Radio-HPLC

Arukwe et al. [15] dosed Atlantic salmon with radioactive labeled NP. Fish were frozen immediately until gall bladder, skin, kidney, gill, liver, muscle, fat, remaining carcass and viscera were sampled and analysed. Tissue radioactivity was analysed by liquid scintillation counting after combustion of aliquots in an oxidiser apparatus. Metabolites (biliary and urinary) were separated by radio-HPLC. 

Lee, D. Y., Anderson, J. J., and Ryan, D. L. (2000). LC-ARC A novel sensitive in-line detection system/method for radio-HPLC. Paper presented at the 7th International Symposium of IIS, Dresden, Germany. 

Nassar, A. E., and Lee, D. Y. (2007b). Novel radio-HPLC detector for sensitive metabolite profiling and structural elucidation in support of drug metabolism studies. Drug Metab. Rev. 39(Suppl. 1) 73. 

Figure 6.13 Examples of the application of normal-phase, radio-HPLC to the analysis of de novo biosynthetic pathways in bark beetles (Scolytidae). Demonstration of sex-specific de novo biosynthesis of ipsenol, ipsdienol, and amitinol through radio-HPLC analysis of pentane extracts of Porapak-trapped volatiles from (A) male and (B) female Ips paraconfusus Lanier feeding for 168 h in Pinus ponderosa and (C) male and (D) female Ips pini (Say) feeding for 168 h in Pinus jeffreyi (Seybold et al., 1995b). Demonstration of sex-specific de novo biosynthesis of frontalin through radio-HPLC analysis of pentane extracts of Porapak-trapped volatiles from (E) male and (F) female...

Fig. 7 Radio-HPLC chromatogram for RP444 and the complex [99mTc(HYNIC-D-Phe)(TPPTS)(tricine)]...

Fig. 9 Radio-HPLC chromatogram for the chirality experiment. The single peak at 12.5 min is due to [99mTc(HYNIC-BA)(tricine)(PSA)], where HYNIC-BA is AT-benzyl-6-(2-sulfobenz-aldehydehydrazono)nicotinamide and PSA is pyridine-3-sulfonic acid, and the peaks at 19.8 and 20.4 min are from [99mTc(HYNIC-MBA)(tricine)(PSA)], where HYNIC-MBA is N-((R) (+)-a-methylbenzyl)-6-(2-sulfobenzaldehydehydrazono)nicotinamide...

Fig. 7 Typical radio-HPLC chromatograms of 90Y-TA138 (top) and mIn-TA138 (bottom)...

The mixture of anomers of 3, 5 -dibenzyl-2 -deoxy-2, 2 -difluorocytidine 76 obtained has been separated by crystallization from ethyl acetate. Deprotection with methanolic ammonia yielded 71b containing, after radio-HPLC, 99.8% of the desired / -isomer of >99.4% radiochemical purity. The overall radiochemical yield was 10.2%. 

Purification of the radiopharmaceutical, usually by semipreparative radio HPLC or solid-phase extraction... 

Azaconazole, C4abelled at the 2-caibon of the dioxolane ring (Fig. 1), was obtained from the Janssen Radiosynthesis Group. It showed a specific activity of 449 kBq/mg (12.1 pCi/mg) and a radiochemical purity exceeding 96%, as determined by radio-HPLC. The impurity was C-R 33 277, the 4H-1,2,4-triazole isomer of azaconazole. Unlabelled azaconazole was found to have a purity in excess of 99%. 

Total Suspended Matter (TSM) and the Standard Plate Count (SPC) of the sludge mixed liquor were ascertained. For the effluents, the Total Filtrable Residue (TFR), and the concentration of azaconazole (GLC-method) were measured. Radio-HPLC was used to monitor the presence of transformation products. The pH of the... 

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. 

RadioilPLC revealed the presence of R 28 644, the parent substance, and R 33 277, its isomeric triazole analogue, in the soil extracts. The ratio of 1,2,4-triazole 1,3,4-triazole remained virtually unchanged during the whole incubation period and equal to that of the C-synthesis product. No transformation products reached levels exceeding 1.0% of the extracted radioactivity. A typical radio-HPLC elution profile of a soil extract is ven in Fig. 4. At t = 300 days, the extracted radioactivity contained 97.4% azaconazole (RT = 36.16 min), 2.3% R 33 277 (RT = 34.91 min), and 0.3% of an unknown transformation product. 

The amount of extracted radioactivity per gram of oven-dry soil declined as a function of incubation time (Fig. 3). Since radio-HPLC proved that virtually that virtually all the extracted radioactivity was due to unchanged test substance (Fig. 4), the extent of depletion of extracted radioactivity was used to calculate the parent substance halfJife. The application of first-order kinetics equations [11]... 

Radio-HPLC analysis of day-7 and day-16 sewage revealed that respectively 96.6% and 97.7% of the chromatographed radioactivity was azaconazole- C, whereas the remainder was the synthesis by-product C-R 33 277. In effluents, collected on day 9 and day 14, respectively 96.7% and 96.1% of the chromatographed radioactivity was unchanged azaconazole. The remainder of the detected radioactivity was again to R 33 277 abne. 

No evidence for transformation of azaconazole in the sludge system could be detected the radio-HPLC data suggested that azaconazole was not transformed by the sludge, the elimination of was negligible, and GLC-determinations... 

To a solution of perillyl alcohol (34, 91,2 mg, 0.6 mmol) in anhyd CHCl, (0.5 mL) was added a solution of TCHIj (9 mCi, 0.23 mmol) in CDClj (0.5 mL) and stirred for 5 min. 1 M i-BujAI in toluene (2mL) was added and the mixture stirred at rt for 3 h. The reaction was quenched by the addition of CHClj (5 mL) followed by excess NaF and HjO (2 mL). The CHCl, layer was separated, dried and evaporated to give the product for NMR and radio-HPLC analyses. HPLC purification afforded 3 mCi of the cyclopropane derivative which represents a radiochemical yield of 33%. 

Such phenomena dictated two major philosophies for our work with pyrethroids (a) a mass balance approach was taken to account for all losses in the experiments (b) as long as the pyrethroids maintained their chemical integrity (did not hydrolyse or otherwise degrade) then use of radiolabelled analytes was desirable. This allowed the low concentrations of the pyrethroids in the aqueous phase to be accurately and reproducibly determined and the mass balance to be computed. The chemical integrity of the radiochemicals was determined by radio-chromatographic techniques (radio-TLC and radio-HPLC). 

HPLC Instrumentation. The schematic diagram of a radio-HPLC system can be seen in Fig. 9.1.2.1. 

The Sample Application Unit. In the case of radio-HPLC, the more useful system is the injector valve with a sample loop of desired volume, allowing safe filling of the Tc sample. 

Tritium labelled compounds can also be used as true tracers for following the rates of homogeneous reactions. Thus, in the reaction of amines with epoxides, one can label the amine and by taking samples at fixed time intervals, quenching and subjecting them to radio-HPLC one can follow the disappearance of amine, the increase in the formation of a 1 1 complex and in some cases, the appearance of further complexes until reaction is complete (Fig. With so much information becoming available it is... 

Fig. 2. (A) Scheme for the reaction of phenylglycidyl ether (PGE) and [G- H]aniline. (B) Radio-HPLC separation of primary amine and adducts for the reaction between PGE and aniline at various stages and (C) Variation in radiojictivity (counts s ) for the reactions (A) decrease in [G- H]aniline concentration, (V) appearance of the 1 1 complex and (+) formation of the 2 1 complex. Reproduced with permission.

Figure 4. Radio-HPLC chromatograms showing accumulation of CoA esters from [U- C]hexadecanoyl-CoA by rat heart mitochondria in the presence of (A) 0,(C) 2mM potassium maleate. Rat heart mitochondria were incubated with 90 xM [U- Clhexadecanoyl-CoA and CoA esters analysed by radio HPLC. The chromatograms are representative of 3-S incubations. Peak identification 1, TCA cycle intermediates, 2, acetyl- 3, dec-2-enoyl- 4, 3-hydroxydodecanoyl- 5, decanoyl- 6, dodec-2-enoyl- 7, 3-hydroxytetradecanoyl- ...

---