C-pirlimycin. " C-Pirlimycin hydrochloride was synthesized by the sequence shown in Figure 2. Final purification was accomplished by recrystallization to a radiochemical purity >98% as measured by HPLC radioactivity monitoring techniques (HPLC/RAM). The specific activity of the purified material was 11.7 mCi/mmole. 

HPLC with radioactivity monitoring indicated eight radioactive peaks in the urine collected in the first sampling period (0-12 hour) after dose administration. For comparison,... 

Radioactivity Monitor. The homemade detector systems - where the detector loop is placed into a well-type scintillation detector - are frequently used (De Groot et al. 

The use of a dual detector system, which is a radioactive monitor with a UV detector working at 280 nm, is practical. The mobile phase is usually buffered water. 

Figure 14-7, Radioactive monitoring of wear lubricated with a compounded oil. Contact pressure 0,991 MPa, rubbing speed 10,6 cm/s, Additive ...

Fig. 2. Reverse phase HPLC of GAs. Column 250 x 5 mm i.d. 5 p,m ODS Hypersil Mobile phase 40 min, 40-90% gradient of methanol in 0.5 % aqueous acetic acid. Flow rate 1 ml min". Detector radioactivity monitor operating in homogeneous mode [66,67]. Sample ca. lOOOOdpm of each GA. [Crozier, unpublished data].

Fig. 12. HPLC-RC analysis of the metabolism of radiolabelled lAA conjugates by leaf discs from wild-type and RolB tobacco plants. After a 24 h metabolism period leaf discs were extracts with methanol and ca. 10 000 dpm aliquots were analysed by reverse phase HPLC-RC with column and flow rate, as in Fig. 6. Mobile phase 25 min, 10-60% gradient of methanol in 1% aqueous acetic acid. Detector radioactivity monitor operating in homogeneous mode [66,67]. Traces illustrate [ CJIAGluc metabolism by (A) wildBtype and (B) RolB leaf discs [ HJlAInos metabolism by (C) wildBtype and (D) RolB leaf discs [ C]IAAsp metabolism by (E) wildBtype and (F) RolB leaf discs [117],...

The Berthold radioactivity monitor (produced by Laboratorium Prof. Dr. Berthold, D-7547, Wildbad 1, Calmbacher Strasse 22) is the only on-line radiometric scintillation detection system suitable for HPLC that is commercially available. The monitor is offered with cells for heterogeneous scintillation counting or as pert of a homogeneous scintillation detector system. Flow cells filled with glass... 

Most radioactivity monitors use flow cells of different types positioned between two photomultiplier tubes which usually possess special reflectors to ensure high continuing efficiencies. The signal pulses from the photomultipliers are measured in coincidence to suppress contributions from noise and chemiluminescence. The signals from the photomultiplier tubes are amplified and are then usually subjected to various data reduction processes. 

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