液相色谱/离子阱质谱和飞行时间质谱分析橄榄油中的特丁津除草剂

本文摘要介绍了液相色谱／离子阱质谱和液相／飞行时间质谱对橄榄油中特丁津的定性定量分析．详细介绍了样品处理,包括液-液萃取和以氨基硅胶为基质分散的固相萃取法．样品的净化采用Florisil硅土小柱,用乙腈洗脱溶质．液相色谱／离子阱质谱的MS／MS模式采集特征离子m／z174．而利用液相／飞行时间质谱进行精确质量数分析（[M＋H]^＋,m／z230）,同时得到碎片的精确质量数和特征同位素分布．对于飞行时间质谱测得的质量精度小于ppm．此方法具有高灵敏度、线性好及精度高的优点．液相／离子阱质谱和飞行时间质谱可以作为橄榄油中特丁津的常规方法．[编者按]     

A comprehensive evaluation of two sample treatment procedures for the determination of emerging and historical halogenated flame retardants in biota

Environmental Science and Pollution Research - Two different sample preparation protocols for the determination of 37 emerging and historical halogenated flame retardants (HFRs) in marine tissues...     

Solid-phase extraction followed by liquid chromatography-time-of-flight-mass spectrometry to evaluate pharmaceuticals in effluents. A pilot monitoring study

The present work provides a multi-residue analytical method for determining a selection of 20 pharmaceuticals from diverse therapeutical classes in hospital effluent wastewater. The method is based on the simultaneous extraction of the target compounds by solid phase extraction (SPE), followed by liquid chromatography-time-of-flight-mass spectrometry (LC-TOF-MS) analysis. Using TOF-MS, accurate mass measurements within 2 ppm error were obtained for most of the pharmaceuticals studied. Empirical formula information can be obtained by this method, allowing the unequivocal identification of the target compounds in the samples. Validation studies showed that LC-TOF-MS analysis is a valuable new tool for identification and quantification of pharmaceuticals in wastewater. Recoveries, using Oasis HLB cartridges at pH 7, were higher than 75% for all pharmaceuticals, except for ranitidine, 4-methylaminoantipyrine (4-MAA), cefotaxime and omeprazole, which needed specific pH conditions for their extraction. Linearity of response over two orders of magnitude was demonstrated (r > 0.99). Matrix effects resulting in suppression of the response were observed. For most of the compounds ion suppression was less than 39%, except for metronidazole, carbamazepine 10,11-epoxide, naproxen and erythromycin, where the signal suppression was 42%, 59%, 46% and 95%, respectively. A simple and effective approach to minimize or avoid matrix interferences was the 1 : 4 dilution of the SPE extracts. Method detection limits (MDLs) and quantification limits (MQLs) ranged between 4-115 ng l(-1) and 14-384 ng l(-1), respectively. The precision of the method, calculated as relative standard deviation (RSD), ranged from 1.1-19.8% and 1.7-21.7% for intra- and inter-day, respectively. The developed analytical method was applied to the analysis of hospital effluent wastewater during a survey study. 18 of the 20 pharmaceuticals studied were detected at concentration levels of microg l(-1), reaching in some cases concentrations over 100 microg l(-1), and in the case of the analgesic and antipyretic dipyrone metabolite, higher than 1000 microg l(-1).     

Dimer formation during UV photolysis of diclofenac

Dimer formation was observed during ultraviolet (UV) photolysis of the anti-inflammatory drug diclofenac, and confirmed with mass spectrometry, NMR and fluorescence analysis. The dimers were combinations of the two parent molecules or of the parent and the product of photolysis, and had visible color. Radical formation during UV exposure and dissolved oxygen photosensitized reactions played a role in dimer formation. Singlet oxygen formed via photosensitization by photolysis products of diclofenac. It reacted with diclofenac to form an epoxide which is an intermediate in some dimer formation pathways. Quantum yield of photolysis for diclofenac was 0.21 ± 0.02 and 0.19 ± 0.02 for UV irradiation from medium pressure and low pressure mercury vapor lamps, respectively. Band pass filter experiments revealed that the quantum yield is constant at wavelengths >200 nm. The same dimers formed in laboratory grade water when either of the two UV sources was used. Dimers did not form in wastewater effluent matrix, and diclofenac epoxide molecules may have formed bonds with organic matter rather than each other Implications for the importance of dimer formation in NOM are discussed.     

液相飞行时间质谱(LC/MSD TOF)和液相色谱/离子阱质谱(LC/MSD Trap)测定色拉蔬菜中的氯烟碱类杀虫剂

本工作考察了液相色谱／飞行时间质谱检测器(LC／MSDTOF)和液相／离子阱质谱检测器(LC／MSD Trap)联用技术分析一些氯烟碱类杀虫剂的可行性．杀虫剂包括：啶虫咪(acetamiprid)，吡虫啉(imidacloprid)和噻虫啉(thiacloprid)．色拉蔬菜有四种：番茄、辣椒、莴苣和黄瓜．本文介绍的内容包括三种氯烟碱类杀虫剂的LC／MSDTOF和LC／MSD Trap质谱，TOF获得的实验分子式和四种蔬菜基质中氯烟碱类杀虫剂的MS／MS碎片离子．同时也将详细介绍样品制备程序以及色拉蔬菜中杀虫剂的回收、最低检测限(MDL)的质谱质量、线性，使用TOF和Trap对纯溶剂和四种蔬菜提取物中杀虫剂的定量分析．给出了来自市场的实际色拉蔬菜样品中杀虫剂的分析结果．