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[A modified FEP (free erythrocyte protoporphyrin) test (author's transl)]
Abstract:
In order to simplify FEP (free erythrocyte protoporphyrin) test, we studied on the Piomelli's method, specially on the preparation of standard solution and on the role of celite-saline. N,N-dimethylformamide (DMFA) was used as the solvent of protoporphyrin standard (protoporphyrin IX dimethylester, Sigma Chemical Co.). The stock solution was stable for over 6 months at 4 degrees C. To examine the recovery and extraction efficiency, the stock solution (PP) diluted with DMFA was also added to blood. Ten microliter of DMFA added to 40 microliter blood had no effect on the FEP extraction. In the absence or at low concentrations of protein components, fluorescence intensity of added protoporphyrin extremely decreased in the extract with celite-saline. It seems to be due to the adsorption of protoporphyrin to celite. In the presence of proteins, there was no difference between fluorescence intensity of protoporphyrin with celite-saline dilution extraction and that with distilled water dilution extraction. The FEP levels in 128 lead workers (blood lead levels, 4.9-80.8 micrograms/100 g) with celite-saline extraction were almost the same as with distilled water dilution extraction. Thus celite-saline dilution was able to be displaced by the distilled water dilution, and the extraction procedure was slightly simplified. With our method, the average recovery was 93% and extraction efficiency was 80-90%.
Insights
Simplifying the free erythrocyte protoporphyrin (FEP) test, this study found that distilled water can replace celite-saline in extraction. This modification simplifies the procedure without affecting FEP levels in lead workers.
Area of Science:
- Biochemistry
- Analytical Chemistry
- Toxicology
Context:
- The free erythrocyte protoporphyrin (FEP) test is crucial for monitoring lead exposure.
- Current methods, like Piomelli's, involve complex extraction steps.
- Optimizing these methods is essential for routine clinical application.
Purpose:
- To simplify the FEP test by evaluating the role of celite-saline in protoporphyrin extraction.
- To assess the stability of protoporphyrin standard solutions.
- To determine the efficiency and recovery rates of the optimized extraction method.
Summary:
- N,N-dimethylformamide (DMFA) proved a stable solvent for protoporphyrin IX dimethylester standard solutions.
- Celite-saline extraction showed decreased fluorescence in low-protein samples due to adsorption, unlike distilled water extraction.
- Replacing celite-saline with distilled water in extraction yielded comparable FEP levels in lead workers, simplifying the procedure.
Impact:
- The study simplifies the FEP testing protocol, making it more accessible for clinical laboratories.
- The optimized method achieves high average recovery (93%) and extraction efficiency (80-90%).
- This simplification can lead to more widespread and efficient monitoring of lead exposure.