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2815683 
Technical Report 
Quantitative Determination of Porphobilinogen and Porphyrins in Urine and Porphyrins in Faeces and Erythrocytes 
Rimington, C 
1971 
NIOSH/00130046 
Broadsheet 70 
1-9 
Methods were developed for the determination of porphobilinogen (487901) and porphyrins in urine, feces, and erythrocytes. Porphobilinogen was determined after condensation with p-dimethylamino-benzaldehyde in acid solution and by measuring absorbance at 552 nanometers. Urine was diluted with water and absorbance was used to calculate porphobilinogen content, in the range of 1 to 10 micrograms per milliliter. Interfering substances were not a problem because of the quantity of porphobilinogen excreted in intermittent porphyria. Coproporphyrin (27121717) and coproporphyprinogens in urine were extracted with ether, coproporphyrinogens were oxidized to porphyrin with iodine, and total uroporhyprin was determined spectrophotometrically as above. Impurities were corrected for by subtracting absorbance at 430 and 380 nanometers from the maximum absorbance at 401 nanometers which was used for calculation. Urinary uroporphyrin (26316369) was determined on that portion of the sample remaining after ether extraction by extracting with cyclohexanone, then acidifying and determining absorbance spectrophotometrically at 3 wavelengths as above. Fecal coproporphyrin and protoporphyrin (553128) were ether extracted, oxidized, acidified and extracted with acetic-acid prior to spectrophotometric determination. Coproporphyrin and protoporphyrin in erythrocytes were extracted with ethyl-acetate and acetic-acid prior to spectrophotometric determination. The author draws no conclusions.