Feasibility of urinary trans, trans-muconic acid determination using high performance liquid chromatography for biological monitoring of benzene exposure.

Benzene is an important carcinogenic substance used in many industrial processes. Inhalation of this substance can cause both acute and chronic toxicity. In this study, monitoring of benzene exposure by high-performance liquid chromatography (HPLC) for urine trans, trans-muconic acid (ttMA) determination was adapted. We described a new adapted sensitive and specific HPLC method. We mixed 0.5 mL of urine sample with 2 mL of Tris Buffer containing vanillic acid as internal standard (IS) and percolate this through a preconditioned ion-exchange column. After rinsing the column with phosphoric acid solution, acetate buffer, and deionized water, we eluated the analytes with 2 mL of an equivolume solution of 1.5 mol/L sodium chloride and methanol. Of this, 10 microliter was injected into the HPLC column. The mobile phase consisted of, per liter, 10 ml of acetic acid, 100 ml of methanol, and 5 mmol/L sodium acetate. The flow rate was started at 1.2 ml/min. The ttMA and IS were detected at 4.2 to 4.4 and 12.6-13.3 minutes, respectively. The lowest detection limit was 0.05 mg/L.