Direct measurement of the glucuronide conjugate of 1-hydroxypyrene in human urine by using liquid chromatography with tandem mass spectrometry

Abstract

To evaluate human exposure to polycyclic aromatic hydrocarbons (PAHs), we developed a rapid, simple and sensitive method for determining 1-hydroxypyrene-glucuronide (1-OHP-G) in human urine. To improve precision, a deuterated glucuronide was used as an internal standard. The method requires only 1 mL of urine. The urine was treated with a mixed-mode anion-exchange and reversed-phase solid-phase extraction cartridge (Oasis MAX). The analytes were analyzed with a C 18 reversed-phase column with a gradient elution, followed by tandem mass spectrometry with electrospray ionization in negative ion mode. The detection limit of 1-OHP-G (corresponding to a signal-to-noise ratio of 3) was 0.13 fmol/injection. Urinary concentrations of 1-OHP-G determined by this method were strongly correlated (r 2 =0.961) with concentrations of 1-hydroxypyrene by conventional HPLC with fluorescence detection.

Polymer‐coated Boron Doped Diamond Optically Transparent Electrodes for Spectroelectrochemical Sensors

“…It can be seen that at a scan rate of 25 mV/s~E p % 200 mV and when increased to 100 mV/s,~E p % 335 mV. This is indicative of the resistivity of the BDD OTE, which was found to be 120 W using an Ohms law plot obtained from the cyclic voltammetry data shown in Figure 3A using Equation (1) where R is the ohmic resistance (both solution and electrode resistance) [35][36].…”

“…The potentiostat was a BASi Epsilon Electrochemical Analyzer (Bioanalytical Systems, West Lafayette, IN). The extrapolated baseline current method described by Kissinger and Heineman was used to measure peak currents (i p ) [35][36]. Indium tin oxide (ITO) coated glass slides (Corning 1737F and 7059, 11-50 W/sq, 130 nm thick on 1.1 mm glass, Thin Film Devices, Anaheim, CA) with dimensions of 10 40 mm were used to compare with results obtained on BDD.…”

“…Increase in electrode resistivity has the negative implication of significant iR drop that distorts the electrochemical signal. Slow electron transfer and iR drop can cause significant increases in~E p for cyclic voltammetry (CV) measurements, which leads to peak broadening and/or distortion [35][36] .…”

Quantification of Glucuronide Metabolites in Biological Matrices by LC-MS/MS

“…If endogenous glucuronides are present in "blank" samples , like for instance steroid glucuronides, then it is necessary to spike the blanks with labeled glucuronides for matrix effect and recovery calculation (Pozo, Van Eenoo et al 2008). The glucuronides can be retained to various extents on a reversed phase (Trontelj, Bogataj et al 2007), on a strong anion-exchange (Pu, McKinney et al 2004), on a mixed-mode (Kakimoto, Toriba et al 2008) and even on strong and weak cation exchange sorbents (Okura, Komiyama et al 2007), depending on the ionization and lipophilic properties of the aglycone. Even highly polar glucuronides and sulfates, like paracetamol conjugates can have a high recovery on mixed-mode weak anion exchange sorbents like Waters Oasis WAX (Sunkara and Wells 2010).…”

Fast and simple method for the determination of urinary 1‐hydroxypyrene

“…On the other hand, it requires a sample treatment before injection in the analytical system. Moreover, this method uses an expensive deuterium-labeled internal standard (1-OH-Pyd 9 -G) [14].…”