Comparison of NCS solubilization and a wet combustion technique for 14C measurement in dried biological tissues
✍ Scribed by Larry Wheeler; A. Strother
- Publisher
- Elsevier Science
- Year
- 1973
- Tongue
- English
- Weight
- 386 KB
- Volume
- 53
- Category
- Article
- ISSN
- 0003-2697
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✦ Synopsis
Two techniques, NCS solubilization and wet combustion, were found to be equal in their ability to measure the "C present in various dried rat tissues. Larger tissue samples with higher efficiencies were possible with wet combustion but it was inadequate for ring-labeled FClcarbaryl; it also requires constant supervision by personnel in addition to being very time consuming. NCS solubilization is much more rapid and capable of quantitative recoveries of ring-and carbonyl-labeled carbaryl. NCS seems to be a more rapid alternative when sufficient "C is present in tissue for analysis.
Carbaryl, 1-naphthyl N-methylcarbamate, is a pesticide of the cholinesterase inhibitor type. In studying the disposition of 14C-labeled carbaryl in various fetal and maternal tissues of pregnant rats, a rapid and efficient method of determining 14C concentrations in tissues was needed. Ring and carbonyl 14C-labeled carbaryl were used in the study.
Several techniques for tissue solubilization and 14C determination were tried. These included: solubilization with alcoholic NaOH (1) or KOH (2)) aqueous homogenates with phase solubilizers (3)) and/or suspending in thixotropic gel's (1, 4). These methods resulted in poor digestion, loss of 14C activity, and prolonged and excessively high chemiluminescence that limited their usefulness. This communication compares the results of solubilizing with NCS and a wet combustion technique to determine if there is any significant difference between the two methods.
A modification of Jeffay's (5) ethanolamine technique was used with a Van Slyke wet combustion reagent (6, 7). Good recoveries resulted with the carbonyl-labeled carbaryl but the Van Slyke wet combustion reagent apparently was not capable of fully oxidizing the ring-labeled carbaryl to "COZ. The wet combustion procedure proved to be extremely time consuming compared to the solubilization technique when analyzing a large number of samples. A much less extensive comparison between 42