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Kuonen M, Hattendorf B, Günther D. Quantification capabilities of N 2 MICAP-MS with solution nebulization and aerosol desolvation. JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY 2024; 39:1388-1397. [PMID: 38737797 PMCID: PMC11079722 DOI: 10.1039/d4ja00058g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 03/21/2024] [Indexed: 05/14/2024]
Abstract
The analytical capabilities of a nitrogen-sustained high-power microwave inductively coupled atmospheric-pressure plasma mass spectrometer (N2 MICAP-MS) were investigated using solution nebulization with and without aerosol desolvation. The reduced solvent load for the desolvated aerosol and the increased aerosol transfer resulted in a signal enhancement of ten times for most elements in samples without a significant amount of dissolved solids. An exception was boron, whose signal decreased by a factor of seven when a desolvator was used. To compare the accuracy, reproducibility, and matrix susceptibility of the N2 MICAP-MS, the mass fractions of 30 elements were determined in two certified water reference materials using external calibration and standard addition. The results were generally found to agree within 10% of the certified reference values with a maximum deviation of 17% in the case of 64Zn. Comparing external calibration and standard addition provided comparable results regardless of the sample introduction method. To assess the extent of matrix effects, multi-element standard solutions were doped with amounts of up to 100 mg kg-1 calcium. This resulted in a signal suppression of up to 30% and 70% for conventional nebulization and aerosol desolvation, respectively. This substantially reduced the improvement in sensitivity observed for the desolvated aerosol. To further investigate the fundamental characteristics of the N2 MICAP-MS, the plasma gas temperature was estimated using three methods. The determined temperatures for the two most reliable methods were in the range of ∼5000-6000 K and were found to be independent of the sample introduction method and similar to those of an Ar ICP.
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Affiliation(s)
- Monique Kuonen
- Department of Chemistry and Applied Biosciences, Laboratory of Inorganic Chemistry, ETH Zurich Vladimir-Prelog-Weg 1 8093 Zurich Switzerland
| | - Bodo Hattendorf
- Department of Chemistry and Applied Biosciences, Laboratory of Inorganic Chemistry, ETH Zurich Vladimir-Prelog-Weg 1 8093 Zurich Switzerland
| | - Detlef Günther
- Department of Chemistry and Applied Biosciences, Laboratory of Inorganic Chemistry, ETH Zurich Vladimir-Prelog-Weg 1 8093 Zurich Switzerland
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2
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You Z, Winckelmann A, Vogl J, Recknagel S, Abad C. Determination of calcium, iron, and selenium in human serum by isotope dilution analysis using nitrogen microwave inductively coupled atmospheric pressure plasma mass spectrometry (MICAP-MS). Anal Bioanal Chem 2024; 416:3117-3125. [PMID: 38589614 PMCID: PMC11068692 DOI: 10.1007/s00216-024-05274-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 03/12/2024] [Accepted: 03/13/2024] [Indexed: 04/10/2024]
Abstract
In this study, we demonstrate the applicability of nitrogen microwave inductively coupled atmospheric pressure mass spectrometry (MICAP-MS) for Ca, Fe, and Se quantification in human serum using isotope dilution (ID) analysis. The matrix tolerance of MICAP-MS in Na matrix was investigated, revealing that high Na levels can suppress the signal intensity. This suppression is likely due to the plasma loading and the space charge effect. Moreover, 40Ca and 44Ca isotopic fractionation was noted at elevated Na concentration. Nine certified serum samples were analyzed using both external calibration and ID analysis. Overestimation of Cr, Zn, As, and Se was found in the results of external calibration, which might result from C-induced polyatomic interference and signal enhancement, respectively. Further investigations performed with methanol showed a similar enhancement effect for Zn, As, and Se, potentially supporting this assumption. The mass concentrations determined with ID analysis show metrological compatibility with the reference values, indicating that MICAP-MS combined with ID analysis can be a promising method for precise Ca, Fe, and Se determination. Moreover, this combination reduces the influence of matrix effects, broadening the applicability of MICAP-MS for samples with complex matrixes.
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Affiliation(s)
- Zengchao You
- Bundesanstalt für Materialforschung und -Prüfung (BAM), Department 1 Analytical Chemistry; Reference Materials, Richard-Willstätter-Straße 11, 12489, Berlin, Germany.
| | - Alexander Winckelmann
- Bundesanstalt für Materialforschung und -Prüfung (BAM), Department 1 Analytical Chemistry; Reference Materials, Richard-Willstätter-Straße 11, 12489, Berlin, Germany
- Humboldt-Universität Zu Berlin, Department of Chemistry, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Jochen Vogl
- Bundesanstalt für Materialforschung und -Prüfung (BAM), Department 1 Analytical Chemistry; Reference Materials, Richard-Willstätter-Straße 11, 12489, Berlin, Germany
| | - Sebastian Recknagel
- Bundesanstalt für Materialforschung und -Prüfung (BAM), Department 1 Analytical Chemistry; Reference Materials, Richard-Willstätter-Straße 11, 12489, Berlin, Germany
| | - Carlos Abad
- Bundesanstalt für Materialforschung und -Prüfung (BAM), Department 1 Analytical Chemistry; Reference Materials, Richard-Willstätter-Straße 11, 12489, Berlin, Germany.
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Serrano R, Grindlay G, Gras L, Mora J. Microwave-sustained inductively coupled atmospheric-pressure plasma (MICAP) for the elemental analysis of complex matrix samples. Talanta 2024; 271:125666. [PMID: 38271842 DOI: 10.1016/j.talanta.2024.125666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 12/23/2023] [Accepted: 01/12/2024] [Indexed: 01/27/2024]
Abstract
Microwave induced plasma optical emission spectrometry (MIP-OES) has gained widespread attention in the last few years for trace elemental analysis. Among the new generation of MIPs it is worth to mention the microwave-sustained inductively coupled atmospheric-pressure plasma (MICAP) for which previous works have shown similar detection capabilities to those afforded by ICP-OES. Nevertheless, this instrument has not been applied yet to complex matrix sample analysis. Therefore, the goal of this work is to evaluate MICAP-OES performance (e.g., analytical figures of merit, matrix effects, etc.) for elemental analysis of samples of different nature (e.g., environmental, food and polymers). To this end, both spectral and non-spectral interferences were investigated for 19 elements (Ag, Al, As, B, Ca, Cd, Co, Cr, Cu, Fe, Ga, In, Mg, Mn, Ni, Pb, Sr, Tl, Zn) in the presence of inorganic acid, organic and saline solutions and compared to a 5 % w w-1 HNO3 solution. Unlike previous MIPs, experimental data showed that the optimum nebulizer gas flow rate for a given emission wavelength was mostly independent of matrix characteristics. Regarding matrix effects, this device was highly robust operating both inorganic acid and organic matrices. Interestingly, when operating saline matrices, changes on emission signal by easily ionizable elements were less significant than those early reported by alternative MIP cavities. Moreover, due to MICAP spectrometer design employed allows real-time simultaneous analysis, Rh, Pd, Sc and Y were suitable internal standards to minimize non-spectral interferences. Finally, MICAP-OES can be successfully applied to the elemental analysis of different complex matrix samples (i.e., CRM-DW1 Drinking water; BCR-146 Sewage sludge industrial; BCR-185 Bovine liver; BCR-278R Mussel tissue; NIST-1549 Non-fat milk powder; ERM-EC681k Polyethylene (high level) and BCR-483 Sewage sludge amended soil).
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Affiliation(s)
- Raquel Serrano
- Department of Analytical Chemistry, Nutrition and Food Sciences, University of Alicante, PO Box 99, 03080 Alicante, Spain.
| | - Guillermo Grindlay
- Department of Analytical Chemistry, Nutrition and Food Sciences, University of Alicante, PO Box 99, 03080 Alicante, Spain
| | - Luis Gras
- Department of Analytical Chemistry, Nutrition and Food Sciences, University of Alicante, PO Box 99, 03080 Alicante, Spain
| | - Juan Mora
- Department of Analytical Chemistry, Nutrition and Food Sciences, University of Alicante, PO Box 99, 03080 Alicante, Spain
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Martínez S, Sánchez R, Todolí JL. High temperature total consumption sample introduction system coupled to microwave plasma optical emission spectrometry (MIP-OES) for the analysis of aqueous samples. Anal Chim Acta 2023; 1249:340948. [PMID: 36868775 DOI: 10.1016/j.aca.2023.340948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 01/10/2023] [Accepted: 02/05/2023] [Indexed: 02/08/2023]
Abstract
The high temperature torch integrated sample introduction system (hTISIS) is coupled to microwave plasma optical emission spectrometry (MIP-OES) for the first time. The goal of this work is to develop an accurate analysis of digested samples under continuous sample aspiration mode by coupling the hTISIS to a MIP-OES instrument. To achieve this, different operating conditions such as, nebulization flow rate, liquid flow rate and the spray chamber temperature were optimized in terms of sensitivity, limits of quantification (LOQs) and background equivalent concentration (BECs) for the determination of Ca, Cr, Cu Fe, K, Mg, Mn, Na, Pb and Zn, and these values were compared with those reported with a conventional sample introduction system. Under optimum conditions (0.8-1 L min-1, 100 μL min-1 and 400 ᵒC, respectively), the hTISIS improved MIP-OES analytical figures of merit and shortened 4-times wash out times with respect to a conventional cyclonic spray chamber, reporting an enhancement factor in the sensitivity among 2-47 times and LOQs from 0.9 to 360 μg kg-1. Once the best operating conditions were set, the magnitude of the interference caused by 15 different acid matrices (2, 5 and 10% w/w of HNO3, H2SO4, HCl and mixtures of HNO3 with H2SO4 and HNO3 with HCl) was significantly lower for the former device. Finally, 6 different digested oily samples (used cooking oil, animal fat, corn oil and the same samples after a filtration step) were analyzed by means of an external calibration approach based on the use of multielemental standards prepared in 3% (w/w) HCl solution. The obtained results were compared against those supplied by a conventional methodology employing an inductively coupled plasma optical emission spectrometry, ICP-OES, instrument. It was clearly concluded that the hTISIS coupled to MIP-OES afforded similar concentrations as compared to the conventional methodology.
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Affiliation(s)
- Santiago Martínez
- Department of Analytical Chemistry, Nutrition and Food Sciences, University of Alicante, 03690, San Vicente del Raspeig, Alicante, Spain
| | - Raquel Sánchez
- Department of Analytical Chemistry, Nutrition and Food Sciences, University of Alicante, 03690, San Vicente del Raspeig, Alicante, Spain.
| | - José-Luis Todolí
- Department of Analytical Chemistry, Nutrition and Food Sciences, University of Alicante, 03690, San Vicente del Raspeig, Alicante, Spain
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Serrano R, Anticó E, Grindlay G, Gras L, Fontàs C. Determination of elemental bioavailability in soils and sediments by microwave induced plasma optical emission spectrometry (MIP-OES): Matrix effects and calibration strategies. Talanta 2021; 240:123166. [PMID: 35032786 DOI: 10.1016/j.talanta.2021.123166] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 12/19/2021] [Accepted: 12/20/2021] [Indexed: 11/19/2022]
Abstract
In the past few years, microwave induced plasma optical emission spectrometry (MIP-OES) has generated great interest as an alternative technique to inductively coupled plasma-based techniques due to its lower operational cost. Since MIP-OES suffers from severe matrix effects due to easily ionizable elements (EIEs) (Na, Ca, etc.), it is unclear whether this technique could be employed for elemental bioavailability studies in soils and sediments since the main extractant solutions employed in such works may contain high levels of these elements. Thus, the aim of this work was to evaluate the feasibility of MIP-OES as a detector for such applications. To this end, the influence of different extractant solutions (0.25 mol L-1 MgCl2, 0.25 mol L-1 CaCl2, 0.10 mol L-1 acetic acid, 0.05 mol L-1 Na2EDTA, 0.25 mol L-1 NaNO3, 0.25 mol L-1 NaOAc/HOAc and 0.10 mol L-1 NH2OH·HCl) on the analyte emission of several elements (As, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Rh, Se, Sr and Zn) was investigated. Results were compared to those obtained using a reference solution made of 5% w w-1 HNO3 solution. For saline extractant solutions, both the optimum nebulizer gas flow rate (Qg) and analyte emission were modified with regard to the reference solution. In general, the optimum Qg was reduced by between 0.1 and 0.2 L min-1 for both ionic and atomic lines. Under optimum Qg conditions, analyte emission was supressed by saline solutions except for atomic lines with an upper electronic state below 4 eV, which were enhanced. The magnitude of matrix effects was strongly dependent on EIE ionization energy. The lower the ionization energy, the greater the matrix effects were registered. No measurable matrix effects were registered on both Qg and analyte emission within experimental uncertainties for NH2OH·HCl and acetic acid extractant solutions. Experimental data suggest that matrix effects were related to changes in plasma characteristics and the analyte excitation/ionization mechanism. To mitigate matrix effects and improve long-term MIP-OES performance, internal standardization using either Rh (343.489 nm and 369.236 nm) or OH molecular emission band (308.958 nm) was required. This calibration methodology was successfully applied to the study of the elemental bioavailability in soil samples from a vineyard affected by copper-based fungicides and sediment samples from an area affected by mining waste.
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Affiliation(s)
- Raquel Serrano
- University of Alicante, Department of Analytical Chemistry, Nutrition and Food Sciences, PO Box 99, 03080, Alicante, Spain.
| | - Enriqueta Anticó
- Department of Chemistry, University of Girona, 17071, Girona, Spain
| | - Guillermo Grindlay
- University of Alicante, Department of Analytical Chemistry, Nutrition and Food Sciences, PO Box 99, 03080, Alicante, Spain
| | - Luis Gras
- University of Alicante, Department of Analytical Chemistry, Nutrition and Food Sciences, PO Box 99, 03080, Alicante, Spain
| | - Clàudia Fontàs
- Department of Chemistry, University of Girona, 17071, Girona, Spain
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Aerosol dilution as a new sample introduction strategy for microwave-induced plasma optical emission spectrometry. Anal Chim Acta 2020; 1140:41-49. [DOI: 10.1016/j.aca.2020.10.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/21/2020] [Accepted: 10/03/2020] [Indexed: 11/21/2022]
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Balaram V. Microwave plasma atomic emission spectrometry (MP-AES) and its applications – A critical review. Microchem J 2020. [DOI: 10.1016/j.microc.2020.105483] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Schild M, Gundlach-Graham A, Menon A, Jevtic J, Pikelja V, Tanner M, Hattendorf B, Günther D. Replacing the Argon ICP: Nitrogen Microwave Inductively Coupled Atmospheric-Pressure Plasma (MICAP) for Mass Spectrometry. Anal Chem 2018; 90:13443-13450. [PMID: 30350630 DOI: 10.1021/acs.analchem.8b03251] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We combine a recently developed high-power, nitrogen-sustained microwave plasma source-the Microwave Inductively Coupled Atmospheric-Pressure Plasma (MICAP)-with time-of-flight mass spectrometry (TOFMS) and provide the first characterization of this elemental mass spectrometry configuration. Motivations for assessment of this ionization source are scientific and budgetary: unlike the argon-sustained Inductively Coupled Plasma (ICP), the MICAP is sustained with nitrogen, which eliminates high operating costs associated with argon-gas consumption. Additionally, use of a commercial grade magnetron for microwave generation simplifies plasma-powering electronics. In this study, we directly compare MICAP-TOFMS performance with that of an argon-ICP as the atomic ionization source on the same TOFMS instrument. Initial results with the MICAP source demonstrate limits of detection and sensitivities that are, for most elements, on par with those of the ICP-TOFMS. The N2-MICAP source provides a much "cleaner" background spectrum than the ICP; absence of argon-based interferences greatly simplifies analysis of isotopes such as 40Ca, 56Fe, and 75As, which typically suffer from spectral interferences in ICP-MS. The major plasma species measured from the N2-MICAP source include NO+, N2+, N+, N3+, O2+, N4+, and H2O+; we observed no plasma-background species above mass-to-charge 60. Absence of troublesome argon-based spectral interferences is a compelling advantage of the MICAP source. For example, with MICAP-TOFMS, the limit of detection for arsenic is less than 100 ng L-1 even in a 1% NaCl solution; with ICP-MS, 35Cl40Ar+ interferes with 75As+ and arsenic analysis is difficult-to-impossible in chlorine-containing matrices.
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Affiliation(s)
- Matthias Schild
- Department of Chemistry and Applied Biosciences , ETH Zurich , Vladimir-Prelog-Weg 1 , 8093 Zurich , Switzerland
| | - Alexander Gundlach-Graham
- Department of Chemistry and Applied Biosciences , ETH Zurich , Vladimir-Prelog-Weg 1 , 8093 Zurich , Switzerland
| | - Ashok Menon
- Radom Corporation , 10521 W Forest Home Avenue , Milwaukee , Wisconsin United States
| | - Jovan Jevtic
- Radom Corporation , 10521 W Forest Home Avenue , Milwaukee , Wisconsin United States
| | - Velibor Pikelja
- Radom Corporation , 10521 W Forest Home Avenue , Milwaukee , Wisconsin United States
| | - Martin Tanner
- TOFWERK AG , Uttigenstrasse 22 , 3600 Thun , Switzerland
| | - Bodo Hattendorf
- Department of Chemistry and Applied Biosciences , ETH Zurich , Vladimir-Prelog-Weg 1 , 8093 Zurich , Switzerland
| | - Detlef Günther
- Department of Chemistry and Applied Biosciences , ETH Zurich , Vladimir-Prelog-Weg 1 , 8093 Zurich , Switzerland
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