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02/11 - Determinazione dellacido S-fenilmercapturico mediante cromatografia liquida accoppiata a spettrometria di massa con trappola ionica. Cinzia La Rocca, Luigi Turrio Baldassarri, Maria Luisa Casella 2002, ii, 63 p.
S-phenylmercapturic acid determination through liquid chromatography and mass spectrometry with ion trap.
Cinzia La Rocca, Luigi Turrio Baldassarri, Maria Luisa Casella
2002, ii, 63 p. Rapporti ISTISAN 02/11 (in Italian)
An analytical method was set up to determine S-phenylmercapturic acid (S-PMA), a benzene urinary metabolite and a specific biomarker. The method is based on HPLC-MS/MS with an electrospray interface and an ion trap analyzer. The separation of the analyte is performed on a pre-treated urine extract by a reversed-phase C18 column; a linear gradient elution is used, whilst the determination is carried out on the daughter ion obtained by fragmentation (MS/MS) of the isolated (M+1)+ ion, in the positive-ion polarity. The (M+1)+, is formed by S-PMA protonation. This study was first set up on S-PMA standard solutions and then tested on a real urine sample of a non professionally exposed subject. The instrumental analytical method developed in this study for the S-phenylmercapturic acid is characterized by a good precision (coefficient of variation= 4.57% in 5 replicated injections), a satisfactory accuracy (an estimated 6.46%) and a high sensitivity (10 pg of injected analyte); it allows determination of the benzene urinary metabolite even at the low levels occurring in environmental exposures. The method sensitivity is comparable to spectrofluorimetric detectors, although these need one derivatization step, and it is better than gas chromatographic- mass spectrometric methods, which also need derivatization.
Key words: Benzene, S-Phenylmercapturic acid (S-PMA), Metabolite, Biomarker of exposure, HPLC-MS/MS, Electrospray, Ion trap
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