Microconcentric Nebulizer Research Articles

Evaluation of a Desolvating Microconcentric Nebulizer in Inductively Coupled Plasma Mass Spectrometry to Improve the Determination of Arsenic in Steels

A desolvating microconcentric nebulizer (D-MCN) was used in inductively coupled plasma mass spectrometry (ICP-MS) in order to improve the determination of As in steels. To dissolve the samples, we applied a hydrochloric-nitric-hydrofluoric acid decomposition procedure. The isobaric interference of 40Ar35Cl+ due to the presence of Cl from the hydrochloric acid was minimized by using the desolvating device. Compared to results achieved with cross-flow nebulization, the As sensitivity was found to be 2.4 times higher, while the depression matrix effect caused by 0.1% m/v of Fe in the As signal was 3 times lower. The limit of quantification (LOQ) calculated as the concentration corresponding to 10 times the standard deviation of a procedural blank solution (0.1% m/v pure iron solution) was 0.12 μg g−1 (10 times better than that for the cross-flow nebulizer), and the background equivalent concentration (BEC) was about 25 times lower due to the absence of the most significant polyatomic interferences. The relative standard deviation calculated from six replicates at a concentration level of 10 times the detection limit was 0.8%. Three certified reference materials from the National Institute of Standard and Technology—NIST 365, 2165, and 2167—were analyzed; and recovery tests were performed on pure iron solutions spiked with different As contents. The close agreement of the values demonstrates the accuracy of the method.

Precise isotope ratio measurements for uranium, thorium and plutonium by quadrupole-based inductively coupled plasma mass spectrometry

Precise long-term measurements of uranium and thorium isotope ratios was carried out in 1 μg/L solutions using a quadrupole inductively coupled plasma mass spectrometer (ICP-QMS). The isotopic ratios of uranium (235U/ 238U = 1, 0.02 and 0.00725) were determined using a cross-flow nebulizer (CFN, at solution uptake rate of 1 mL/min) and a low-flow microconcentric nebulizer (MCN, at solution uptake rate of 0.2 mL/min) over 20 h. For 1 μg/L uranium solution (235U/238U = 1) relative external standard deviations (RESDs) of 0.05% and 0.044% using CFN and MCN, respectively, can be achieved. Additional short term isotope ratio measurements using a direct injection high-efficiency nebulizer (DIHEN) of 1 μg/L uranium solution (235U/238U = 1) at a solution uptake rate of 0.1 mL/min yielded an RSD of 0.06–0.08%. The sensitivity of solution introduction by DIHEN for uranium, thorium and plutonium (145 MHz/ppm, 150 MHz/ppm and 177 MHz/ppm, respectively) increased significantly compared to CFN and MCN and the solution uptake rate can be reduced to 1 μL/ min in DIHEN-ICP-MS. Isotope ratio measurements at an ultralow concentration level (e.g. determination of 240Pu/ 239Pu isotope ratio in a 10 ng/L Pu waste solution) were carried out for the characterization of radioactive waste and environmental samples.

A new interface for combining capillary electrophoresis with inductively coupled plasma-mass spectrometry

This paper describes the development and design of a new, efficient, simple and robust interface for coupling capillary electrophoresis (CE) with inductively coupled plasma-mass spectrometry. The interface is based on a modified microconcentric nebulizer which permits a low flow rate of about 6 μL/min in the free aspiration mode. This interface construction provides an electrical connection for stable electrophoretic separations and adapts the flow rate of the electro-osmotic flow inside the CE capillary to the flow rate of the nebulizer for efficient transport of the analytes into the plasma. By optimization of the fluid mechanical properties the interface prevents the nebulizer from causing any laminar flow in the CE capillary and thus the high resolution power of CE can be preserved. Furthermore, this new device permits independent optimization of the nebulization from the CE whereby exact positioning of the CE capillary is not necessary, thus enabling fast exchange. A low dead volume spraychamber has been constructed which circumvents any band broadening of the sharp CE signals. Peak widths down to 3.5 s comparable to CE with UV detection are possible.

Ultratrace and Isotope Analysis of Long-Lived Radionuclides by Inductively Coupled Plasma Quadrupole Mass Spectrometry Using a Direct Injection High Efficiency Nebulizer

The direct injection high efficiency nebulizer (DIHEN) was explored for the ultrasensitive determination of long-lived radionuclides ((226)Ra, (230)Th, (237)Np, (238)U, (239)Pu, and (241)Am) and for precise isotope analysis by inductively coupled plasma mass spectrometry (ICPMS). The DIHEN was used at low solution uptake rates (1-100 μL/min) without a spray chamber. Optimal sensitivity (e.g., (238)U, 230 MHz/ppm; (230)Th, 190 MHz/ppm; and (239)Pu, 184 MHz/ppm) was achieved at low nebulizer gas flow rates (0.16 L/min), high rf power (1450 W), and low solution uptake rates (100 μL/min). The optimum parameters varied slightly for the two DIHENs tested. The detection limits of long-lived radionuclides in aqueous solutions varied from 0.012 to 0.11 ng/L. The sensitivity of the DIHEN was improved by a factor of 3 to 5 compared with that of a microconcentric nebulizer (MicroMist used with a minicyclonic spray chamber at a solution uptake rate of 85 μL/min) and a factor of 1.5 to 4 compared with that of a conventional nebulizer (cross-flow used with a Scott type spray chamber at a solution uptake rate of 1 mL/min). The precision of the DIHEN ranged from 0.5 to 1.7% RSD (N = 3) for all measurements at the 10 ng/L concentration level (∼3 pg sample size). The sensitivity decreased to 10 MHz/ppm at a solution uptake rate of 1 μL/min. The precision was about 5% RSD at a sample size of 30 fg for each long-lived radionuclide by the DIHEN-ICPMS method. The oxide to atom ratios were less than 0.05 (except ThO(+)/Th(+) ) and decreased under the optimum conditions in the following sequence: ThO(+)/Th(+) > UO(+)/U(+) > NpO(+)/Np(+) > PuO(+)/Pu(+) > AmO(+)/Am(+) > RaO(+)/Ra(+). Atomic and oxide ions were used as analyte ions for ultratrace and isotope analyses of long-lived radionuclides in environmental and radioactive waste samples. The analytical methods developed were applied to the determination of long-lived radionuclides and isotope ratio measurements in different radioactive waste and environmental samples using the DIHEN in combination with quadrupole ICPMS. For instance, the (240)Pu/(239)Pu isotope ratio was measured in a radioactive waste sample at a plutonium concentration of 12 ng/L. This demonstrates a main advantage of DIHEN-ICPMS compared with α-spectrometry, which cannot be used to selectively determine (239)Pu and (240)Pu because of similar α energies (5.244 and 5.255 MeV, respectively).

Comparison of a Cross-Flow and Microconcentric Nebulizer for Chemical Speciation Measurements Using CZE-ICP-MS

A standard cross-flow nebulizer and commercially available microconcentric nebulizer (MCN-100) have been compared for capillary zone electrophoresis (CZE) inductively coupled plasma mass spectrometry (ICP-MS) measurements. Metallothionein samples were separated and detected to characterize the performance of the two nebulizers for chemical speciation measurements. The MCN-100 offered improved sensitivity and lower detection limits compared to the cross-flow nebulizer, but provided slightly poorer resolution. The detection limit for 114Cd in metallothionein solutions was 90 ng/g with the cross-flow nebulizer and 10 ng/g with the MCN-100 for ∼ 4 nL injections. These values correspond to absolute detection limits of 360 fg Cd in the injected sample with the cross-flow nebulizer and 40 fg Cd for the MCN-100. Quantitation of Cd in metallothioneins (rabbit liver and horse kidney) with the use of a well-characterized rabbit liver metallothionein sample as the calibration standard is reported. Measured Cd concentrations agreed with results obtained by both graphite furnace atomic absorption spectroscopy (AAS) and solution nebulization ICP-MS.

Evaluation of a commercially available microbore anion exchange column for chromium speciation with detection by ICP-mass spectrometry and hyphenation with microconcentric nebulization

The potential of a new commercially available microbore anion exchange column for chromium speciation (Cetac ANX-3202) was evaluated and its characteristics were studied. Nitric acid was used as mobile phase, making the technique ideal for coupling with inductively coupled plasma mass spectrometry (ICPMS). Because of the low operating flow rate of the column, a microconcentric nebulizer was used as an interface between the microbore column and the ICP-mass spectrometer. Co was added to the mobile phase and its signal intensity was continuously monitored and used as an internal standard to correct for signal drift and instrumental instability. Excellent results were obtained in terms of repeatability. Detection limits for Cr(III) and Cr(VI) are less than I μg. L -1 , using either 52 Cr or 53 Cr. The accuracy was determined by analyzing a certified reference material (BCR CRM 544). The concentrations found were in good agreement with those certified. The occurrence of C- and Cl-based molecular ions was studied and their influence on the determination of chromium was evaluated.

Determination of long-lived radionuclides by inductively coupled plasma quadrupole mass spectrometry using different nebulizers

Different nebulizers (cross-flow, ultrasonic and two microconcentric nebulizers) were used for sample introduction of radioactive solutions into a quadrupole-based inductively coupled plasma mass spectrometer (ICP-QMS). The best sensitivity (from 420 to 850 MHz, which is about one order of magnitude higher in comparison with the cross-flow nebulizer) for long-lived radionuclides ( 226 Ra, 230 Th, 237 Np, 238 U and 241 Am) was observed using the ultrasonic nebulizer. However, using the ultrasonic nebulizer, a significantly higher sample size (26-fold) in comparison with the micronebulizers is required. Sample introduction by micronebulization with a small sample size in the low picogram range is the method of choice for the determination of long-lived radionuclides. The precision of determination of a 10 ng l –1 concentration was in the low-% range (and sub-% range) for all measurements using different nebulizer types. The detection limits for the determination of long-lived radionuclides in aqueous solutions applying the different nebulizers were 0.01-0.6 ng l –1 . The flow injection analysis approach was optimized for isotope dilution analysis of 232 Th (using 20 µl of 5 µg l –1 230 Th) by ICP-QMS. The isotopic abundance ratios of 230 Th- 232 Th isotope mixtures ( 230 Th/ 232 Th=0.01, 0.001 and 0.0001) were determined using a microconcentric nebulizer and 1 µg l –1 Th solutions with a relative external standard deviation of long-term stability measurements (over 20 h) of 0.17, 0.62 and 2.66%, respectively.

Trace element determination in alpine snow and ice by double focusing inductively coupled plasma mass spectrometry with microconcentric nebulization

Double focusing inductively coupled plasma mass spectrometry (ICP-MS) has been applied to the direct, simultaneous determination of Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Mo, Ag, Cd, Sb, Ba, Au, Pb, Bi and U in recent Alpine snow and old ice at the ng g –1 and pg g –1 level. Small amounts of sample (about 1 ml) were analysed using a microconcentric nebulizer. To avoid possible spectral interferences, measurements were carried out both in medium (m/Δm≈3400) and low (m/Δm≈300) resolution modes. Clean procedures were adopted both in the field and in the laboratory in order to reduce the possibility of sample contamination to a minimum. Concentration ranges of Alpine surface snow were (in pg g –1 ): Ti (8-106×10 3 ), V (3-4601), Cr (3-2985), Mn (1-173×10 3 ), Fe (67-1058×10 3 ), Co (2-973), Cu (8-29.1×10 3 ), Zn (2-6311), Mo (11-721), Ag (0.5-107), Cd (16-218), Sb (1.7-6173), Ba (9-36.5×10 3 ), Pb (23-33.7×10 3 ), Bi (0.1-116) and U (0.1-265). Much lower concentrations were detected in high altitude sites in the Alps. Measurement repeatability, in terms of RSD, ranged between 9 and 34%, depending on the element. The reliability of the analytical method was confirmed by analysis of a certified reference material (SLRS-3, riverine water) and by determination of Cd, Pb, Cu and Zn by ETAAS. For some of the elements investigated these results constitute the first available for recent Alpine snow and old ice.

Miniaturisation of a matrix separation/preconcentration procedure for inductively coupled plasma mass spectrometry using 8-hydroxyquinoline immobilised on a microporous silica frit

A comparison has been performed on miniaturised matrix separation/preconcentration procedures using packed micro-columns of imminodiacetate (IDA) chelating reagents and an 8-hydroxyquinoline (8-HQ) micro-column. Commercially available IDA reagents, Prosep and Muromac, were packed into micro-columns and 8-HQ has been immobilised on a novel microporous silica structure. These have been successfully utilised for the determination of several trace elements in complex matrix samples. The miniaturised matrix separation/preconcentration procedures have been developed to reduce sample analysis time. A microconcentric nebuliser in the ICP-MS permits the multielement analysis on a smaller volume of solution leading to a reduction in reagent consumption and a more efficient procedure. Preparation of the micro-columns is described along with optimisation of the procedures with respect to the variables buffer concentration, buffer pH, eluent acid concentration and reagent flow rates. Sample analysis times are compared for both miniaturised systems. Analysis times of 3.0 min for the IDA column and 2.3 min for the 8-HQ column are reported. Calibrations showed good linearity with correlation coefficients of 0.999–0.9998 for IDA columns and 0.999–0.9997 for 8-HQ column for a range of analytes. Recoveries ranging from 91–102% for IDA columns and 96–105% for the 8-HQ column are reported for a range of elements. The method was validated by the analysis of estuarine (SLEW-1) and coastal (CASS-2) certified reference materials. Good agreement between the certified and reference values was obtained for the materials.

A fast method for the simultaneous determination of 230Th, 234U and 235U with isotope dilution sector field ICP-MS

A double focussing sector field ICP-MS with its variable resolution capability was used for the simultaneous measurement of Th and U isotopes to calculate excess 230Th and total U content in marine sediments. The necessary separation and concentration of Th and U from major and minor elements in the sediment samples was achieved by acid digestion followed by anion exchange. ICP-MS measurements were performed using a resolution of R = 4430 resulting in an abundance sensitivity of 230/232 = 5 × 10–7 which is small enough for the quantification of sediments with 230Th/232Th ratios as low as 10–6. Using a microconcentric nebulizer (MCN-100), the lowest sample volume required for a single measurement was less than 200 µl. Analysis time was 80 s per sample. 229Th and 236U were used for quantification and as yield tracers. The overall uncertainty introduced by the entire separation procedure and the ICP-MS analyses was about 5% (95% confidence interval). The precision of each individual measurement was within 3% (2s).

Speciation of six arsenic compounds using capillary electrophoresis-inductively coupled plasma mass spectrometry

Capillary electrophoresis (CE) was used to separate four anionic {arsenite [As(III)], arsenate [As(V)], monomethylarsonic acid and dimethylarsinic acid} and two cationic forms (arsenobetaine and arsenocholine) of As in a single run. At sufficiently high concentrations, the determination of these compounds could be accomplished by means of UV detection. The determination of low concentrations (<10 µg l –1 ) of these compounds of interest was accomplished by coupling CE on-line with inductively coupled plasma mass spectrometry (ICP-MS). To accomplish this coupling, a microconcentric nebulizer was used. The modifications necessary to make a conventional CE system compatible with ICP-MS, the optimization of the operation parameters and of sample stacking conditions together with the effect of the sheath liquid and of an induced laminar flow are discussed. The analytical figures of merit of the method were assessed and the limit of determination (based on the peak height of a peak for which the signal-to-noise ratio is 10:1) was found to be 1-2 µg l –1 As for each species. The recovery for the compounds of interest was determined using a spiked mineral water sample. Samples of mineral water, soil leachate and urine were analyzed with the CE-ICP-MS combination.

Determination of rare earth elements U and Th in environmental samples by inductively coupled plasma double focusing sectorfield mass spectrometry (ICP-SMS)

The excellent capability of high resolution inductively coupled plasma sectorfield mass spectrometry for measurements of the rare earth elements Th and U is demonstrated by investigating different materials such as geological matrices (sediments, soils), plant tissues and marine animal tissues. Appropriate digestion of the samples resulted in complex matrices, especially in the case of silicate containing samples. The elemental loss in silicate residues of plant material was found to be up to 30% and therefore required HF-containing digestion methods. The high concentration of matrix elements leads to spectral interferences, which are investigated by measuring the elements with different mass resolution. High mass resolution is shown to be a prerequisite for accurate determination of Sc and Y, respectively. Furthermore, effects of non spectral interferences are investigated and could be properly corrected for by using 115 In as internal standard. Moreover, the capability of a microconcentric nebulizer in combination with a membrane desolvation unit compared to a conventional microconcentric nebulizer is discussed with respect to suppression of spectral interferences. Oxide interferences could be reduced to a negligible amount, whereas it could be observed that high salt freight leads to a blockage of the membrane.

Comparison of characteristics and limits of detection of pneumatic micronebulizers and a conventional nebulizer operating at low uptake rates in ICP-AES

Three micronebulizers, the high-efficiency nebulizer (HEN), the microconcentric nebulizer (MCN) and the micromist (MM), were compared with a conventional pneumatic concentric nebulizer working at low liquid flow rates in ICP-AES. The gas back-pressure, the free liquid aspiration rate, the drop size distribution of primary and tertiary aerosols, the solvent and analyte transport rates, the emission intensity and the limits of detection were measured. The solvent evaporation inside the spray chamber proved to be a very important transport phenomenon when working at very low liquid flow rates. The micronebulizers produced finer primary aerosols, higher solution transport rates through the spray chamber and higher sensitivities than the conventional pneumatic concentric nebulizer. The HEN used in this work provided slightly lower ICP-AES limits of detection than the other two micronebulizers, but at the expense of a higher back-pressure.

Determination of arsenic in organic solvents and wines using microscale flow injection inductively coupled plasma mass spectrometry

S. Wangkarn and S. A. Pergantis, J. Anal. At. Spectrom., 1999, 14, 657 DOI: 10.1039/A900067D

Precise sulfur isotope ratio measurements in trace concentration of sulfur by inductively coupled plasma double focusing sector field mass spectrometry

T. Prohaska, C. Latkoczy and G. Stingeder, J. Anal. At. Spectrom., 1999, 14, 1501 DOI: 10.1039/A901973A

Application of double-focusing sector field ICP mass spectrometry with shielded torch using different nebulizers for ultratrace and precise isotope analysis of long-lived radionuclides

The capability of double-focusing sector field ICP-MS with a plasma-shielded torch using different nebulizers (a Meinhard nebulizer with a Scott-type spray chamber with a solution uptake rate of 1 ml min –1 ; a MicroMist microconcentric nebulizer used with a minicyclonic spray chamber with a solution uptake rate of 0.085 ml min –1 ; an ultrasonic nebulizer with a solution uptake rate of 2 ml min –1 ; and a direct injection high-efficiency nebulizer with a solution uptake rate of 0.085 ml min –1 ) for the introduction of radioactive sample solutions into the ICP was investigated. The total amount of analyte for each long-lived radionuclide ( 226 Ra, 230 Th, 237 Np, 238 U, 239 Pu and 241 Am; concentration of each was 1 ng l –1 in the aqueous solution) using different nebulizers was 5 pg for the Meinhard nebulizer, 0.4 pg for the MicroMist microconcentric nebulizer and 10 pg for the ultrasonic nebulizer. The application of the shielded torch yielded an increase in sensitivity for all these nebulizers of up to a factor of 5 compared with the original configuration without a shielded torch. Sensitivities of about 2000 MHz ppm –1 were measured for the radionuclides investigated (except for 226 Ra) using the MicroMist microconcentric nebulizer with a shielded torch. The detection limits were in the sub-pg l –1 range and the precision ranged from 1 to 2% RSD (n=5) for the 1 ng l –1 concentration level (0.4 pg sample size). A further increase in sensitivity for long-lived radionuclides of nearly one order of magnitude in comparison with the MicroMist microconcentric nebulizer was observed using ultrasonic nebulization, but the amount of analyte required was significantly higher (by a factor of 25). In contrast, the direct injection high-efficiency nebulizer (DIHEN) in double-focusing sector field ICP-MS (DF-ICP-MS) with a shielded torch resulted in a decrease in sensitivity in comparison with the unshielded torch because of a higher water load due to the direct injection of aqueous solution into the plasma. At low solution uptake rates (down to several µl min –1 ), the uranium solutions were analyzed by DIHEN-ICP-MS using a double-focusing sector field instrument with higher sensitivity than quadrupole-based ICP-MS. Flow injection was used for sample introduction to measure small sample volumes of radioactive waste solutions (20 µl). The determination of 237 Np at a concentration of 10 ng l –1 by flow injection DF-ICP-MS was possible with a precision of 2.0% (RSD, n=5). In order to avoid mass spectral interferences and matrix effects long-lived radionuclides (e.g., of U, Th and 99 Tc) were separated from the radioactive waste matrix by liquid-liquid extraction or ion exchange. The methods developed for the precise determination of the concentration and isotopic ratios of long-lived radionuclides were applied to aqueous standard solutions and radioactive wastes by double-focusing sector field ICP-MS. The precision of Pu isotopic analysis by double-focusing ICP-MS with a shielded torch was 0.2, 2 and 14% for 1000, 100 and 10 pg l –1 (amount of analyte: 500, 50 and 5 fg), respectively.

Lead isotope ratios determined by ICP-MS: Investigation of anthropogenic lead in seawater and sediment from the Gulf of Carpentaria, Australia

Lead isotope ratios and concentrations have been measured in seawater and marine sediment by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). For seawater, solvent extraction pre-concentration and the use of a micro-concentric nebulizer allowed 1 ml of concentrate to be measured for several minutes to achieve precisions in the range 0.5-1.2% relative standard deviation for 208Pb/ 206Pb and 207Pb/ 206Pb. The environmental dispersion of trace amounts of anthropogenic Pb produced distinctive Pb isotope ratio changes in seawater and marine sediments in the immediate vicinity of a PbZn concentrate shipping facility. Concentrate was found to have 208Pb/ 206Pb ratios in the range 2.21-2.25, whereas environmental background 208Pb/ 206Pb ratios were: filtered (< 0.45 μm) seawater, 2.13-2.15; unfiltered seawater, 2.06-2.10; sediment, 2.06-2.09. The combined Pb isotope ratio and concentration measurements by ICP-MS have provided a sensitive and cost effective monitoring tool allowing an unambiguous assessment of the source of Pb.

Determination of metals in saline and biological matrices by axial inductively coupled plasma atomic emission spectrometry using microconcentric nebulization

An axial inductively coupled plasma atomic emission spectrometer equipped with a commercially available microconcentric nebulizer (MCN) was evaluated for the determination of metals in saline and biological samples. The performance of the MCN was optimized regarding the sample uptake rate and nebulizer pressure in terms of signal intensity and signal-to-background ratio. The effect of increasing salt concentrations was also studied. The results were compared with those obtained with a standard concentric glass nebulizer (CGN) for sample volumes, sensitivity and stability. The MCN was shown to reduce the sample consumption from several milliliters to a few hundred microliters for multi-element analyses. The analytical performance with the MCN was generally poorer than with the CGN, but the magnitude of the effects is element dependent. For the 18 elements studied, the detection limits range from 0.05 µg l–1 (Mn) to 30.48 µg l–1 (Ca) for the CGN and from 0.13 µg l–1 (Mn) to 173.66 µg l–1 (Na) for the MCN. Increasing the salt concentration decreases both the sensitivity and signal stability obtained with both nebulizers, but the effects are more pronounced for the MCN. The method was further evaluated by analyzing three BCR reference materials: CRM 63 Milk Powder, CRM 185 Bovine Liver and CRM 278 Mussel Tissue. Overall, the results obtained with both nebulizers showed good agreement with the certified values.

Minimization of acid effects at low consumption rates in an axially viewed inductively coupled plasma atomic emission spectrometer by using micronebulizer-based sample introduction systems

Two methods were applied in order to minimize acid effects at very low liquid uptake rates in an axially viewed ICP-AES system: aerosol solvent elimination and direct injection in the plasma base. The latter choice eliminated the use of a spray chamber. Four different sample introduction systems were evaluated based on the use of micronebulizers. The first system made use of a so-called microconcentric nebulizer (MCN) associated with a double-pass Scott spray chamber. Two other systems were based on the use of a desolvation unit that consisted of a first and a second stage in which the solvent was partially removed. The solvent elimination system was either two Liebig condensers connected in series or a porous PTFE membrane. In these cases two different MCNs were coupled. The last sample introduction system employed was a direct injection nebulizer (DIN) that eliminated the contribution of the spray chamber to the acid interference. The liquid flow rates ranged from 5 to 120 µl min–1, depending on the sample introduction system employed. Nitric, hydrochloric and sulfuric acid of 0.9 mol l–1 were tested and 3.6 mol l–1 nitric acid solution was also studied in order to evaluate the acid concentration effect. The Mg II to Mg I line intensity ratio was used to evaluate any possible changes in the plasma conditions. The results showed that, for the MCN coupled to the spray chamber, the lower the liquid flow rate, the greater was the acid interference. The extension of this effect was dependent on the MCN configuration. For the desolvation systems and DIN the behavior was the opposite, the acid interference being more important as the liquid flow rate increased. For the four acids employed, and at very low liquid flow rates (below 30 µl min–1), the acid effect was eliminated by using a conventional desolvation system with a heating temperature of 160 °C, the condensation temperatures for the two condensers being 10 and 0 °C, respectively. The use of a membrane was found to be advisable because, under some conditions, acids and water gave the same analytical signal. As regards the DIN, it was able to eliminate the interference for 0.9 mol l–1 nitric and hydrochloric acid. Nevertheless, the two remaining solutions, i.e., 0.9 mol l–1 sulfuric and 3.6 mol l–1 nitric acid, gave rise to a decrease in the signal of around 20%.

Simultaneous speciation of redox species of arsenic and selenium using an anion-exchange microbore column coupled with a micro-concentric nebulizer and an inductively coupled plasma mass spectrometer as detector

Download options Please wait... Article information DOI https://doi.org/10.1039/A704772J Article type Paper Download Citation J. Anal. At. Spectrom., 1998,13, 141-149 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Simultaneous speciation of redox species of arsenic and selenium using an anion-exchange microbore column coupled with a micro-concentric nebulizer and an inductively coupled plasma mass spectrometer as detector Á. Woller, H. Garraud, J. Boisson, A. Marie Dorthe, P. Fodor and O. F. X. Donard, J. Anal. At. Spectrom., 1998, 13, 141 DOI: 10.1039/A704772J To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Social activity Tweet Share Search articles by author Ágnes Woller Hervé Garraud Jolanda Boisson Anne Marie Dorthe Péter Fodor Olivier F. X. Donard