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This paper describes the synthesis and characterization of a new molecularly imprinted solid-phase microextraction fiber able to renew its selective binding sites because of the gradual thermal decomposition of the polymeric network. The injector of the chromatograph operates at 300 °C, and during the desorption step of the analytes (in a short period), the polymeric network is degraded from the surface to the core in volatile compounds that do not interfere with the analysis. The renewable MIP fiber was successfully employed to extract triazole fungicides (triadimenol, tebuconazole, and metconazole) from grape juice samples followed by gas chromatography mass spectrometry analysis. The method was adjusted to the quadratic models from 100 to 2000 μg L(-1), with good precision and accuracy. The limits of quantification (100 μg L(-1) for all analytes) were sufficient to analyze triadimenol, tebuconazole, and metconazole in grape juice samples, where their maximum residue limits in Brazil are 100, 2000, and 1000 μg L(-1), respectively.

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Recebido em 4/1/12; aceito em 17/4/12; publicado na web em 20/7/2012 MOLECULARLY IMPRINTED SOLID-PHASE EXTRACTION OF URINARY TRANS-TRANS MUCONIC ACID AND ANALYSIS BY GAS CHROMATOGRAPHY-MASS SPECTROMETRY. This paper describes selective molecularly imprinted solid-phase extraction of ttMA from urine samples followed by derivatization and analysis by gas chromatography/mass spectrometry (GC/MS). The analytical calibration curve ranged from 0.3 to 7.0 mg L-1 (r = 0.999) and the limit of quantitation (LOQ) was 0.3 mg L-1. The method was applied for the determination of ttMA in urine samples from smokers and concentrations detected ranged from < LOQ to 1.64 mg L-1. Thus, the proposed method proved adequate for the determination of urinary ttMA in the biomonitoring of occupational exposure to low levels of benzene.