Inorganic ion analysis
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Inorganic species still remain of secondary importance when CE is used as an analytical separation tool. Despite considerable efforts of great many groups over last 20 years, plenty of competition, mostly from ion chromatography and elemental MS, restrains the routine use of CE in inorganic analysis. If there is yet hope clinging to make CE a viable alternative in the field, success would ultimately be attained through research activities on negating the disadvantages and amplifying the advantages of the method. Being the latest update of a series of reviews covering the time period from 1990 to 2010, this paper will comment on how and to what extent these challenges of inorganic CE analysis have been addressed in two recent years.
A simple analytical system using disposable, open-tubular ion exchange clean-up precolumns coupled in-line to capillary electrophoresis for direct injection of biological samples is presented. The clean-up precolumns were prepared from fused silica capillaries by thermally initiated layer-by-layer polymerization of poly(butadiene-maleic acid) (PBMA) directly on the capillary wall. Typically, 6 cm long precolumns with 4-layers of PBMA were used for sample pretreatment. A robust and reproducible coupling between the precolumn (75 μm ID) and the analytical capillary (50 μm ID) was achieved using an inexpensive, commercially available low dead volume union. No extra dispersion of the analyte zones was observed. Proteins and other high molecular weight compounds from biological sample matrices were retained on the cation-exchanger sites of the precolumn, which eliminated their adsorption on analytical capillary walls and ensured stable electroosmotic flow and migration times of target analytes. Unretained small inorganic cations migrated freely into the analytical capillary for separation and detection. Applicability of the sample clean-up procedure was proved by determination of major inorganic cations in blood serum and plasma samples using capillary electrophoresis with contactless conductivity detection. Separations were performed in background electrolyte solution consisting of 15 mM L-arginine, 12.5 mM maleic acid, 3 mM 18-crown-6 at pH 5.5 and repeatabilities of migration times and peak areas were below 1.5% and 7.3%, respectively. Less than 1 μL of biological sample was required for injection.
- MeSH
- butadieny chemie MeSH
- chromatografie iontoměničová metody MeSH
- draslík krev izolace a purifikace MeSH
- elektrická vodivost MeSH
- elektroforéza kapilární MeSH
- hořčík krev izolace a purifikace MeSH
- kationty krev chemie izolace a purifikace MeSH
- kovy krev chemie izolace a purifikace MeSH
- lidé MeSH
- maleáty chemie MeSH
- polymery chemie MeSH
- reprodukovatelnost výsledků MeSH
- sodík krev izolace a purifikace MeSH
- vápník krev izolace a purifikace MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
A proof of concept of a novel pervaporation sequential injection (PSI) analysis method for automatic non-chromatographic speciation analysis of inorganic arsenic in complex aqueous samples is presented. The method is based on hydride generation of arsine followed by its on-line pervaporation-based membrane separation and CCD spectrophotometric detection. The concentrations of arsenite (As(III)) and arsenate (As(V)) are determined sequentially in a single sample zone. The leading section of the sample zone merges with a citric acid/citrate buffer solution (pH 4.5) for the selective reduction of As(III) to arsine while the trailing section of the sample zone merges with hydrochloric acid solution to allow the reduction of both As(III) and As(V) to arsine at pH lower than 1. Virtually identical analytical sensitivity is obtained for both As(III) and As(V) at this high acidity. The flow analyzer also accommodates in-line pH detector for monitoring of the acidity throughout the sample zone prior to hydride generation. Under optimal conditions the proposed PSI method is characterized by a limit of detection, linear calibration range and repeatability for As(III) of 22 μg L(-1) (3sblank level criterion), 50-1000 μg L(-1) and 3.0% at the 500 μg L(-1) level and for As(V) of 51 μg L(-1), 100-2000 μg L(-1) and 2.6% at the 500 μg L(-1) level, respectively. The method was validated with mixed As(III)/As(V) standard aqueous solutions and successfully applied to the determination of As(III) and As(V) in river water samples with elevated content of dissolved organic carbon and suspended particulate matter with no prior sample pretreatment. Excellent relative recoveries ranging from 98% to 104% were obtained for both As(III) and As(V).
- MeSH
- arseničnany izolace a purifikace MeSH
- arsenikové přípravky chemie MeSH
- arsenitany izolace a purifikace MeSH
- chemické látky znečišťující vodu izolace a purifikace MeSH
- kalibrace MeSH
- koncentrace vodíkových iontů MeSH
- kyselina citronová chemie MeSH
- limita detekce MeSH
- průtoková injekční analýza metody MeSH
- řeky chemie MeSH
- spektrofotometrie přístrojové vybavení metody MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Basic operation principles of a lightweight, low power, low cost, portable ion chromatograph utilizing open tubular ion chromatography in capillary columns coated with multi-layer polymeric stationary phases are demonstrated. A minimalistic configuration of a portable IC instrument was developed that does not require any chromatographic eluent delivery system, nor sample injection device as it uses gravity-based eluent flow and hydrodynamic sample injection adopted from capillary electrophoresis. As a detection device, an inexpensive commercially available capacitance sensor is used that has been shown to be a suitable substitute for contactless conductivity detection in capillary separation systems. The built-in temperature sensor allows for baseline drift correction typically encountered in conductivity/capacitance measurements without thermostating device. The whole instrument does not require any power supply for its operation, except the detection and data acquisition part that is provided by a USB port of a Netbook computer. It is extremely lightweight, its total weight including the Netbook computer is less than 2.5kg and it can be continuously operated for more than 8h. Several parameters of the instrument, such as detection cell design, eluent delivery systems and data treatment were optimized as well as the composition of eluent for non-suppressed ion chromatographic analysis of common inorganic cations (Na(+), NH(4)(+), K(+), Cs(+), Ca(2+), Mg(2+), transition metals). Low conductivity eluents based on weakly complexing organic acids such as tartaric, oxalic or pyridine-2,6-dicarboxylic acids were used with contactless capacitance detection for simultaneous separation of mono- and divalent cations. Separation of Na(+) and NH(4)(+) cations was optimized by addition of 18-crown-6 to the eluent. The best separation of 6 metal cations commonly present in various environmental samples was accomplished in less than 30min using a 1.75mM pyridine-2,6-dicarboxylic acid and 3mM 18-crown-6 eluent with excellent repeatability (below 2%) and detection limits in the low micromolar range. The analysis of field samples is demonstrated; the concentrations of common inorganic cations in river water, mineral water and snow samples were determined.
Ion-pairing reversed-phase high-performance liquid chromatography (RP-HPLC) operation conditions were studied to obtain information useful for development and optimization of separation methods suitable for HPLC/MS analysis of dyes. The retention of eight sulphonated azodyes with widely differing structures (1-5 acid groups, molecular weight range 350-1220) was measured in mobile phases containing various ion-pairing reagents in aqueous-methanolic mobile phases. The effects of the type and of the concentration of ammonium acetate, tetrabutylammonium hydrogen sulphate and five di- and tri-alkylammonium acetate ion-pairing reagents on the chromatographic behaviour of dyes were compared in mobile phases with varying concentrations of methanol. Structural effects on the retention of dyes were studied in detail. The retention scale based on lipophilic and polar indices can be used for optimization of mobile phase for HPLC/MS of dyes and, on the other hand, may provide some information on the structure of unknown dyes.
The principal focus of this work is the in-depth analysis of the biological efficiency of inorganic calcium-filled bacterial cellulose (BC) based hydrogel scaffolds for their future use in bone tissue engineering/bioengineering. Inorganic calcium was filled in the form of calcium phosphate (β-tri calcium phosphate (β-TCP) and hydroxyapatite (HA)) and calcium carbonate (CaCO₃). The additional calcium, CaCO₃ was incorporated following in vitro bio-mineralization. Cell viability study was performed with the extracts of BC based hydrogel scaffolds: BC-PVP, BC-CMC; BC-PVP-β-TCP/HA, BC-CMC-β-TCP/HA and BC-PVP-β-TCP/HA-CaCO₃, BC-CMC-β-TCP/HA-CaCO₃; respectively. The biocompatibility study was performed with two different cell lines, i.e., human fibroblasts, Lep-3 and mouse bone explant cells. Each hydrogel scaffold has facilitated notable growth and proliferation in presence of these two cell types. Nevertheless, the percentage of DNA strand breaks was higher when cells were treated with BC-CMC based scaffolds i.e., BC-CMC-β-TCP/HA and BC-CMC-β-TCP/HA-CaCO₃. On the other hand, the apoptosis of human fibroblasts, Lep-3 was insignificant in BC-PVP-β-TCP/HA. The scanning electron microscopy confirmed the efficient adhesion and growth of Lep-3 cells throughout the surface of BC-PVP and BC-PVP-β-TCP/HA. Hence, among all inorganic calcium filled hydrogel scaffolds, 'BC-PVP-β-TCP/HA' was recommended as an efficient tissue engineering scaffold which could facilitate the musculoskeletal (i.e., bone tissue) engineering/bioengineering.
- MeSH
- celulosa chemie MeSH
- hydrogely chemie MeSH
- hydroxyapatit chemie MeSH
- kosti a kostní tkáň cytologie MeSH
- lidé MeSH
- myši MeSH
- tkáňové inženýrství metody MeSH
- tkáňové podpůrné struktury chemie MeSH
- vápník chemie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The natural sources of Tl are less bioavailable and hence of less concern in regulation than its anthropogenic sources. Tl is more toxic to mammals than Hg. Cd, Pb, Ag, Cu or Zn and has been responsible for many poisonings. Tl occurs in two oxidation states, Tl(I) and Tl(III), the former being the predominant species in natural environment. In contrast to inorganic compounds, in which the Tl(I) ion is more stable in aqueous solutions than the Tl (III) ion, the latter is more stable in organic compounds. As the Tl concentrations in environmental samples are in the µg kg-1 range or less, it is necessary to use separation and preconcentration techniques, such as coprecipitation. The frequently used methods of Tl fractionation and speciation analysis are extraction, ion exchange and ion chromatography. They are combined with Tl determination using voltammetry, neutron activation analysis, spectrophotometry, mass spectrometry, inductively coupled plasma optical emission spectrometry and electrothermal and hydride-generation AAS.
Bicarbonate and phosphate constitute major salivary buffering components, and their importance consists in the neutralization of acidic gastric contents during reflux episodes. In this work, capillary electrophoresis with capacitively coupled contactless conductivity detector was applied for the analysis of bicarbonate, phosphate, and another inorganic (chloride, nitrite, nitrate, sulfate, thiocyanate) and organic anions (acetate, butyrate) to evaluate their levels in saliva. The background electrolytes of different composition and pH between 6.02-9.41 were assessed for the bicarbonate and phosphate determination by comparison of the real analyses of a model solution with the simulation by PeakMaster software. The optimized background electrolyte was composed of 10 mM 2-(N-morpholino)ethanesulfonic acid, 20 mM arginine, and 30 µM cetyltrimethylammonium bromide, pH 8.95. Using this BGE, the anion levels were compared in saliva from 20 patients suffering from gastroesophageal reflux disease (GERD) and saliva from 12 healthy subjects. Bicarbonate levels were significantly elevated in saliva from GERD patients suggesting the possible applicability of bicarbonate as a biomarker in non-invasive diagnostics of GERD by CE-C4 D.
