Determination of 1-hydroxypyrene in human urine by HPLC with electrochemical detection at a boron-doped diamond film electrode.

A high-performance liquid chromatographic method with electrochemical detection (HPLC-ED) at a boron-doped diamond film electrode with preliminary separation and preconcentration by solid-phase extraction (SPE) has been developed for the determination of 1-hydroxypyrene (1-HP) in human urine. 1-HP is among the most widely used biomarkers of exposure to polycyclic aromatic hydrocarbons. Optimal HPLC-ED conditions have been found: mobile phase methanol-0.05 mol L(-1) phosphate buffer pH 5.0 (80:20, v/v), detection potential +1,000 mV versus Ag/AgCl (3 mol L(-1) KCl), and flow rate 0.8 mL min(-1). For SPE, LiChrolut(®) RP-18 E cartridges were used. The extraction yield was (87.0 ± 5.8)% (n = 5). The concentration dependence of 1-HP was measured in the concentration range from 0.01 to 10 µmol L(-1) (2.18-2,180 µg L(-1)) using methanolic solutions resulting from the SPE pretreatment of spiked human urine samples. The limit of detection (signal-to-noise ratio 3) and the limit of quantification (signal-to-noise ratio 10) of the biomarker were 0.013 µmol L(-1) (2.84 µg L(-1)) and 0.043 µmol L(-1) (9.39 µg L(-1)), respectively, which is sufficient for its determination in the urine of persons exposed to polycyclic aromatic hydrocarbons.

The use of silver solid amalgam electrodes for voltammetric and amperometric determination of nitrated polyaromatic compounds used as markers of incomplete combustion.

Genotoxic nitrated polycyclic aromatic hydrocarbons (NPAHs) are formed during incomplete combustion processes by reaction of polycyclic aromatic hydrocarbons (PAHs) with atmospheric nitrogen oxides. 1-Nitropyrene, 2-nitrofluorene, and 3-nitrofluoranthene as the dominating substances are used as markers of NPAHs formation by these processes. In the presented study, voltammetric properties and quantification of these compounds and of 5-nitroquinoline (as a representative of environmentally important genotoxic heterocyclic compounds) have been investigated using a mercury meniscus modified silver solid amalgam electrode (m-AgSAE), which represent a nontoxic alternative to traditional mercury electrodes. Linear calibration curves over three orders of magnitude and limits of determination mostly in the 10(-7) mol L(-1) concentration range were obtained using direct current and differential pulse voltammetry. Further, satisfactory HPLC separation of studied analytes in fifteen minutes was achieved using 0.01 mol L(-1) phosphate buffer, pH 7.0 : methanol (15 : 85, v/v) mobile phase, and C(18) reversed stationary phase. Limits of detection of around 1 · 10(-5) mol L(-1) were achieved using amperometric detection at m-AgSAE in wall-jet arrangement for all studied analytes. Practical applicability of this technique was demonstrated on the determination of 1-nitropyrene, 2-nitrofluorene, 3-nitrofluoranthene, and 5-nitroquinoline in drinking water after their preliminary separation and preconcentration using solid phase extraction with the limits of detection around 1 · 10(-6) mol L(-1).