Field Inductively Coupled Plasma Mass Spectrometry Research Articles

High-Accuracy Determination of Potassium and Selenium in Human Serum by Two-Step Isotope Dilution ICPMS.

A high-accuracy measurement technique for determining potassium and selenium in human serum was developed by using two-step Isotope Dilution Inductively Coupled Plasma-Mass Spectrometry (ICPMS) in this research. A more accessible method of the quadrupole ICPMS was employed in this research to achieve an equally high accuracy which had been achieved by a much more expensive method, namely, high-resolution sector field ICPMS (SF-ICPMS), with a comparatively easy and simple operation. In addition, we have evaluated the uncertainty of this method. The results showed that the determination limits of potassium and selenium in serum were 0.8 mg/kg and 2.7 μg/kg, respectively, and the precision for both measurements was lower than 0.2% and 0.7%. The measurement, when employed to measure potassium and selenium in standard materials NIST956D, NIST909C, and GBW09152, had caused a maximum deviation of less than 0.9%, within the stated uncertainty range of standard materials. The RELA international inter-laboratory comparisons of potassium in serum in 2018 conducted by our laboratory also yielded a satisfactory result.

Automated preconcentration of Fe, Zn, Cu, Ni, Cd, Pb, Co, and Mn in seawater with analysis using high-resolution sector field inductively-coupled plasma mass spectrometry

A rapid, automated, high-throughput analytical method capable of simultaneous analysis of multiple elements at trace and ultratrace levels is required to investigate the biogeochemical cycle of trace metals in the ocean. Here we present an analytical approach which uses a commercially available automated preconcentration device (SeaFAST) with accurate volume loading and in-line pH buffering of the sample prior to loading onto a chelating resin (WAKO) and subsequent simultaneous analysis of iron (Fe), zinc (Zn), copper (Cu), nickel (Ni), cadmium (Cd), lead (Pb), cobalt (Co) and manganese (Mn) by high-resolution inductively-coupled plasma mass spectrometry (HR-ICP-MS). Quantification of sample concentration was undertaken using isotope dilution for Fe, Zn, Cu, Ni, Cd and Pb, and standard addition for Co and Mn. The chelating resin is shown to have a high affinity for all analyzed elements, with recoveries between 83 and 100% for all elements, except Mn (60%) and Ni (48%), and showed higher recoveries for Ni, Cd, Pb, Co and Mn in direct comparison to an alternative resin (NOBIAS Chelate-PA1). The reduced recoveries for Ni and Mn using the WAKO resin did not affect the quantification accuracy. A relatively constant retention efficiency on the resin over a broad pH range (pH 5–8) was observed for the trace metals, except for Mn. Mn quantification using standard addition required accurate sample pH adjustment with optimal recoveries at pH 7.5 ± 0.3. UV digestion was necessary to increase recovery of Co and Cu in seawater by 15.6% and 11.4%, respectively, and achieved full break-down of spiked Co-containing vitamin B12 complexes. Low blank levels and detection limits could be achieved (e.g., 0.029 nmol L−1 for Fe and 0.028 nmol L−1 for Zn) with the use of high purity reagents. Precision and accuracy were assessed using SAFe S, D1, and D2 reference seawaters, and results were in good agreement with available consensus values. The presented method is ideal for high throughput simultaneous analysis of trace elements in coastal and oceanic seawaters. We present a successful application of the analytical method to samples collected in June 2014 in the Northeast Atlantic Ocean.

Determination of Pt–DNA adducts and the sub-cellular distribution of Pt in human cancer cell lines and the leukocytes of cancer patients, following mono- or combination treatments, by inductively-coupled plasma mass spectrometry

This paper describes methodologies, based on sector field inductively-coupled plasma mass spectrometry (SF-ICP-MS), and their application in the holistic study of the fate of Pt in human cell populations following treatment with cis- or oxaliplatin and combination treatments. Pt–DNA adduct formation data at several time points has been determined in the leukocytes from patients undergoing Pt-based chemotherapy demonstrating significant inter-patient variability and excellent reproducibility of the assay. The sensitivity of the technique enabled quantitation of as little as 0.2 Pt adducts per 10 6 nucleotides using 10 μg of patient DNA. Further, the first ever reported in vivo sub-cellular Pt fractionation data on a patient sample is presented indicating the feasibility of applying the methods presented here in a clinical environment. For in vitro studies, three cell models were used: A549 human lung adenocarcinoma epithelial cells were exposed to 50 μM cisplatin for 1 h; HCA7 human colorectal cancer cells were treated with either FOLFOX (200 μM 5-fluorouracil, 200 μM folinic acid and 50 μM oxaliplatin) or 50 μM oxaliplatin; and HT29 human colorectal cancer cells were treated with 50 μM oxaliplatin in combination with 20 μM methaneseleninic acid, CH 3SeO 2H (MSA). The cells were harvested and either the DNA extracted and/or a commercially available kit used to fractionate the treated cells into four sub-cellular compartments. Each of the sub-cellular fractions and extracted DNA were digested separately, evaporated to dryness and reconstituted in 2% nitric acid for analysis by SF-ICP-MS. The sub-cellular Pt distribution for cisplatin treated A549 cells was shown to be as follows: ∼70% localized in the cytosol, ∼17% in the membrane and membrane localized fraction, ∼9% in the nuclear fraction and ∼4% in the cytoskeletal fraction. Both FOLFOX and oxaliplatin treated HCA7 cells showed comparable sub-cellular Pt distributions, and Pt–DNA adduct formation was similar for the oxaliplatin and FOLFOX treatments with adduct yields of 5.6 and 5.5 adducts per 10 6 nucleotides respectively. It was found that the combination of oxaliplatin with 20 μM MSA did not change the distribution of Pt or significantly alter its accumulation in the cytosol of the HT29 cells. Mass balance experiments showed a >99% recovery of the total Pt in the sub-cellular fractions. These experiments are the first to provide such a detailed quantitation of Pt-drug partitioning and they show that the Pt broadly follows the total protein content of the individual compartments with the majority being scavenged in the cytosol compartment.

Challenges and successes in using inductively coupled plasma mass spectrometry for measurements of tungsten in environmental water and soil samples

Military small arms ranges in the United States have been used for munitions training with tungsten rounds, which are comprised of powdered tungsten (W) pressed together with polymeric binders. As a result, W has been introduced into surface soils. The environmental and human health effects of W remain open questions. The US Army Corps of Engineers is responsible for environmental monitoring, site assessments, and cleanup of small arms ranges. This work requires routine measurements of tungsten in natural waters and soils. However, the existing sample preparation and analytical procedures were not specifically developed with W in mind for environmental analysis. Our work suggests modification of existing metal sample preparation and analytical procedures are necessary to accurately quantify W in environmental media. Our group has been actively conducting W measurements using inductively coupled plasma mass spectrometry (ICPMS), both with quadrupole and sector field ICPMS systems. We have used heavy rare earth elements and iridium as internal standards. For soils, the great majority of the W from small arms can be dissolved using acid leaching with HNO3–H3PO4 mixtures; more rigorous preparations with fusion or HF digestions can also be used. In ICPMS analysis, the largest challenge involves dealing with the significant carry-over and memory of W in sample introduction systems. This ultimately limits measurement capabilities, particularly at sub-µg L−1 levels. With careful attention to the sample and standards’ matrix constituents, and proper washout time, successful analysis is possible and ICPMS is clearly the preferred technique. A commercially available fluoropolymer sample introduction system exhibits significantly improved memory characteristics.

SF-ICP-MS Analysis of Palladium in Fluids of Patients Sensitized to Metal-Based Dental Restorations

Palladium (Pd) belongs to the platinum group elements and its use has more than doubled in the past ten years. Encouraged by positive patch test results in some patients suffering from oral syndromes, Pd was included in the routine patch testing for contact dermatitis. In the present study, differences in the trend of sensitization to Pd in a contact derma- titis clinic population between 1996 and 2006 were evaluated. Since many in vitro studies have confirmed the corrosion of dental alloys and indicated that metal components are released in the oral cavity, Pd content was examined in leaching so- lutions from dental prostheses and in samples of saliva, serum and urine of subjects with adverse reaction to dental pros- theses. Measurements were performed by means of Sector Field Inductively Coupled Plasma-Mass Spectrometry (SF- ICP-MS). Results showed that the frequency of mono-reactions to Pd are increased from 1996 (0.11%) to 2006 (1.6%), suggesting that this metal is becoming a new potential allergen. The mean values of Pd levels detected in urine were higher than those found in saliva and in serum. All biological samples collected from patients showed significantly higher levels of Pd than controls (saliva, 255 ng/L vs 11; serum, 60 vs 15; urine, 580 vs 20). Moreover, after removal of the pros- theses a consistent reduction of Pd content in fluids was observed.

Application of inductively coupled plasma sector field mass spectrometry for elemental analysis of urine

An analytical method using double focusing sector field inductively-coupled plasma mass spectrometry (sector field ICP-MS) for rapid simultaneous determination of 42 elements in urine is described. Sample preparation consisted of 20-fold dilution with 0.14 mol/l nitric acid in ultrapure water. The importance of controlling possible contamination sources at different sample preparation and analysis stages in order to achieve adequate method detection limits (DL) is emphasized. Correction for matrix effects was made using indium and lutetium as internal standards. Different approaches for accuracy assessment in urine analysis are evaluated. Additional information on trace element concentrations in a urine reference material is given. Between-batch precision was assessed from the analysis of separately prepared aliquots of the reference material and was better than 10% RSD for 32 of the elements. The robustness of the procedure was tested by analysis of about 250 samples in one analytical run lasting more than 50 hours. A statistical summary of results for 19 urine samples from non-exposed subjects is presented. For a majority of the elements tested concentrations were higher than the detection limit of the method.

Use of double-focusing sector field ICP-mass spectrometry in tracer experiments, aiming at the quantification of Mg2+ transport across the intestine of tilapia fish

Double-focusing sector field inductively coupled plasma mass spectrometry (ICP-MS) was used for the determination of 26Mg/24Mg isotope ratios in order to quantify intestinal Mg2+ transport in the fish tilapia (Oreochromis mossambicus). As the sample medium contained substantial amounts of C, Na, P, S, Cl and K, the occurrence of molecular (e.g., C2+, C2H+, CN+ and NaH+) and doubly charged (48Ca2+) ions and tailing of the 23Na+ ion signal resulted in spectral overlap at low mass resolution. Application of a higher mass resolution (R = 3000), however, permitted accurate determination of Mg isotope ratios. The usefulness of cool plasma conditions was also evaluated, but this approach was insufficient to resolve all interferences completely. After careful optimisation of the measurement parameters, it was possible to measure the 26Mg/24Mg isotope ratio with a relative standard deviation (RSD) of 0.2–0.5% (n = 10 × 30 s) at R = 3000. From the isotope ratio results obtained, net intestinal Mg2+ fluxes were calculated, providing evidence for secretory Mg2+ transport. Conclusively, the measurement of stable isotope ratios with sector field ICP-MS presents a sophisticated tool for the study of Mg2+ transport processes in biological systems that may provide an effective alternative for the use of radiotracers.

Capabilities of high resolution inductively coupled plasma mass spectrometry for trace element determination in plant sample digests

The analytical performance of inductively coupled plasma mass spectrometry (ICP-MS) for the analysis of plant sample digests was evaluated using double focusing sector field ICP-MS (ICP-SMS). Instrumental detection limits of ICP-SMS are superior to those obtained by quadrupole systems (ICP-QMS) and reach the fg mL–1 range for elements with high m/z ratios. Matrix effects caused by a plant digest after sample preparation resulting in 200-fold dilution were found to be negligible. The usefulness of high mass resolution for overcoming some spectral interferences is demonstrated. Mathematical correction possibilities could be necessary to improve accuracy. The concentrations of more than 20 elements can be determined in 5 min and only one internal standard is necessary to correct for instrumental drift.

Assessment of laser ablation and sector field inductively coupled plasma mass spectrometry for elemental analysis of solid samples

Coupling laser ablation and inductively coupled plasma mass spectrometry (ICP-MS) creates a technique which is capable of producing isotopic and elemental analyses of solid materials quickly and with a minimum of sample preparation. The instrument most often coupled with a laser ablation system features a quadrupole mass analyzer to resolve the component elements and isotopes. Other instrument designs employing electro-magnetic sector analyzers which have higher ion transmission efficiency and greater resolution capabilities to those found in traditional quadrupole instruments are also available. In this work we couple a laser ablation system to a sector field ICP-MS and illustrate that analysis of solid materials is possible. We will demonstrate that detection limits of low ppt levels are possible for a ‘bulk’ analysis whilst maintaining data precision of <10% for a large number of elements across the mass range. And finally, this work will show that single shot ‘feature’ analysis is possible with detection limits of below 10 ppb for a subset of elements, at precisions of <1%.

Influence of sample pre-treatment on the determination of trace elements in urine by quadrupole and magnetic sector field inductively coupled plasma mass spectrometry

An investigation was carried out to explore further the analytical capabilities of quadrupole and magnetic sector field inductively coupled plasma mass spectrometry (ICP-MS) in conjunction with ultrasonic nebulization (UN) for the reliable determination in human urine of nine potentially toxic and/or environmentally relevant trace elements, namely Cd, Co, Cr, Ni, Pb, Rb, Sb, Se and V. For the quantification of Cr, Ni and V magnetic sector field ICP-MS was used in the medium resolution mode (m/Δm=3000) to separate the signal of the analyte from severe polyatomic interferences caused by high concentrations of bulk elements (C, Ca and Cl). The detection power afforded by quadrupole ICP-MS, on the other hand, was adequate for the reliable determination of Cd, Co, Pb, Rb, Sb and Se. Three different sample pre-treatment steps, namely dilution of urine with high-purity water, UV irradiation and microwave digestion with concentrated HNO3 and H2O2, were investigated in detail to clarify two key issues, i.e., first, the performance, accuracy and reproducibility of the two ICP-MS systems under different matrix loads of the plasma and, second, the actual concentrations of trace elements in the urine sediment.