title: Reducing the effect of chemiluminescence on the efficiency of extracting 14C-neomycin from fortified kidney tissue as measured by a liquid scintillation system.
abstract: Extraction efficiency was monitored, using 14C-neomycin and liquid scintillation counting, during development of a procedure to isolate neomycin from fortified kidney tissue. Chemiluminescence caused 119% false positive recovery at 0.16 ppm neomycin (1260 disintegrations/min (dpm) activity). However, the contribution of chemiluminescence to false positive recovery was negligible above 8 ppm neomycin (63,000 dpm activity). To reduce chemiluminescence, fortified kidney tissue was extracted with saline by homogenization, mixed with Protosol at 70 degrees C for 1 h, cooled 5 min at 4 degrees C and neutralized with acetic acid. The digest was mixed with Aquasol and incubated 1 h at 47 degrees C, followed by equilibration for 2 h in the counter. The procedure allows reliable monitoring of extraction efficiency down to about 407 dpm activity from 14C-neomycin (0.05 ppm) with maximum chemiluminescence of about 4%.
mesh_terms: D000818:Animals; D002250:Carbon Radioisotopes; D007668:Kidney / Q000032:analysis*; D008163:Luminescent Measurements; D009355:Neomycin / Q000302:isolation & purification*; D012588:Scintillation Counting / Q000379:methods; D012995:Solubility
chemical_list: D002250:Carbon Radioisotopes; D009355:Neomycin