Skip to content. Skip to navigation
Sections
Personal tools
You are here: Home
Featured Journal
Navigation
Site Search
 
Search only the current folder (and sub-folders)
Log in


Forgot your password?
New user?
Check out our New Publishers' Select for Free Articles
Journal Search

Analytical and Bioanalytical Chemistry (v.379, #5-6)

Spectroscopy Challenge 7 by Silvia Paasch; Reiner Salzer (pp. 741-745).
Solution to chemical logic by Janis Bisenieks; Juris Meija (pp. 746-747).

Rapid automated assay of anti-oxidation/radical-scavenging activity of natural substances by sequential injection technique (SIA) using spectrophotometric detection by Miroslav Polášek; Petr Skála; Lubomír Opletal; Luděk Jahodář (pp. 754-758).
A PC-controlled sequential injection analysis (SIA) system equipped with a spectrophotometric diode-array detector is used for rapid monitoring and evaluation of antioxidation/radical scavenging activity of biological samples. The automated method is based on the known reaction of stable 2,2′-diphenyl-1-picrylhydrazyl radical (DPPH) with antioxidants in organic or aqueous-organic media resulting in bleaching of DPPH due to its “quenching” by the interaction with the analytes. The decrease of the absorbance of DPPH (compared to blank experiment carried out with water–ethanol 1:1 instead of the test solution) measured at 525 nm is related to concentration of an antioxidant in the test solution. With the optimised SIA procedure it is possible to detect down to micromolar concentrations of model antioxidants such as ascorbic acid, caffeic acid, (+)-catechin, (−)-epicatechin and rutin and to evaluate the concentration of these antioxidants in the micromolar to millimolar range. The sample throughput is 45 h−1. Thanks to its rapidity and sensitivity, the proposed SIA method is suitable for performing routine screening tests for the presence of various antioxidants in large series of lyophilised herbal or mushroom extracts (the amount of sample needed for the analysis is several milligrams).

Keywords: Sequential injection analysis (SIA); Assay of antioxidants; Diphenylpicrylhydrazyl radical (DPPH); Plant extracts


Rapid spectrofluorimetric determination of lisinopril in pharmaceutical tablets using sequential injection analysis by Constantinos K. Zacharis; Paraskevas D. Tzanavaras; Demetrius G. Themelis; Georgios A. Theodoridis; Anastasios Economou; Pantelis G. Rigas (pp. 759-763).
The present work reports for the first time a simple and rapid method for the spectrofluorimetric determination of lisinopril (LSP) in pharmaceutical formulations using sequential injection analysis (SIA). The method is based on reaction of LSP with o-phthalaldehyde (OPA) in the presence of 2-mercaptoethanol (borate buffer medium, pH=10.6). The emission of the derivative is monitored at 455 nm upon excitation at 346 nm. The various chemical and physical conditions that affected the reaction were studied. The calibration curve was linear in the range 0.3–10.0 mg L−1 LSP, at a sampling rate of 60 injections h−1. Consumption of OPA reagent was significantly reduced compared with conventional flow injection (FI) systems, because only 50 μL of OPA was consumed per run. The method was found to be adequately precise (s r=2% at 5 mg L−1 LSP, n=10) and the 3σ detection limit was 0.1 mg L−1. The method was successfully applied to the analysis of two pharmaceutical formulations containing LSP. The results obtained were in good agreement with those obtained by use of high-performance liquid chromatography (HPLC), because the mean relative error, e r, was <1.8%.

Keywords: Lisinopril; Sequential injection; Spectrofluorimetry; o-Phthalaldehyde; Pharmaceutical formulations


Time-based on-line preconcentration cold vapour generation procedure for ultra-trace mercury determination with inductively coupled plasma atomic emission spectrometry by Aristidis N. Anthemidis; George A. Zachariadis; Christos E. Michos; John A. Stratis (pp. 764-769).
A time-based sequential dispensing on-line column preconcentration procedure for mercury determination at trace levels by cold vapour generation inductively coupled plasma atomic emission spectrometry (CV-ICP-AES), by means of a unified module of a preconcentration column and a gas–liquid separator (PCGLS) is described. The complex of mercury formed on-line with ammonium pyrrolidine dithiocarbamate (APDC) is retained on the surface of the hydrophobic poly(tetrafluoroethylene) (PTFE) turnings, which are packed into the lower compartment of the PCGLS. Subsequently, mercury vapour is generated directly on the PTFE turnings by reductant SnCl2 and separated from the liquid mixture via the PCGLS by argon purge gas. The outlet of the PCGLS is connected directly to the torch adapter of the plasma without the normal spray chamber and nebulizer. With 60-s preconcentration time and 12.0 mL min−1 sample flow rate, the sampling frequency is 30 h−1. The calibration curve is linear over the concentration range 0.02–5.0 μg L−1, the detection limit (c L) is 0.01 μg L−1 and the relative standard deviation (s r) is 3.1% at the 1.0 μg L−1 level. The proposed method was evaluated by analysis of BCR CRM 278 (Mytilus Edulis) reference material and applied to the determination of total mercury in digested urine, blood and hair samples.

Keywords: Mercury; Solid-phase extraction; Dithiocarbamate; On-line; Cold vapour; Inductively coupled plasma


Separation of organoselenium compounds and their electrochemical detection by Maria Th. Ochsenkühn-Petropoulou; Fotios N. Tsopelas (pp. 770-776).
A simplified procedure based on ion-exchange separation of selenourea (Se-U) and selenocystamine (Se-CM), which have very close half-wave potential when they are simultaneously analyzed by voltammetric techniques, has been developed and optimized. Thus, selenocystamine remains in the cation exchanger Purolite C 100 H, whereas selenourea is found in the effluent and is determined by square wave cathodic stripping voltammetry using Na2CO3 as electrolyte. Selenocystamine is then eluted from the cation exchanger using 4 M HCl and analyzed by square wave cathodic stripping voltammetry in the HCl solution. For each voltammetric determination the corresponding parameters were investigated and optimized; the obtained detection limits were 0.3 ng Se mL−1 for Se-CM and 2 ng Se mL−1 for Se-U. A flow sheet for the separation of inorganic (Se(IV) and Se(VI)) and organoselenium compounds (Se-U, Se-CM, (CH3)2Se2, and (CH3)2Se) developed for their electrochemical detection is presented and it was successfully applied to a certified reference material, an environmental soil sample, and a urine sample.

Keywords: Selenourea; Selenocystamine; Ion-exchange separation; Voltammetry; Organoselenium compounds; Urine


Dialysis-Chelex method for determination of exchangeable copper in human plasma by Tony I. Venelinov; Ian M. Davies; John H. Beattie (pp. 777-780).
A method based on dialysis in the presence of histidine, and subsequent copper adsorption and preconcentration using Chelex-100 resin, has been developed for selective extraction of exchangeable copper from blood plasma. The method was verified by comparative analysis using two different instrumental techniques, ICP–MS and AAS. The results obtained were in excellent agreement. Accurate quantification of the exchangeable copper and the firmly bound copper was achieved. The method was further validated by analysis of a lyophilised human serum certified reference material.

Keywords: Exchangeable copper; Dialysis; Chelex-100; ICP–MS


HPLC determination of estradiol, its degradation product, and preservatives in new topical formulation Estrogel HBF by Lucie Nováková; Petr Solich; Ludmila Matysová; Jan Šícha (pp. 781-787).
This paper deals with the development of a novel method for simultaneous determination of estradiol, its degradation product estrone, and two preservatives, methylparaben and propylparaben, in the topical preparation Estradiol HBF. After optimization of the analytical conditions the method was validated and applied in studies of the stability of the topical preparation Estrogel HBF. Separation of all these compounds was performed on a Supelco Discovery C18 (250 mm×3.0 mm, 5 μm) analytical column. A mixture of acetonitrile, methanol, and water (23:24:53 v/v) was chosen as mobile phase. UV absorbance at 225 nm was used for detection and quantitation of analytes. The total analysis time was less than 12 min at a flow rate of 0.9 mL min−1. All the compounds were isolated from the topical gel by simple extraction with an acetonitrile solution of hydrocortisone, as internal standard, and using sonication and centrifugation thereafter. The supernatant was injected directly on to the analytical column. The recovery of the procedure was from 96.9 to 100.4%. Validation of method according international guidelines was successfully performed.

Keywords: HPLC; Estradiol; Methylparaben; Propylparaben; Degradation product; Estrone; Validation


Structural and optical characterization of pyrolytic carbon derived from novolac resin by S. Theodoropoulou; D. Papadimitriou; L. Zoumpoulakis; J. Simitzis (pp. 788-791).
The structural and optical properties of technologically interesting pyrolytic carbons formed from cured novolac resin and cured novolac/biomass composites were studied by X-Ray Diffraction Analysis (XRD), and Fourier Transform Infrared (FTIR), Raman and Photoluminescence (PL) spectroscopy. Pyrolysis of the cured materials took place at temperatures in the range 400–1000 °C. The most important weight loss, shrinkage and structural changes of pyrolyzed composites are observed at temperatures up to 600 °C due to the olive stone component. In the same temperature range, the changes in pyrolyzed novolac are smaller. The spectroscopic analysis shows that novolac pyrolyzed up to 900 °C has less defects and disorder than the composites. However, above 900 °C, pyrolyzed novolac becomes more disordered compared to the pyrolyzed composites. It is concluded that partial replacement of novolac by olive stone in the composite materials leads to the formation of a low cost, good quality product.

Keywords: Pyrolytic carbon; XRD; FTIR; Raman; PL


Superconducting coatings of MgB2 prepared by electrophoretic deposition by Maria T. Ochsenkühn-Petropoulou; Alexandros F. Altzoumailis; Rachel Argyropoulou; Klaus-Michael Ochsenkühn (pp. 792-795).
The electrophoretic deposition technique was applied for the production of MgB2 superconducting coatings on various substrates, by using a suspension of MgB2 superconducting powder in an organic solvent. The main parameters that affect the deposition rate of the process and the quality of the coatings produced, such as the initial concentration of the suspension, the applied voltage and the distance between the electrodes, were investigated and optimized. The coatings produced were characterized and investigated for possible interaction between the substrate and the deposited superconductor by X-ray diffraction. The superconducting properties were measured by magnetic susceptibility (superconducting quantum interference device).

Keywords: MgB2 ; Superconducting coatings; Electrophoretic deposition; Commercial substrates; X-ray diffraction


Investigation of the separation of scandium and rare earth elements from red mud by use of reversed-phase HPLC by Lambrini V. Tsakanika; Maria Th. Ochsenkühn-Petropoulou; Leonidas N. Mendrinos (pp. 796-802).
A chromatographic method has been developed for separation and determination of scandium (Sc) and rare earth elements (REEs) in samples from a red mud (RM)-utilization process. Reversed-phase high-performance liquid chromatography (RP-HPLC) with post-column derivatization using 4-(2-pyridylazo)-resorcinol (PAR) and UV–visible detection at 520 nm was tested using different gradient elution profiles and pH values to optimize separation and recovery, primarily for Sc but also for yttrium and the individual lanthanides, from iron present in the samples. The separation was performed in less than 20 min by use of a mobile phase gradient. The concentration of α-hydroxyisobutyric acid (α-HIBA), as eluent, was altered from 0.06 to 0.4 mol L–1 (pH 3.7) and 0.01 mol L–1 sodium salt n-octane sulfonic acid (OS) was used as modifier. Very low detection limits in the nanogram range and a good resolution for Sc and REEs except for Y/Dy were achieved. Before application of the method to the red mud samples and to the corresponding bauxites, Sc and REEs were leached from red mud with 0.6 mol L–1 HNO3 and mostly separated, as a group, from the main elements by ion exchange/selective elution (6 mol L–1 HNO3) in accordance with a pilot-plant process developed in this laboratory. After evaporation of the eluent to dryness the extracted elements were re-dissolved in the mobile phase. By use of this chromatographic method Sc, which is the most expensive of the elements investigated and occurs in economically interesting concentrations in red mud, could be separated not only from co-existing Fe but also from Y/Dy, Yb, Er, Ho, Gd, Eu, Sm, Nd, Pr, Ce and La. All the elements investigated were individually recovered. Their recoveries were found to be nearly quantitative.

Keywords: Rare earth elements; Separation by reversed-phase high-performance liquid chromatography; Red mud; Scandium


Simultaneous determination of chlorophyll a and chlorophyll b by derivative spectrophotometry by Emel Ergun; Birsen Demirata; Gulcin Gumus; Reşat Apak (pp. 803-811).
Chlorophyll a (Chl a) and chlorophyll b (Chl b) plant pigments, which are important in the food industry and are beneficial as environmental pollution indicators, have been extracted with a novel solvent mixture (1:1 v/v acetone–propanol) not containing chloroform and simultaneously determined by first-derivative spectrophotometry. The results were statistically compared to those obtained by the ordinary absorption spectrophotometric reference utilizing the principle of additivity of absorbances. The testing of the developed method in synthetic mixtures of Chl a and Chl b and in real plant material samples (grass, spinach, chard, purslane, black cabbage, crisp lettuce, rocket, dill and seaweed) proved successful in that the developed extractive derivative spectrophotometric method was both rapid and precise, and was not dependent on the Chl a/b ratio in contrast to the reference method which was adversely affected by the latter parameter.

Keywords: Chlorophyll a; Chlorophyll b; Extraction; Simultaneous determination; Derivative spectrophotometry


SPME analysis of volatile compounds from unfermented olives subjected to thermal treatment by T. Navarro; C. de Lorenzo; R. A. Pérez (pp. 812-817).
The effect of different types of thermal treatment, designed to increase the product’s shelf-life, on the volatile composition of “Campo Real” unfermented table olives, has been studied by headspace solid-phase microextraction (HS-SPME) and GC–MS analysis. Different SPME fibres were evaluated to determine their selectivity for a mixture of the main components of the different spices used in “Campo Real” olive dressing. Of the different fibres investigated, the polydimethylsiloxane/divinylbenzene (PDMS/DVB) fibre was selected for analysis of the olive brines, which contained nine main aroma components. The types of thermal treatment were sterilisation (121 °C, 15 min) and four pasteurisation conditions (60 °C or 80 °C each for 5 or 9 min). Pasteurisation did not lead to significant changes in the amounts of these nine volatile compounds; the 2-butanol signal was reduced by treatment at 80 °C. On the other hand, sterilisation of the brine resulted in an decrease in the signals from these compounds and the appearance of a new, high signal for benzaldehyde; the origin of this has not yet been determined. Results suggest that the selected pasteurisation conditions do not significantly modify the typical, and valued, aroma characteristics of “Campo Real”.

Keywords: Solid-phase microextraction; Volatile compounds; Table olives; Pasteurisation; Spices


Chemometric procedure for the study of fractionated wastewater ingredients using RP-HPLC/diode array spectrophotometer by M. E. Kotti; A. G. Vlessidis; N. P. Evmiridis (pp. 818-824).
A fast screening method of domestic wastewater is reported based on fractionation with RP-HPLC and diode array absorption detection implemented by chemometric treatment of the spectra using cluster analysis, deconvolution, simulation, and multiple regression statistical techniques. The proposed method is limited to constituents that absorb in the UV-Vis region which include most of the toxic organic pollutants.

Keywords: Domestic wastewater; Fast screening; RP-HPLC/DAAD detection; Chemometric treatment


Standardless PIXE analysis of thick biomineral structures by E. A. Preoteasa; Rodica Georgescu; C. Ciortea; Daniela Fluerasu; Livia Harangus; Andreea Iordan; Feride Severcan; Handan Boyar; Elena Preoteasa; I. Piticu; D. Pantelica; Vl Gheordunescu (pp. 825-841).
The particle-induced X-ray emission (PIXE) of thick biomineral targets provides pertinent surface analysis, but if good reference materials are missing then complementary approaches are required to handle the matrix effects. This is illustrated by our results from qualitative and semiquantitative analysis of biomaterials and calcified tissues in which PIXE usually detected up to 20 elements with Z > 14 per sample, many at trace levels. Relative concentrations allow the classification of dental composites according to the mean Z and by multivariate statistics. In femur bones from streptozotocin-induced diabetic rats, trace element changes showed high individual variability but correlated to each other, and multivariate statistics improved discrimination of abnormal pathology. Changes on the in vitro demineralization of dental enamel suggested that a dissolution of Ca compounds in the outermost layer results in the uncovering of deeper layers containing higher trace element levels. Thus, in spite of significant limitations, standardless PIXE analysis of thick biomineral samples together with proper additional procedures can provide relevant information in biomedical research.

Keywords: PIXE; Trace elements; Biomaterials; Dental enamel; Bone; Multivariate statistics


Solid-phase microextraction–capillary gas chromatography combined with microwave-induced plasma atomic-emission spectrometry for selenite determination by Emmanouil Dimitrakakis; Christina Haberhauer-Troyer; Yo Abe; Maria Ochsenkühn-Petropoulou; Erwin Rosenberg (pp. 842-848).
The use of solid-phase microextraction (SPME) with gas chromatography coupled to microwave-induced plasma atomic-emission detection (GC–MIP-AED) is described for selenite [Se(IV)] speciation. Aqueous standards were derivatised with sodium tetraethyl- or tetrapropylborate and extracted by SPME. Headspace extraction of the ethyl and propyl derivatives was studied. Relevant experimental conditions were optimised, including conditions for derivatisation and extraction and those of gas chromatographic analysis. The limits of detection achieved for headspace sampling of derivatised Se(IV) were in the low ng mL−1 range for both ethylation and propylation. When the method was applied to analysis of selenite in selenised yeast reference material results were in good agreement with the indicated values.

Keywords: Selenium; SPME; Sodium tetraethylborate; Sodium tetrapropylborate; Gas chromatography; Microwave-induced plasma


Analysis of bioactive ingredients in the brown alga Fucus vesiculosus by capillary electrophoresis and neutron activation analysis by Kalle Truus; Merike Vaher; Mihkel Koel; Andres Mähar; Imants Taure (pp. 849-852).
Two different types of bioactive components of the seaweed Fucus vesiculosus were analysed: (1) polyphenols (phlorotannins) by capillary electrophoresis (CE) and (2) mineral part (including bioactive microelements) by neutron activation analysis (NAA). CE experiments were carried out using a UV detector (at 210 nm) and an uncoated silica capillary. The best separation was achieved at a voltage of 20 kV using borate or acetate buffer in a methanol/acetonitrile mixture as background electrolyte. The CE analysis data were confirmed by high-performance liquid chromatography (HPLC). Determination of mineral composition of algal biomass by NAA was performed on the basis of various nuclides; the best results (from 38 elements determined) were obtained for Mn, Fe, Zn, As, Br, Sr, I, Ba, Au and Hg.

Keywords: Fucus vesiculosus; Neutron activation analysis; Mineral composition; Polyphenols; Phlorotannins; Capillary electrophoresis


A highly sensitive and specific enzyme immunoassay for detection of β-amanitin in biological fluids by Ramadan A. Abuknesha; Alexandra Maragkou (pp. 853-860).
Polyclonal antisera to β-amanitin were generated in sheep and used to construct a competitive ELISA for measurement of the toxin in human serum and urine. The assay had a detection limit of about 80 pg mL−1, a dynamic range of 80–2,000 pg mL−1, a cross reactivity of 22% with α-amanitin, and no cross reactivities with cyclic peptides from algal sources. Assay responses in buffer, serum, and urine were remarkably similar. Coupling of the toxin to carrier proteins was carried out by previously unreported methods. The key step that allowed the construction of the highly sensitive assay was the introduction of a novel heterologous hapten derivative made of β-amanitin-cyanuric chloride derivative. The new derivative overcame the problems of bridge binding that was, in this case, particularly serious with the homologous hapten derivative. The study demonstrated that the developed antiserum and ELISA procedure can be used to detect β-amanitin and related toxins from Amanita phalloides in human serum and urine samples from suspected poison cases and enable early treatment to be administered.

Keywords: Amanitins; ELISA; Bridge binding; Homology; Heterology


Speciation of selenium in selenium-enriched shiitake mushroom, Lentinula edodes by Yasumitsu Ogra; Kazuya Ishiwata; Jorge Ruiz Encinar; Ryszard Łobiński; Kazuo T. Suzuki (pp. 861-866).
The major selenium compound in an aqueous extract of the most popular mushroom in Eastern Asian countries, shiitake (Lentinula edodes), fortified with selenium (Se) was identified by means of hyphenated techniques, i.e. HPLC-inductively coupled argon plasma mass spectrometry and HPLC-electrospray ionization mass spectrometry (HPLC–ICP MS and HPLC–ESI MS). Sixty-eight per cent of the total Se in the selenized shiitake was extracted with water, and 49.8% of the Se in the water extract was eluted in the high molecular mass fraction (>40,000 kDa) before incubation at 37 °C. After incubation, 40.6% of the Se in the water extract was eluted in a lower molecular mass fraction and the Se eluted in the high molecular mass fraction had decreased to 14.0%, suggesting that the major selenium compound in the water extract was initially in a form bound to macromolecule(s) and was then enzymatically liberated from the macromolecule(s). The retention time of the liberated selenium compound in HPLC–ICP MS matched that of selenomethionine (SeMet), and the masses of molecular and fragment ions detected by HPLC–ESI MS also suggested that the selenium compound was SeMet. The selenized shiitake accumulated Se as SeMet, and SeMet might be bound to the water extractable high molecular mass protein(s).

Keywords: Selenium; Speciation; Lentinula edodes ; ICP MS; ESI MS; Selenomethionine


Preconcentration of copper, cadmium, and lead with a thiacalix[4]arenetetrasulfonate-loaded Sephadex A-25 anion-exchanger for graphite-furnace atomic-absorption spectrometry by Hiroaki Matsumiya; Nobuhiko Iki; Sotaro Miyano; Masataka Hiraide (pp. 867-871).
A rapid column-adsorption method has been developed for concentrating traces of copper, cadmium, and lead in water prior to their determinations by graphite-furnace atomic-absorption spectrometry. The adsorbent used was prepared by loading a strongly basic anion-exchanger QAE-Sephadex A-25 (50 mg) with thiacalix[4]arenetetrasulfonate (20 μmol). Two-hundredfold preconcentration of the analyte elements was achieved by passing 100 mL of sample solution (pH 8.0) through a column packed with the adsorbent (6 mm i.d.×7 mm high) at a flow rate of 10 mL min−1 and by the subsequent elution with 500 μL of aqueous nitric acid solution (1 mol L−1). The practical applicability of the proposed method was evaluated by analyzing certified reference seawater samples.

Keywords: Preconcentration; Chelating adsorbent; Calixarene; Heavy metals; Atomic-absorption spectrometry; Seawater


Practical and quality-control aspects of multi-element analysis with quadrupole ICP–MS with special attention to urine and whole blood by Jan L. M. de Boer; Rob Ritsema; Sjoerd Piso; Hans van Staden; Wilbert van den Beld (pp. 872-880).
Two screening methods were developed for rapid analysis of a great number of urine and blood samples within the framework of an exposure check of the population after a firework explosion. A total of 56 elements was measured including major elements. Sample preparation consisted of simple dilution. Extensive quality controls were applied including element addition and the use of certified reference materials. Relevant results at levels similar to those found in the literature were obtained for Co, Ni, Cu, Zn, Sr, Cd, Sn, Sb, Ba, Tl, and Pb in urine and for the same elements except Ni, Sn, Sb, and Ba in blood. However, quadrupole ICP–MS has limitations, mainly related to spectral interferences, for the analysis of urine and blood, and these cause higher detection limits. The general aspects discussed in the paper give it wider applicability than just for analysis of blood and urine—it can for example be used in environmental analysis.

Keywords: ICP–MS; Multi-element; Quality control; Urine; Blood


Quantitative analysis of perchlorate in extracts of whole fish homogenates by ion chromatography: comparison of suppressed conductivity detection and electrospray ionization mass spectrometry by Eric D. Dodds; John M. Kennish; Frank A. von Hippel; Richard Bernhardt; Mark E. Hines (pp. 881-887).
The perchlorate anion (ClO 4 − ) is an anthropogenic contaminant of increasing concern in water supplies, and has been shown to disrupt thyroid activity. Most perchlorate analyses are currently carried out by ion chromatography (IC) with suppressed conductivity detection (SCD). While this procedure has been demonstrated to provide acceptable performance for analysis of water samples, the determination of perchlorate in high-conductivity aqueous extracts of plant or animal material is not readily accomplished by IC-SCD unless lengthy cleanup protocols are applied. With the addition of electrospray ionization mass spectrometry (ESI-MS) to IC, it was hypothesized that the interference imposed by various ionic species could be significantly reduced without the need for purification; however, the analysis of perchlorate in relatively unpurified extracts of biologically derived homogenates by IC-ESI-MS has not previously been described in the literature. The research presented here represents a comparison of the capabilities of IC-SCD and IC-ESI-MS to detect perchlorate in reagent water and in crude extracts of perchlorate-exposed fish (threespine stickleback, Gasterosteus aculeatus). ESI-MS was found to compare favorably to SCD for the detection of perchlorate in deionized water, and to exceed SCD performance in perchlorate analysis of fish-derived extracts.

Keywords: Perchlorate; Ion chromatography; Suppressed conductivity detection; Electrospray ionization mass spectrometry


Evaluation of several pneumatic micronebulizers with different designs for use in ICP–AES and ICP–MS. Future directions for further improvement by S. E. Maestre; J. L. Todolí; J. M. Mermet (pp. 888-899).
This paper reports characterization of the behavior of five pneumatic micronebulizers based on slightly different designs in inductively coupled plasma atomic-emission spectrometry and mass spectrometry (ICP–AES and ICP–MS). Two nebulizers were used as reference nebulizers, a high-efficiency nebulizer (HEN) and a micromist (MM). They were compared with a commercially available PFA (tetrafluoroethylene–perfluoroalkyl vinyl ether copolymer) nebulizer and with two new prototypes called the polymeric pneumatic concentric nebulizer (PMN) and the high-solids micronebulizer (HSM). The dimensions of the nebulizers, the gas back-pressure, and the free liquid uptake rates were measured. The study also included tertiary aerosol drop-size distributions, analyte transport rate, and analytical figures of merit, i.e. sensitivities and limits of detection, both in ICP–AES and ICP–MS. Recoveries for two food solid reference materials were also determined. Overall, the results indicated that the PFA and the HEN nebulizers provided the best results. These two nebulizers delivered a higher mass of analyte to the plasma and showed better sensitivies giving lower limits of detection than the PMN, HSM and MM. The results revealed that the liquid prefilming effect occurring before aerosol production in the PFA nebulizer promoted more efficient interaction of liquid and gas, thus affording good results even though gas back-pressure values could be maintained below 3 bar. In contrast, the HEN had to be operated at about 7 bar under the same conditions. Nebulizer design did not have a relevant effect on the recovery, which confirmed that the spray chamber plays an important role in terms of non-spectroscopic interferences.

Keywords: ICP–AES; ICP–MS; Pneumatic micronebulizers; Food analysis; Liquid prefilming
Featured Book
Web Search
Powered by Plone CMS, the Open Source Content Management System

This site conforms to the following standards: