Determination of Low Levels of Perchlorate in Lettuce and Spinach Using Ion Chromatography−Electrospray Ionization Mass Spectrometry (IC-ESI-MS)

2006 ◽  
Vol 54 (6) ◽  
pp. 2012-2017 ◽  
Author(s):  
Angelia L. Seyfferth ◽  
David R. Parker
Keyword(s):  
Mass Spectrometry ◽  
Electrospray Ionization ◽  
Ion Chromatography ◽  
Electrospray Ionization Mass Spectrometry ◽  
Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Esi Ms ◽  
Low Levels

scholarly journals DETERMINATION OF PESTICIDES IN WATER BY LIQUID CHROMATOGRAPHY-(ELECTROSPRAY IONIZATION)-MASS SPECTROMETRY (LC-ESI-MS)

2004 ◽  
Vol 14 ◽  
Author(s):  
SONIA C. N. QUEIROZ ◽  
KAREL LAZOU ◽  
PAT SANDRA ◽  
ISABEL C. S. F. JARDIM
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Ground Water ◽  
Electrospray Ionization ◽  
Electrospray Ionization Mass Spectrometry ◽  
Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Esi Ms ◽  
Pesticides In Water

Desenvolveu-se método para a determinação de selecionado grupo de pesticidas em água (de torneira e subterrânea), usando cromatografia em fase líquida (ionização do tipo electrospray) espectrometria de massas (CL-IE-EM). Os pesticidas dimetoato, carbaril, simazina, atrazina, ametrina, tebutiuron, diuron e linuron foram isolados por meio de extração líquidolíquido com diclorometano e analisados em coluna de fase reversa, tipo C-18, com eluição por gradiente e vazão de 1 mL min-1. Foram obtidas recuperações nas faixas de 89% a 112% (R.S.D. ≤ 10%) para água de torneira e de 76 a 98% (R.S.D. ≤ 6%) para água subterrânea. O procedimento de enriquecimento, que pré-concentra amostras em 500 vezes, seguido do uso de monitoramento seletivo de íon (modo SIM) forneceu limite de quantificação suficientemente baixo para atender a legislação internacional (0,1 µg.L-1). O método desenvolvido mostrou-se prático, eficiente e confiável para a determinação dos pesticidas selecionados em amostras de água. DETERMINAÇÃO DE PESTICIDAS EM ÁGUA POR CROMATOGRAFIA EM FASE LÍQUIDA (IONIZAÇÃO DO TIPO ELECTROSPRAY)-ESPECTROMETRIA DE MASSAS (CL-IE-EM) Abstract A method for determination of a selected group of pesticides in water (tap and ground water) was developed using liquid chromatography-(electrospray ionization)-mass spectrometry (LC-ESI-MS). The pesticides dimethoate, carbaryl, simazine, atrazine, ametryne, tebuthiuron, diuron and linuron were isolated using liquid-liquid extraction with dichloromethane and analyzed on a reversed phase column, C-18, with gradient elution at flow rate of 1 mL. min-1. Recoveries ranged from 89% to 112% (R.S.D. ≤ 10%) for tap water and from 76% to 98% (R.S.D ≤ 6%) for ground water. The enrichment procedure, followed by use of the selected ion monitoring (SIM) mode gave quantification limits low enough to reach the international legislation level of 0.1 µg.L-1, with a 500-fold preconcentration. The method developed is practical, efficient and reliable for the determination of the selected group of pesticides in the water samples.

scholarly journals De Novo Structural Determination of the Oligosaccharide Structure of Hemocyanins from Molluscs

Biomolecules ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1470
Author(s):  
Pavlina Dolashka ◽  
Asya Daskalova ◽  
Aleksandar Dolashki ◽  
Wolfgang Voelter
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Electrospray Ionization ◽  
Electrospray Ionization Mass Spectrometry ◽  
Physiological Role ◽  
Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Esi Ms ◽  
Carbohydrate Epitopes

A number of studies have shown that glycosylation of proteins plays diverse functions in the lives of organisms, has crucial biological and physiological roles in pathogen–host interactions, and is involved in a large number of biological events in the immune system, and in virus and bacteria recognition. The large amount of scientific interest in glycoproteins of molluscan hemocyanins is due not only to their complex quaternary structures, but also to the great diversity of their oligosaccharide structures with a high carbohydrate content (2–9%). This great variety is due to their specific monosaccharide composition and different side chain composition. The determination of glycans and glycopeptides was performed with the most commonly used methods for the analysis of biomolecules, including peptides and proteins, including Matrix Assisted Laser Desorption/Ionisation–Time of Flight (MALDI-TOF-TOF), Liquid Chromatography - Electrospray Ionization-Mass Spectrometry (LC/ESI-MS), Liquid Chromatography (LC-Q-trap-MS/MS) or Nano- Electrospray Ionization-Mass Spectrometry (nano-ESI-MS) and others. The molluscan hemocyanins have complex carbohydrate structures with predominant N-linked glycans. Of interest are identified structures with methylated hexoses and xyloses arranged at different positions in the carbohydrate moieties of molluscan hemocyanins. Novel acidic glycan structures with specific glycosylation positions, e.g., hemocyanins that enable a deeper insight into the glycosylation process, were observed in Rapana venosa, Helix lucorum, and Haliotis tuberculata. Recent studies demonstrate that glycosylation plays a crucial physiological role in the immunostimulatory and therapeutic effect of glycoproteins. The remarkable diversity of hemocyanin glycan content is an important feature of their immune function and provides a new concept in the antibody–antigen interaction through clustered carbohydrate epitopes.

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