High-performance liquid chromatographic determination of urinary trans, trans-muconic acid excreted by workers occupationally exposed to benzene.

Objective: To investigate the relationship between trans, trans-muconic acid (ttMA) as benzene metabolite of occupational workers and benzene concentration in air.

Methods: A rapid and sensitive high-performance liquid chromatography was developed to determine the level of urinary ttMA. ttMA was extrated from urinary samples in liquid-liquid phase a ODS (2) (5u) column (phi 4.6 mm x 150 mm) and detected at wavelength 264 nm in a UV detector using vanillic acid as an internal standard. The mobile phase was acetaticacid/tetrahydrofuran/methanol/water (v/v, 1:2:10:87). The method was validated with 56 urine samples collected from occupationally benzene-exposed individuals.

Results: A correlation coefficient (r = 0.9963) was found for ttMA ranging 0.10-10.00 microg/mL. The limit of detection was 0.10 microg/mL. The recovery and reproducibility were generally over 90%. There was a positive correlation between ttMA and benzene level in air. The equation was Y = 0.859 + 0.108C (before work, r = 0.6200) or Y = 1.980 + 0.179C (after work, r = 0.7930).

Conclusion: This method can be used to determine and control the level of urinary ttMA in those who are occupationally exposed to benzene.