Abstract:Electrospray ionization mass spectrometry (ESI-MS) is being increasingly employed in the study of metal-ligand equilibria in aqueous solution. In the present work, the ESI-MS spectral changes due to different settings of the following instrumental parameters are analyzed: the solution flow rate (F(S)), the nebulizer gas flow rate (F(G)), the sprayer potential (E), and the temperature of the entrance capillary (T). Twenty-eight spectra were obtained for each of six samples containing aluminum(III) and 2,3-dihyd… Show more
“…Although electrospray ionization mass spectrometry (ESI‐MS) is very often employed in the study of metal/ligand equilibria in aqueous solution,1 it is well known that ESI‐MS spectra do not exactly represent the speciation picture of the solution ‘before the measurement’, due to perturbations occurring after the sample injection in the ion source and before the ion detection 1–8. In our previous work,9 these perturbations were correlated with the ESI‐MS spectral changes produced by different settings of some instrumental parameters. We concluded that these correlations allow identification of the perturbations occurring when metal‐ligand solutions are studied by ESI‐MS.…”
Electrospray ionization mass spectrometry (ESI-MS) is very often employed to study metal/ligand equilibria in aqueous solution. However, the ionization process can introduce perturbations which affect the speciation results in an unpredictable way. It is necessary to identify these perturbations in order to correctly interpret the ESI-MS speciation results. Aluminium(III)/1,6-dimethyl-4-hydroxy-3-pyridinecarboxylate (DQ716) aqueous solutions at various pH were analysed by ESI-MS, and speciation results were compared with those obtained by equilibrium techniques. Differences observed were both qualitative and quantitative. The ESI-MS spectral changes due to different settings of the following instrumental parameters were analyzed: the solution flow rate (F(S)), the nebulizer gas flow rate (F(G)), the potential applied at the entrance capillary (E(C)), and the temperature of the drying gas (T(G)). The effects produced by F(S) and E(C) on the spectra strongly suggest the key role of surface activity in determining the relative fraction of the ions reaching the detector. The experimental effects of F(S) and T(G) were interpreted considering the presence of at least two reactions in the gas phase and a dimerization occurring in the droplets. These perturbations cannot be generalized because they appear to be chemical system-related and instrument-dependent. Therefore, the identification of perturbations is a required task for any metal-ligand equilibrium study performed by ESI-MS. Our results indicate that perturbations can be identified by evaluating the effects produced in the spectra by a change of instrumental parameters.
“…Although electrospray ionization mass spectrometry (ESI‐MS) is very often employed in the study of metal/ligand equilibria in aqueous solution,1 it is well known that ESI‐MS spectra do not exactly represent the speciation picture of the solution ‘before the measurement’, due to perturbations occurring after the sample injection in the ion source and before the ion detection 1–8. In our previous work,9 these perturbations were correlated with the ESI‐MS spectral changes produced by different settings of some instrumental parameters. We concluded that these correlations allow identification of the perturbations occurring when metal‐ligand solutions are studied by ESI‐MS.…”
Electrospray ionization mass spectrometry (ESI-MS) is very often employed to study metal/ligand equilibria in aqueous solution. However, the ionization process can introduce perturbations which affect the speciation results in an unpredictable way. It is necessary to identify these perturbations in order to correctly interpret the ESI-MS speciation results. Aluminium(III)/1,6-dimethyl-4-hydroxy-3-pyridinecarboxylate (DQ716) aqueous solutions at various pH were analysed by ESI-MS, and speciation results were compared with those obtained by equilibrium techniques. Differences observed were both qualitative and quantitative. The ESI-MS spectral changes due to different settings of the following instrumental parameters were analyzed: the solution flow rate (F(S)), the nebulizer gas flow rate (F(G)), the potential applied at the entrance capillary (E(C)), and the temperature of the drying gas (T(G)). The effects produced by F(S) and E(C) on the spectra strongly suggest the key role of surface activity in determining the relative fraction of the ions reaching the detector. The experimental effects of F(S) and T(G) were interpreted considering the presence of at least two reactions in the gas phase and a dimerization occurring in the droplets. These perturbations cannot be generalized because they appear to be chemical system-related and instrument-dependent. Therefore, the identification of perturbations is a required task for any metal-ligand equilibrium study performed by ESI-MS. Our results indicate that perturbations can be identified by evaluating the effects produced in the spectra by a change of instrumental parameters.
“…Пертурбације у раствору се дешавају у капљици [12,119] у току њеног испаравања. Испаравање капљице мења концентрацију растворене врсте и сходно томе проузрокује равнотежне помераје у зависности од pH, концентрације, Т и промена јонске јачине.…”
“…Међусобни однос релативне заступљености (релативни интезитет) i 763 /i 719 је сличан односу i 370 /i 326 , што указује на сличне константе комплексирања за L и L-CO 2 врсте [111,119].…”
Section: проучавање комплексирања алуминијума и флероксацина еSi мS сunclassified
“…Изучаване су варијације спектара са променом pH вредности за Аl/L однос, обрачуном релативих интензитиета сигнала слободног лиганда, Аl:L=1:1 и Аl:L=1:2 и награђених комплекса. У ту сврху је израчунат интензитет јона сваког пика у спектру [118,119]. Нађена је сума свих интензитета јона у датом спектру и извршено је дељење јона који се односе на исти тип комплекса сумом свих јона.…”
Section: квантитативна специјација у растворима алуминијум(Iii)-jона unclassified
“…Сходно литератури [119] у идеалним условима R EQUIl =R ESI-MS . Разлике које се јављају су последица ЕSI пертурбација у раствору (разлика у саставу растварача и јонске јачине) Пертурбације се могу десити осим у раствору, на граници фаза течно-гас и у гасној фази.…”
Section: квантитативна специјација у растворима алуминијум(Iii)-jона unclassified
Испитивање реакција хидролизе и комплексирања у растворима алуминијум(III)-јона и неких флуорохинолона методом елект роспреј-тандем масене спектрометрије
Докторска дисертацијаКрагујевац 2013.
Electrospray ionization
(ESI) is an atomization and ionization method through which a solution‐phase analyte can be transferred via minute charged droplets into the gas‐phase as an ion. The first part of this two‐part review on electrospray mass spectrometry considers the formation of these minute charged droplets. Atomization of liquids can take place through mechanical or electrostatic breakup of a liquid jet. In the absence of an electric field, charged droplets of both polarities are formed because of the disruption of the electrical double layer at the air–water interface. Addition of an electric field results in the formation of charged droplets of a single polarity. At sufficiently high electric field strength, mechanical jet disruption is replaced by electrostatic jet disruption giving the highest yield of charged droplets; this is the commonly used conductive DC electrospray. More recent means of forming charged droplets by DC or AC electric fields are discussed in the following sections. Mechanisms for reducing the droplet electrostatic stress such as droplet fragmentation are reviewed in the final section. These processes form the basis for the creation of charged gas‐phase analytes that is described in Current Electrospray Mass Spectrometry: an Overview. Part B. Analyte Charging.
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