Search

A sensitive and reliable liquid chromatographic-tandem mass spectrometric method for enantiomeric determination of five chiral azole antifungals (econazole, ketoconazole, miconazole, tebuconazole, and propiconazole) in wastewater and sludge has been established and validated. An isotope-labeled internal standard was used for quantification. Recovery of the individual enantiomers was usually in the range of 77-102 % for wastewater and 71-95 % for sludge, with relative standard deviations within 20 %. No significant difference (p>0.05) was observed between recovery of pairs of enantiomers of the chiral azole antifungals except for those of tebuconazole. Method quantification limits for individual enantiomers were 0.3-10 ng L(-1) and 3-29 ng g(-1) dry weight for wastewater and sludge, respectively. The method was used to investigate the enantiomeric composition of the azole pharmaceuticals in wastewater and sludge samples from a sewage treatment plant in China. Enantiomers of miconazole, ketoconazole, and econazole were widely detected. The results showed that the azole antifungals in wastewater and sludge were generally racemic or marginally non-racemic. The method is a useful tool for investigation of the enantiomeric occurrence, behavior, and fate of the chiral azole antifungals in the environment.

A sensitive method has been developed and validated for the determination of diverse groups of pharmaceuticals, steroid hormones, and hormone-like personal care products in sewage sludge. Samples were extracted by ultrasonic-assisted extraction followed by solid-phase extraction cleanup. For determination of estrogens and hormone-like phenolic compounds, sample extracts were further derivatized with dansyl chloride and purified with silica gel column chromatography to improve the analytical sensitivity. The chemicals were determined by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) in multiple-reaction monitoring mode. Recoveries ranged mostly from 63% to 119% with relative standard deviations within 15%. Method quantification limits were 0.1-3 ng g(-1) dry weight (dw) for sewage sludge. The method was applied to a preliminary investigation of pharmaceuticals and personal care products (PPCPs) in sewage sludge and sediment in the Pearl River Delta, South China. Triclosan, triclocarban, 2-phenylphenol, bisphenol A, and parabens were ubiquitously detected at 3.6-5088.2 ng g(-1) dw in sludge and 0.29-113.1 ng g(-1) dw in sediment samples, respectively. Estrone, carbamazepine, metoprolol, and propranolol were also frequently quantified in the sludge and sediment samples. The dewatering process caused no significant losses of these PPCPs in sewage sludge.

Sensitive and reliable methods have been developed and validated for determination of commonly consumed azole antifungal pharmaceuticals (clotrimazole, econazole, ketoconazole, and miconazole) and biocides (propiconazole and tebuconazole) in various waters and sewage sludge. Solid phase extraction (SPE) combined with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was used to determine the azole antifungals in waters. Azole antifungals in sewage sludge were extracted with ultrasonic-assisted extraction, followed by SPE cleanup and UHPLC-MS/MS detection. Quantification was performed by internal standard calibration in multiple reaction monitoring mode. Recoveries were mostly in the range of 52-110% with relative standard deviations generally within 20%. Method quantification limits were 0.5-6 ng L(-1) in waters and 3-9 ng g(-1) dry weight (dw) in sewage sludge, respectively. The methods were applied to determine the azole antifungals in wastewater, river water, sediment, and sewage sludge sampled from the Pearl River Delta, China. Clotrimazole, ketoconazole, and miconazole were widely detected at low ng L(-1) in waters, low ng g(-1) dw in river sediment, and low microg g(-1) dw in sewage sludge. The methods can provide valuable tools for investigating occurrence and fate of the azole antifungals in the environment., (2010 Elsevier B.V. All rights reserved.)

Abstract: A specific polyclonal anti-norfloxacin antibody was obtained, and a sensitive indirect competitive enzyme-linked immunosorbent assay (icELISA) was developed for determining trace amounts of norfloxacin in various waters. Good linearity was achieved in the range from 0.1 to 10μgL−1. The average IC50 value was determined to be 2.2μgL−1 and the limit of detection was 0.016μgL−1 at a signal-to-noise ratio of 3 in phosphate-buffered saline buffer. Recoveries of norfloxacin at various spiking levels ranged from 74 to 105% in groundwater, surface water, treated and untreated wastewater samples, with relative standard deviations of 3–5%. The assay was applied for determining norfloxacin in municipal wastewater, surface water, and groundwater collected in a metropolis of China. Raw wastewater samples were only submitted to filtration and pH adjustment while the other water samples were pre-concentrated by solid phase extraction prior to the icELISA assay. Good agreement of the results obtained by the icELISA and liquid chromatography tandem mass spectrometry further confirmed the reliability and accuracy of the icELISA for rapid detection of norfloxacin in waters. [Copyright &y& Elsevier]

Dechlorination reactions of organochlorines can commonly take place in fragmentation on electron ionization mass spectrometry (EI-MS) and collision-induced dissociation (CID) on electron ionization tandem mass spectrometry (EI-MS/MS), possibly accompanied with chlorine isotope effects. However, it remains unclear whether characteristics of chlorine isotope effects of individual organochlorines occurring on different types of mass spectrometers are similar or different. Revelation of characteristics of chlorine isotope effects on different mass spectrometers may help to elucidate mechanisms of dechlorination reactions and fragmental pathways of organochlorines. This study investigated the characteristics of chlorine isotope effects of two model organochlorines, i.e., tetrachloroethylene and trichloroethylene, during fragmentation/CID on EI-double focusing magnetic-sector high resolution MS (EI-HRMS), EI-quadrupole MS (EI-qMS) and EI-triple-quadrupole MS/MS (EI-MS/MS) that were all coupled with gas chromatography (GC). The patterns of chlorine isotope ratios measured by different instruments were different, showing different characteristics of chlorine isotope effects. On EI-HRMS, both normal and inverse chlorine isotope effects were observed; while on EI-qMS, only normal isotope effects were found, and on EI-MS/MS merely inverse isotope effects were discovered. On EI-HRMS and EI-qMS, inter-ion and intra-ion chlorine kinetic isotope effects (Cl-KIEs) might participate in isotope fractionation processes and contribute to inverse inter-ion and normal intra-ion isotope effects, respectively, and the dominant isotope effects determined the direction of observed (apparent) isotope effects. On EI-MS/MS, both inter-ion and intra-ion Cl-KIEs were inverse at high collision energies (including 30 and 45 eV) and contributed to normal inter-ion and inverse intra-ion isotope effects, respectively, and the inverse intra-ion isotope effects were the dominant, leading to the inverse apparent isotope effects in all dechlorination reactions. Particularly, the chlorine isotope ratios measured by EI-qMS exponentially decreased with the increasing Cl atoms of ions, implying that the intra-ion isotope effects rose as broken C–Cl bonds increased. Moreover, fundamentals of chlorine isotope effects in the stepwise multibond dechlorination reactions were revealed with the aid of density functional theory calculations. The different measurement timescales and geometries of the mass spectrometers and the difference in EI-induced fragmentation and CID might result in the different characteristics of chlorine isotope effects. This study may be conducive to elucidating isotope fractionation behaviors and fragmental pathways of organochlorines on EI-MS(/MS), and provides new insights into the mechanisms of dechlorination reactions losing multiple chlorine atoms. Image 1 • Chlorine isotope effects of 2 organochlorines on 3 types of EI-MS were investigated. • Stepwise dechlorination reactions led to varied Cl isotope effects on each EI-MS. • Different characteristics of Cl isotope effects on the 3 types of EI-MS were found. • Different timescales, geometries and fragmental modes might cause the characteristics. • Inter-ion and intra-ion Cl-KIEs essentially determined the observed isotope effects. [ABSTRACT FROM AUTHOR]