The illicit burn practices on farms promote food contamination that is harmful and must be controlled by improved analytical methods. Polycyclic aromatic hydrocarbons (PAHs), which have high toxic ...and carcinogenic potential, can contaminate foods, mainly through fire exposure. Considering the toxicity of PAHs, development of sensitive, simple, and solvent-free methods to analyze PAHs in foods is necessary. This work presents the development of a new method to analyze PAHs in eggs using cold fiber-solid-phase microextraction (CF-SPME) and gas chromatography coupled to mass spectrometry (GC-MS). Parameters of temperature extraction, ultrasonic agitation time, sample mass, and modifiers were evaluated to obtain the best CF-SPME conditions. The new method uses a minimal amount of solvent and showed good linearity in the range of 0.0005 to 5.60 μg/g. Detection limits were from 0.0002 to 0.046 μg/g, and quantification limits were from 0.0005 to 0.152 μg/g. The method was applied to PAHs analysis of chicken egg samples from a farm near a site of an uncontrolled tire fire. The concentrations of PAHs in this study ranged from 0.926 to 1.668 μg/g. All PAHs were detected in the samples. The total toxicity was estimated by benzo(a)pyrene equivalent (BaPeq) and did not decrease significantly in the period (6 weeks) of sample collection.
Novel and quantitative mass spectrometry methods for rapid and accurate enantiomeric excess determination are presented. These methodologies use electrospray ionization (ESI) and mass spectrometry ...(MS) to detect and analyze, via collision-induced dissociation (CID), mass-selected transition metal complexes that promote enantio especific interactions. The data from CID are conveniently treated by the kinetic method, a sensitive linear free energy method of treating mass spectrometric results. Four different variations of this methodology are described: single ratio method (S R), quotient ratio method (Q R), fixed ligand method (S Rfixed), and quotient ratio method with fixed ligand (Q Rfixed). These individual methods are compared and their main features discussed in detail.
A multiresidue method for the quantification of 13 sulfonamides in animal feed is described. It involves the application of a modified QuEChERS procedure followed by HPLC–MS/MS (high performance ...liquid chromatography coupled to tandem mass spectrometry) analysis. The best conditions for the extraction solution and PSA (primary secondary amine) mass were determined. After optimization, the method was validated according to the European Commission Decision 2002/657/EC. The validation levels employed were 25, 50 and 75 μg kg−1. Acceptable values were obtained for the following parameters: linearity (0.9864 < r2 < 0.9993), decision limit (50.4 μg kg−1 < CCα < 55.8 μg kg−1), detection capability (50.7 μg kg−1<CCβ < 55.8 μg kg−1), limit of quantification (0.9 μg kg−1 < LOQ < 7.1 μg kg−1), accuracy (86.0 < recovery rates < 106.8), precision (3.6 < repeatability < 19.5), (5.5 < intermediate precision < 21.6), measurement uncertainty (MU) (4.1 < MU < 32.6) and selectivity. These findings met the Codex requirements, which allow for the routine use of the method by the laboratories linked to the Ministry of Agriculture, Livestock and Food Supply of Brazil. Finally, the method was applied to real samples and only one of them showed positive for sulfamethazine, however, with a concentration below the LOQ of the method.
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A rapid and sensitive method for the determination of the enantiomeric composition of ibuprofen solutions is presented. This approach uses electrospray ionization tandem mass ...spectrometry and applies the kinetic method to perform the data analysis. Deviations of ca. 1.5% between the actual and experimental enantiomeric composition were observed. The simplicity, sensitivity, and precision of the method make it potentially suitable for the quantification of ibuprofen enantiomers in biological samples.
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