An electrospray ionization tandem mass spectrometry (ESI-MS/MS) system with an online dual-loop cleanup device was developed for simultaneous quantitation of the urinary benzene exposure biomarkers trans,trans-muconic acid (ttMA) and S-phenylmercapturic acid (SPMA). The cleanup device was constructed from an autosampler, two electrically operated two-position switching valves, a reversed-phase C18 trap cartridge, a 200-microL loop, and two solvent-delivery pumps. The device was interfaced directly with a triple-quadrupole mass spectrometer and fully controlled by computer software and hardware. Because isotope dilution by introducing 13C-labeled ttMA and SPMA as internal standards was employed, the precision of the analytical system was high (for ttMA, intra- and inter-day CV values ranged from 3.82-4.53%; for SPMA, 2.13-7.06%). The calibration curves obtained using human urine spiked with ttMA were linear from 15.6-4000 microg/L (R = 0.9998) and SPMA at concentrations from 0.78-200 microg/L (R = 0.9993). The method detection limit (MDL) for SPMA was 0.23 microg/L. The MDL of ttMA could not be determined accurately because of unavailability of an appropriate blank urine matrix, but was estimated to be lower than 7.43 microg/L. Without tedious manual sample cleanup procedures the analytical system is fully automated and is therefore useful for high-throughput simultaneous determination of urinary ttMA and SPMA. The sample throughput is roughly 100 samples per day. With the selectivity and the sensitivity provided by MS/MS detection, the analytical system can be used for large-scale monitoring of environmental or occupational exposure of humans to benzene.
Biosynthesis of peanut stilbenes, including resveratrol as the secondary metabolites, could be enhanced by subjecting the kernels to germination and wound-stress. Investigations of the bio-elicited peanut sprout powder (BPSP) addressed on characterization of the comprising stilbenes and effectiveness in longevity extension deserves intensive research. In this study, peanut kernels were subjected to germination and wound-stress in preparation of BPSP. The methanol extracts of BPSP were medium pressure liquid chromatographic (MPLC) fractionated and semi-preparative HPLC recovered and followed by instrumental identification and biological activity determinations of the isolated stilbenes. In longevity experiments, 16 female 11-mon-old BALB/c mice and both genders of 12-mon-old ICR mice were daily fed with BPSPsupplemented diets at doses of 0, 0.1 and 0.5 g BPSP/kg bw for 750 and 762 days, respectively. Based on chemical characterization, enriched quantity of stilbenes in the BPSP up to ca. 1%
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