The Assessment of Liver Reserve Function by Spectrophotometry based on Determination of Phenacetin and Paracetamol.

Background: To establish a technical system for assessing liver reserve function based on spectrophotometry by detection of phenacetin and paracetamol in blood samples.

Methods: Taking detected contents of phenacetin and paracetamol by high performance liquid chromatography (HPLC) as standard, which was proved to be able to detect drug concentrations with high resolution and accuracy, we established a technical system based on the spectrophotometric technique to assay phenacetin and paracetamol, including the color system, the maximum absorption wavelength, the influence factors of color system, and the optimal conditions for hydrolysis. Then we verified our established system compared with that under HPLC by recovery test.

Results: This study established a technical system to detect phenacetin and paracetamol in blood samples using spectrophotometry. Mainly, 3 mol/L hydrochloric acid (HCl) was added to samples for hydrolysis for 30 minutes, then, adding 0.02% 1,2-naphthoquinone-4-sulfonate (NQS), 1% cetyltrimethyl ammonium bromide (CTA) and 2% sodium hydroxide (or 3% sodium carbonate) (ratio of 1:6:1:2 or 3), and the absorbance was measured at 500 nm and 570 nm to calculate their concentrations.

Conclusions: Using an established spectrophotometric system to detect phenacetin and paracetamol in blood samples could assess liver reserve function, which was proved comparable with HPLC in resolution and repeatability.