Assuntos
Análise de Alimentos , Nitrofuranos/análise , Nitrofuranos/metabolismo , Animais , Cromatografia Líquida de Alta Pressão/métodos , Furazolidona/análogos & derivados , Furazolidona/análise , Furazolidona/metabolismo , Humanos , Espectrometria de Massas/métodos , Estrutura Molecular , Nitrofurantoína/análogos & derivados , Nitrofurantoína/análise , Nitrofurantoína/metabolismo , Nitrofurazona/análogos & derivados , Nitrofurazona/análise , Nitrofurazona/metabolismoRESUMO
A new method for the determination of peroxyacetic acid (PAA) in gas phase samples is described. It is based on the oxidation of ABTS (2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulfonate) by PAA with formation of a radical cation which is characterized by four strong absorption maxima between 405 nm and 810 nm. These allow for sensitive spectrophotometric determination of the peracid. The selectivity of the method towards hydrogen peroxide is strongly dependent on the sampling method used. Impinger sampling and sampling based on the use of coated solid sorbents (test tubes) was performed. Limits of detection are 10(-8) mol, limits of quantification are 5 x 10(-8) mol, the linear range consists of 1.5 concentration decades in both cases. Using ABTS-coated test tubes above 1 x 10(-7) mol, direct reading of the results is possible and may be used as rapid screening method for the PAA concentration.
Assuntos
Poluentes Atmosféricos/análise , Ácido Peracético/análise , Espectrofotometria/métodos , Poluentes Atmosféricos/toxicidade , Benzotiazóis , Calibragem , Radicais Livres , Ácido Peracético/toxicidade , Peróxidos/análise , Peróxidos/toxicidade , Ácidos Sulfônicos/metabolismoRESUMO
The first selective HPLC methods for the determination of peroxyacetic acid (PAA) in gas phase samples have been developed. PAA reacts with 2-([3-{2-[4-amino-2-(methylsulfanyl)phenyl]- 1-diazenyl}phenyl]sulfonyl)-1-ethanol (ADS) to form the corresponding sulfoxide. Sampling may be performed in impingers using aqueous solutions of the reagent or by test tubes with the reagent coated on a solid sorbent. Sulfide and sulfoxide are separated by means of HPLC and detected at a wavelength of 410 nm. The method is highly selective for PAA in the presence of hydrogen peroxide when sampling in impingers. A 10,000-fold excess of hydrogen peroxide leads to the same peak area compared to PAA. Limit of detection is 10(-8) mol PAA, thus corresponding to PAA concentration of 46 ppb when using a sampling time of 10 min with a flow-rate at 500 ml/min. Another sulfide reagent, methyl-p-tolyl sulfide (MTS) has been used in a similar way with impinger sampling. Major advantages of ADS towards MTS are improved UV-Vis spectroscopic properties and reduced volatility.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Gases/química , Ácido Peracético/análise , Sulfetos/química , Indicadores e Reagentes/química , Espectrofotometria UltravioletaRESUMO
The first instrumental method for simultaneous determination of peroxyacetic acid (PAA) and hydrogen peroxide has been developed. The successive quantitative reaction of PAA with methyl p-tolyl sulfide (MTS) and hydrogen peroxide with triphenylphosphine (TPP) yields the corresponding sulfoxide MTSO and phosphine oxide TPPO. The reagents and their oxides are separated by HPLC on reversed-phase columns with acetonitrile/water gradient elution within 5 min. External calibration with the solid standards of MTSO and TPPO leads to a very accurate and reliable method. Samples are stable and can be stored after derivatization for several days prior to analysis. Real samples from brewery disinfection were analyzed in comparison to titration with excellent correlation.
