Triethylamine-assisted Mg(OH)2 coprecipitation/preconcentration for determination of trace metals and rare earth elements in seawater by inductively coupled plasma mass spectrometry (ICP-MS)

An AIE Controlled "Off-On" Cu2+-Sensitive Probe for Early Detection of Renal Fibrosis

Early detection of renal fibrosis (RF) is very important given that it is irreversible when it progresses to the terminal stage. A key marker of RF pathogenesis is activation of myomyofibroblasts, and its targeted imaging may be a promising approach for early detection of RF, but no study has directly imaged activation of renal myomyofibroblasts. Cu2+ plays a major role in the fibrotic activity of myofibroblasts. Herein, inspired by that Cu2+ can complex with bovine serum albumin (BSA), BSA-Ag2S quantum dots (QDs) with aggregation-induced emission (AIE) property are synthesized. Then BSA-Ag2S QDs are modified by chitosan (CS) with renal targeting and hyaluronic acid (HA) with myofibroblast targeting to obtain the AIE assay system (QDs@CS@HA). The system is simple to synthesize, and produces a rapid NIR fluorescence signal turn-on response and a low detection limit of 75 × 10-9 m to Cu2+. In addition, cellular and animal experiments have shown that QDs@CS@HA has good biosafety and cell-targeted imaging capability for RF. Based on the successful application of QDs@CS@HA and the mechanism of RF progression in early RF detection, it is expected that QDs@CS@HA may detect RF before the appearance of clinical symptoms.

Exploring Rare Earth Element behavior in the Mount Etna volcanic aquifers (Sicily)

This study presents the first data on REY (Rare Earth Elements plus Yttrium) in the aquifer of Mount Etna (Sicily, Italy). Patterns normalized to chondrites indicate strong water-rock interaction, facilitated by a slightly acidic pH resulting from the dissolution of magma-derived CO2. REY patterns provide insights into the processes of both mineral dissolution and the formation of secondary phases. The relative abundance of light to heavy rare earth elements is compatible with the prevailing dissolution of ferromagnesian minerals (e.g., olivine or clinopyroxenes), reinforced by its strong correlation with other proxies of mineral dissolution (e.g., Mg contents). Pronounced negative Ce anomalies and positive Y anomalies demonstrate an oxidizing environment with continuous formation of secondary iron and/or manganese oxides and hydroxides. The Y/Ho fractionation is strongly influenced by metal complexation with bicarbonate complexes, a common process in C-rich waters. In the studied system, the measured REY contents are always below the limits proposed by Sneller et al. (2000, RIVM report, Issue 601,501, p. 66) for surface water and ensure a very low daily intake from drinking water.

Determination of ultra-trace Te species in open ocean waters based on Mg(OH)2 coprecipitation, anion exchange resin column separation and inductively coupled plasma sector-field mass spectrometry using a 125Te-enriched isotope spike

We present a method for the determination of ultra-trace Te species (Te(IV) and Te(VI)) in open ocean waters. The proposed method is based on Mg(OH)2 coprecipitation, anion exchange resin column separation and inductively coupled plasma sector-field mass spectrometry (ICPSFMS) using a 125Te-enriched isotope spike. The largest advantage of the method is that the use of the spike allows accurate and precise determination when it combines with either isotope dilution or recovery correction. Tellurium-IV and VI are preconcentrated in a Mg(OH)2 precipitate and separated mutually by an anion exchange resin column. Te(IV) is retained to the column, while Te(VI) passing through the column is recovered by a subsequent column procedure after reduction of Te(VI) to Te(IV). Te(IV) is successfully eluted with a small amount of 0.01 M HCl. The additional merit of using this eluent is elimination of components that result in a memory effect during the measurement of Te(IV). Possible mass spectral interference on Te(IV) can be excluded by adjusting the mass window, and the Te(IV) concentrations determined by this approach agree well with those independently obtained by an oxidation procedure which removes the interference. The accuracy of the proposed method is verified with homemade standard seawater for which the measured concentrations agree well with results calculated from the value of the standard solution. Procedural blanks for Te(IV) and Te(VI) are 1.5 ± 0.9 pg kg-1 (n = 11) and 1.3 ± 0.9 pg kg-1 (n = 11) with corresponding overall detection limits of 3.0 pg kg-1 and 2.8 pg kg-1, respectively. Using the method, we have clarified vertical profiles of Te(IV) and Te(VI) in the subarctic western North Pacific for the first time.

Flexible electrode-based voltammetric detection of Y (III) ions in real water samples using an efficient CyDTA complexing strategy

The rapid detection of rare earth elements is crucial in various fields, such as materials science, biomedicine, and water quality assessment. However, no studies have reported on the detection of yttrium (Y) using electrochemical sensor-based devices. In this study, we present an innovative method for detecting Y(III) ions in aquatic environments using an electroanalytical detection platform. We have developed a complexation catalytic method that integrates trans-1,2-cyclohexanediaminetetraacetic acid (CyDTA) and silver nanoparticles (Ag NPs), thereby enhancing the adsorption and electrochemical response of Y(III) ions. The modified electrode demonstrates an 18-fold increase in the response signal of the Y(III) reduction peak compared to the bare LIG electrode. To elucidate the electrocatalytic mechanism, we conducted various interface characterization methods and DFT simulations. The Ag-CyDTA/LIG electrode exhibits excellent detection performance, with a broad linear dynamic range of 1 × 10-6 to 0.01 g/L and an exceptionally low detection limit of 0.02 μg/L. Significantly, we successfully employed the electrochemical sensing platform to analyze real water samples from rare earth ore, marking the first report on the voltammetric detection of Y(III) ions in real water samples using a flexible electrode. These findings offer a promising technical solution for the practical detection of Y(III) ions.

Trace nickel determination in seawater matrix using combination of dispersive liquid-liquid microextraction and triethylamine-assisted Mg(OH)2 method

In order to eliminate the effects of seawater matrix on the precise/accurate determination of elements, new and efficient analytical procedure requires. In this study, co-precipitation method based on the triethylamine (TEA)-assisted Mg(OH)₂ was performed to eliminate side-effects of seawater medium on the determination with flame atomic absorption spectrometry (FAAS) prior to the preconcentration of nickel by an optimized dispersive liquid-liquid microextraction (DLLME) method. Under the optimum conditions of the presented method, the limit of detection and quantification (LOD, LOQ) values obtained for nickel were found as 16.1 and 53.8 μg kg^-1, respectively. Seawater samples collected from West Antarctic region were used for real sample applications to check the accuracy and applicability of developed method, and satisfying recovery results (86-97%) were obtained. In addition to this, the digital image-based colorimetric detection system and the UV-Vis system were applied to confirm the applicability of the developed DLLME-FAAS method in other analytical systems.

Assessment of heavy metals remobilization and release risks at the sediment-water interface in estuarine environment

The influence of overlying hydrodynamics on the exchange behaviour and fluxes of heavy metals at the sediment-water interface (SWI) is poorly understood. In the study, metals exchange behaviour and exchange rate at the SWI under resuspended and undisturbed scenario were investigated The results showed that dissolved Cr, Cu, Zn, and Pb concentrations increased rapidly to attain maximum values between 0.3 and 0.5 N·m^-2 after the sediment resuspended. Following the quick release, metals concentrations gradually decreased and remained at relatively low levels, especially for Cu and Zn. Meanwhile, Cu, Zn, and Pb had higher potential remobilization potential in the undisturbed case. Calculating with the hydrodynamics in the Modaomen, the metals efflux under the resuspension scenario could reach 0.55 to 4130.83 mg·m^-2·yr^-1, which were 1-3 orders of magnitudes higher than the undisturbed case. Whether or not resuspension events occurred, estuarine sediments were source of heavy metals, especially in the weakly mixed zone.

Determination of Rare Earth Elements by Inductively Coupled Plasma–Tandem Quadrupole Mass Spectrometry With Nitrous Oxide as the Reaction Gas

Nitrous oxide (N2O) was investigated as the reaction gas for the determination of rare earth elements (REEs) by inductively coupled plasma–tandem quadrupole mass spectrometry (ICP-QMS/QMS). The use of N2O as the reaction gas apparently improved the yields of mM16O+ for Eu and Yb in the reaction cell. As a result, the sensitivities for measurement of Eu and Yb were apparently improved in comparison to those obtained with O2 as the reaction gas. A high sensitivity measurement of the whole set of REEs was achieved, providing a typical sensitivity of 300,000 CPS mL/ng for REEs measured with an isotope having isotopic abundance close to 100%. The use of N2O as the reaction gas helped suppress Ba-related spectral interferences with the measurement of Eu, permitting the measurement of Eu in a natural sample without mathematic correction of spectral interferences. The detection limits (unit, pg/mL) for 14 REEs (except for Pm) from La to Lu were 0.028, 0.018, 0.006, 0.026, 0.006, 0.010, 0.017, 0.006, 0.016, 0.010, 0.016, 0.004, 0.023, and 0.012, respectively. The validity of the present method was confirmed by determining REEs in river water-certified reference materials, namely, SLRS-3 and SLRS-4.

Green reduction of silver nanoparticles for cadmium detection in food using surface-enhanced Raman spectroscopy coupled multivariate calibration

Cadmium (Cd) causes pervasive harm on human health as a poisonous heavy metal. This study proposed a surface-enhanced Raman spectroscopy (SERS) approach using sodium alginate (SA) as green reductant in combination with edge enrichment and chemometrics to build label-free Cd quantitative models. The silver nanoparticles synthesized by SA had good dispersion and enhancement factor (3.48 × 10⁵). The optimal detection system was established by optimizing the concentration of specific molecules (trimercaptotriazine) and the droplet volume of measured liquid. Partial least squares models based on preprocessing methods and selection algorithms were compared. The results indicated that the model combined with first-order derivative preprocessing and competitive adaptive reweighted sampling algorithms achieved the best performance (R_p = 0.9989, RMSEP = 1.6225) with the limit of detection of 2.36 × 10^-5 μg L^-1 in food. The SERS approach combined with edge enrichment and chemometrics holds promise for rapid and label-free determination of Cd in food.

A novel CPE procedure by oil-in-water microemulsion for preconcentrating and analyzing thorium and uranium

A novel cloud point extraction (CPE) procedure was developed to preenrich Th4+ and UO2 2+ by oil-in-water (O/W) microemulsion. Coupling CPE to ICP-MS, the separation and analysis were achieved at a trace level, in which the low detection limits were 0.019 and 0.042 ng mL−1 for Th(IV) and U(VI), respectively. N,N′-diethyl-N,N′-ditolyl-2,9-diamide-1,10-phenanthroline (Et-Tol-DAPhen), as an extremely hydrophobic extractant, was failed to dissolve in single or mixed micelles, but was successfully solubilized to CPE system owing to O/W microemulsion. The extraction efficiency and selectivity for Th4+ and UO2 2+ were excellent under acidic condition of 1.0 mol L−1 HNO3, and the recovery of ultra-trace Th4+ and UO2 2+ was almost 100% even at the presence of large amounts of lanthanides, exhibiting high tolerance limits for lanthanides. The solubilization, extraction and coordination behaviours were studied systematically via DLS, UV–vis, 1H NMR and FT-IR. Moreover, the solubilization of N,N′-dioctyl-N,N′-dioctyl-2,9-diamide-1,10-phenanthroline (Oct-Oct-DAPhen) and efficient extraction for UO2 2+ were also realized by O/W microemulsion, which further proved the feasibility of the method.

Unraveling the Complex Composition of Produced Water by Specialized Extraction Methodologies

Produced water (PW), a waste byproduct of oil and gas extraction, is a complex mixture containing numerous organic solubles and elemental species; these constituents range from polycyclic aromatic hydrocarbons to naturally occurring radioactive materials. Identification of these compounds is critical in developing reuse and disposal protocols to minimize environmental contamination and health risks. In this study, versatile extraction methodologies were investigated for the untargeted analysis of PW. Thin-film solid-phase microextraction with hydrophilic-lipophilic balance particles was utilized for the extraction of organic solubles from eight PW samples from the Permian Basin and Eagle Ford formation in Texas. Gas chromatography-mass spectrometry analysis found a total of 266 different organic constituents including 1,4-dioxane, atrazine, pyridine, and PAHs. The elemental composition of PW was evaluated using dispersive solid-phase extraction followed by inductively coupled plasma-mass spectrometry, utilizing a new coordinating sorbent, poly(pyrrole-1-carboxylic acid). This confirmed the presence of 29 elements including rare earth elements, as well as hazardous metals such as Cr, Cd, Pb, and U. Utilizing chemometric analysis, both approaches facilitated the discrimination of each PW sample based on their geochemical origin with a prediction accuracy above 90% using partial least-squares-discriminant analysis, paving the way for PW origin tracing in the environment.

Lanthanoid analysis in seawater by seaFAST-SP3TM system in off-line mode and magnetic sector high-resolution inductively coupled plasma source mass spectrometer

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Lanthanoids as geochemical tracers in seawater.

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A 4-step strict protocol and state-of-the-art technology for lanthanoids analyses in seawaters.

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Sample pre-concentration system for matrix separation for the detection of ultra-low lanthanoids levels.

Analysis of lanthanoids in seawater is challenging due to the complex matrix (∼35 g L⁻¹ TDS) and low dissolved concentrations (in ng L⁻¹). A 4-step strict analytical protocol and state-of-the-art technology were implemented and validated in this study. The 4-steps method involves the 1) sample filtration and acidification (pH<2); 2) pre-concentration by the matrix separation system, 3) off-line injection of the eluted sample; and 4) determination of lanthanoids by high-resolution inductively coupled plasma mass spectrometer (HR-ICP-MS). Since there are no certified values for lanthanoids in seawater are available, the method validation was done by analyzing SLEW-3 (estuarine water reference samples) and comparing with other reports and artificial seawater (100 ng L⁻¹ lanthanoid multi-element standard solutions). SLEW-3 recovery varied from 78.6% to 106% and in artificial samples it ranged from 87 to 110%. Low recovery can be explained by complex organic in seawater, because the UV oxidation was not performed in the acidified samples. The variation was ≤10%, except for Gd, Tb, and Yb (11–13.75%). Blanks varied between 0.01 and 0.07 ng L⁻¹, except for La and Ce (0.13–0.21 ng L⁻¹). Blanks represent <5% SLEW-3 values and <1% synthetic seawater. The procedural detection limit varied from 0.01 to 0.03 ng L⁻¹.•

Lanthanoids as geochemical tracers in seawaters

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A 4-step strict analytical protocol and state-of-the-art technology for lanthanoids analyses in seawaters

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Sample pre-concentration system for matrix separation for the detection of ultra-low lanthanoids levels

Geogenic lanthanoid signature in coastal and marine waters from the southern Gulf of California

Lanthanoids in the southern Gulf of California (GC) seawater are reported for the first time. Lanthanoids showed differences between peninsular and continental coastline, coastal or marine ecosystems, and dry or rainy season. The chondrite-normalized values showed high variability but followed a same pattern. Light lanthanoids were more enriched than heavy ones. Values of ∑Ln and La/Lu were higher in continental than peninsular coastlines, coastal than adjacent marine ecosystems, and rainy than dry season. Differences were related to the lithology and perturbation degree of the ecosystem watersheds. The chondrite-normalized patterns are typical of geological origin. Slightly negative Ce anomaly was related to the low levels of oxygen in water for the oxidation of Ce (III) to Ce (IV) and its posterior scavenging. Negative δEu anomaly is explained by an influx of fluvial and eolian materials from the upper continental, while a positive Eu anomaly related to hydrothermal vent inputs was non-evidenced.

A new analytical approach for preconcentration, separation and determination of Pb(II) and Cd(II) in real samples using a new adsorbent: Synthesis, characterization and application

A green and efficient analytical approach was reported for simultaneous preconcentration, and separation of Pb(II) and Cd(II) in water, vegetables, and barbecue samples by dispersive solid-phase microextraction prior to their determination using flame atomic absorption spectrometry. A new poly-3-hydroxy butyrate-polyvinyl triethyl ammonium chloride comb-type amphiphilic cationic block copolymer (PHBvbNCl) was synthesized and characterized. Main variables such as pH, sorbent amount, adsorption time, eluent type, desorption time, and sample volume were optimized. Detection limits and working ranges for Pb(II) and Cd(II) were 0.03 μg L^-1, 0.15 μg L^-1, 0.1-250 μg L^-1 and 0.5-375 μg L^-1, respectively. Enhancement factor for Pb (II) and Cd (II) were 114 and 98. The adsorption capacity of PHBvbNCl for Pb(II) and Cd(II) was 175.2 mg g^-1 and 152.9 mg g^-1. After the accuracy of the method was confirmed by the analysis of certified reference materials, it was successfully applied to real samples. Finally, the analytical performance of the present method was compared with other methods.

Application of magnetic ion imprinted polymers for simultaneous quantification of Al3+ and Be2+ ions using the mean centering of ratio spectra method

Magnetic solid-phase extraction (MSPE) coupled with the spectrophotometric method for the simultaneous quantification of aluminum and beryllium ions based on mean centering of ratio (MCR) method is reported in the current work, for the first time. Two new magnetic ion-imprinted polymers (MIIPs) were synthesized using Chrome Azurol S as the ligand, (3-aminopropyl)triethoxysilane (APTES) as the functional monomer, tetraethyl orthosilicate (TEOS) as the cross-linker, and aluminum and beryllium ions as the templates, and used as magnetic sorbents. The characteristic properties of MIIPs were investigated using FT-IR spectroscopy, field emission scanning electron microscopy (FE-SEM), low angle X-ray powder diffraction (XRD), and energy-dispersive x-ray spectroscopy (EDS). Through this study, factors influencing the MSPE were studied and optimized. The proposed method exhibited good performance, with the linearity of 5.0-50.0 ng mL^-1 for aluminum ion and 2.0-40.0 ng mL^-1 for beryllium ion as well as the detection limits (DLs) of 3.2 and 0.9 ng mL^-1 for aluminum and beryllium ions, respectively. At the end of the study, the capability of the developed method for determination of target analytes was evaluated by its application in the tap and river water samples.

A primary reference method for the characterization of Cd, Cr, Cu, Ni, Pb and Zn in a candidate certified reference seawater material: TEA/Mg(OH)2 assisted ID3MS by triple quadrupole ICP-MS/MS

A certified reference seawater material (CRM), UME CRM 1206 which was sampled from the Marmara Sea (40 31,423 N; 027 11, 333 E) with 27 psu of salinity is about to be released by Inorganic Analysis Laboratory of TÜBİTAK National Metrology Institute (UME). This paper represents the characterization measurements of Cd, Cr, Cu, Ni, Pb and Zn in this CRM. The use of a reference method by a single laboratory is one of the options for the characterization of a candidate CRM according to ISO 17034 [39]. This approach is used throughout this study with an introduction of a primary reference method. For this purpose, combination of triethylamine assisted Mg(OH)₂ co-precipitation and triple isotope dilution mass spectrometry (TEA/Mg(OH)₂-ID³MS) were developed and validated. This optimized co-precipitation protocol provided the recovery of target analytes within the range of 72%-92% which was the main advantage of TEA/Mg(OH)₂ method especially for Cd, Ni, Cu and Zn compared to NH₄OH assisted co-precipitation. Analytical performance of TEA/Mg(OH)₂-ID³MS were investigated under the optimum conditions. The results for matrix certified reference material were found to be not significantly different from the certified values based on the comparison of the results and certified values within their combined uncertainties. On the other hand, intermediate precision and repeatability of the developed method were found to be in the range of 0.34%-0.90% and 0.09%-0.49%, respectively. This study reports characterization measurements with their expanded uncertainties (k = 2) as 0.4327 ± 0.0071 ng/g for Cd, 2.442 ± 0.033 ng/g for Cr, 1.018 ± 0.012 ng/g for Cu, 4.568 ± 0.037 ng/g for Ni, 1.068 ± 0.016 ng/g for Pb and 8.521 ± 0.075 ng/g for Zn where the intermediate precision was found to be the main contributor to measurement uncertainty budget of TEA/Mg(OH)₂-ID³MS method for each analyte.

Determination of rare earth elements concentrations in natural waters - A review of ICP-MS measurement approaches

Since the rare earth elements (REEs) determination in waters is still not a routine procedure, different analytical protocols have been developed to deal with complexity and variability of sample matrices, problems caused by spectral and non-spectral interferences, insufficient instruments sensitivity, potential contamination and lack of certified reference materials. The aim of this work is to review the current measurement approaches given for REEs total concentrations in natural water samples, including surface and groundwaters as well as rain water and Antarctic ice. As inductively coupled plasma mass spectrometry (ICP-MS) has become the most widely employed technique for analysis of trace concentrations of REEs in aqueous samples it has been intended to present the common issues affecting the measurement results. Apart from a sample preparation step, various configurations of mass spectrometers and sample introduction systems, means of interferences elimination or correction, and calibration strategies used in analytical approaches for REEs analysis are discussed and compared.

A Feasibility Study of Rare-Earth Element Vapor Generation by Nebulized Film Dielectric Barrier Discharge and Its Application in Environmental Sample Determination

The feasibility of 16 types of rare-earth elements (REEs) containing Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu vapor, generated simultaneously, was demonstrated by nebulized film dielectric barrier discharge (NFDBD) in this work. Note that this is the first report on the simultaneous vapor generation of 16 types of REEs, which previously was difficult to realize. Combining it with inductively coupled plasma-mass spectroscopy (ICP-MS) as the sampling technique, a 4-fold to 10-fold improvement in the detection limits (LODs) of the REEs was observed, compared with the conventional solution nebulization, and no obvious interferences from other metal ions and the mutual interferences between REEs at the mg L^-1 level were found. Compared with ultrasonic nebulization, microconcentric (MCN) and membrane-desolvation (Aridus) and electrothermal vaporization (ETV) for REEs sampling, this NFDBD sampling technique operates not only with low cost and low power, but also without any requirement of extra reagents and easy coupling with flow injection for volume limited samples. Under optimized conditions, the relative standard deviation (RSD) of 16 types of REEs determined at 5 μg L^-1 was between 0.2% and 1.9%, and the LODs of REEs were between 0.002 ng L^-1 and 0.422 ng L^-1, depending on the element. This technique provides an alternative green and highly efficient vapor generation approach for the determination of REEs in environmental samples, especially in natural water.

Simultaneous separation of arsenic and cadmium from interfering salt matrix of multivitamin/mineral supplements by sequential coprecipitation and determination by inductively coupled plasma mass spectrometry

Multivitamin/mineral (MVM) supplements possess highly saline matrix which, unless eliminated, precludes accurate determination of trace amounts of toxic metal impurities by inductively coupled plasma mass spectrometry (ICP-MS). Multi-step separations (up to four-steps) are described in literature; often for single element determinations due to difficulties in removing the matrix components. In this study, we developed a three-step sequential coprecipitation procedure for simultaneous separation of As and Cd impurities from MVM supplements for determination by ICP-MS. The procedure provided effective elimination of salt matrix, including Ca, Mg and KCl along with the interfering molybdenum (Mo) and tin (Sn) from MVM solutions. KCl, Mo and Sn were removed by two-step Mg(OH)₂ coprecipitation to about 34 µg mL^-1 K (ca. 31 µg mL^-1 Cl) and 0.4 µg mL^-1 Mo. Levels of Sn and Na were not significant. A third coprecipitation of the resulting MVM solution with HF + NH₄OH mixture precipitated virtually all Ca and Mg to as low as 1 and 10 µg mL^-1, respectively. The recoveries for As and Cd in the spiked MVM solutions were about 96% and 95%, respectively. The accuracy of the method was validated with analysis of multivitamin/multielement tablets certified reference material (SRM 3280). Experimental values were 112 ± 37 ng g^-1 for ⁷⁵As, and 76 ± 5, 79 ± 5, and 78 ± 7 ng g^-1 for ¹¹⁰Cd, ¹¹¹Cd and ¹¹⁴Cd isotopes, respectively, that were not significantly different from the certified values of As (132 ± 44 ng g^-1) and Cd (80.2 ± 0.9 ng g^-1) at 95% confidence level. Several commercially available MVM supplements were analyzed with the procedure. Mean As levels measured in the tablets varied between 24 and 128 ng g^-1 and that for Cd were between 28 and 125 ng g^-1 indicating total amount of As or Cd ingested per serving size were below the safe daily exposure limits. In addition, the results obtained for As and Cd with the procedure were lower in comparison to the values reported in literature indicating that ICP-MS analysis of complex MVM supplements could be prone to higher risks of inaccuracy without removal of interfering matrix.

Ion imprinted dual reference ratiometric fluorescence probe for respective and simultaneous detection of Fe3+ and Cu2+

Dual detection of two kinds of metal ions was achieved by a dual reference ratiometric fluorescence probe.

Microfluidic array surface ion-imprinted monolithic capillary microextraction chip on-line hyphenated with ICP-MS for the high throughput analysis of gadolinium in human body fluids

A novel method by hyphenating chip-based array ion-imprinted monolithic capillary microextraction with ICP-MS was proposed for the online analysis of trace Gd in biological samples.

Simultaneous Determination of Cr, As, Se, and Other Trace Metal Elements in Seawater by ICP-MS with Hybrid Simultaneous Preconcentration Combining Iron Hydroxide Coprecipitation and Solid Phase Extraction Using Chelating Resin

In the present study, ICP-MS with a new hybrid simultaneous preconcentration combining solid phase extraction using chelating resin and iron hydroxide coprecipitation in one batch at a single pH adjustment (pH 6.0) were developed for multielement determination of trace metal ions in seawater. In multielement determination, the present method makes it possible to determine Cr(III), As(V), Se (IV), and other 14 trace metal elements (Ti, V, Co, Ni, Cu, Zn, Zr, Ge, Cd, Sb, Sn, W, Pb, and U) in seawater. Moreover, for speciation analyses of Cr, As, and Se, the pH dependence on recovery for the different chemical forms of Cr, As, and Se was investigated. In speciation analyses, Cr, As, and Se were determined as the total of Cr (III) and a part of Cr (VI), total of As (III) and As (V), and Se(IV), respectively. Determination of total of Se and Cr(VI) remains as future task to improve. Nevertheless, the present method would have possibility to develop as the analytical method to determine comprehensively most metal elements in all standard and guideline values in quality standard in environmental water in Japan, that is, most toxic metal elements in environmental water.

Sequential coprecipitation and matrix removal for determination of cadmium impurities from multivitamin supplements by inductively coupled plasma mass spectrometry and method validation by isotope dilution analysis of SRM 3280 multivitamin/multielement tablets

In this paper, we examined three different sequential coprecipitation schemes based on Mg(OH)₂ and CaF₂ precipitation using triethylamine (TEA) and hydrofluoric acid (HF), respectively, for determination of cadmium (Cd) impurities from multivitamin/mineral (MVM) supplements by isotope dilution (ID) inductively coupled plasma mass spectrometry (ICP-MS). The schemes involved three-step coprecipitation with either TEA alone or in combination with HF and are designated as Scheme 1 (TEA-TEA-TEA), Scheme 2 (TEA-HF-TEA) and Scheme 3 (HF-TEA-TEA) according to the addition sequence of each reagent. Experiments were carried out with MVM solutions spiked with 60 μg L^-1 Cd from a multielement standard solution. All schemes provided quantitative separation of Cd from MVM matrix. Scheme 1 was the least effective in removal of interfering concomitant elements, molybdenum (Mo) and tin (Sn). Scheme 2 performed better for Sn, but failed in eliminating Mo. Scheme 3 was the most effective in eliminating both Mo and Sn. Mo levels in test MVM solutions reduced from 4.3 μg mL^-1 to as low as 0.014 μg mL^-1 while that for Sn decreased from 0.5 μg mL^-1 to 0.018 μg mL^-1 allowing interference-free determination of Cd to be achieved. Salt-matrix due to Mg, Ca, P and K along with the essential elements (Mn, Fe, Cu and Zn) levels was also reduced significantly. Reagent blanks from HF and TEA were insignificant (0.008 μg L^-1) allowing a limit of detection of 0.004 μg L^-1 or 0.26 ng g^-1 Cd to be achieved (3σ, n = 6). The performance of the coprecipitation method (Scheme 3) was validated by determination of Cd in multivitamin/multielement tablets certified reference material (SRM 3280) by ID-ICP-MS. Experimental results (ng g^-1) and recoveries were 78.8 ± 4.7 (98.5%), 77.9 ± 5.2 (97.4%) and 76.5 ± 4.8 (95.6%) for ¹¹⁰Cd, ¹¹¹Cd and ¹¹⁴Cd isotopes, respectively. Several commercial MVM supplements were analyzed using the method. Mean Cd concentration ranged from 21.4 ng g^-1 to 93.3 ng g^-1. These values are much lower than those reported to date for various MVM supplements by ICP-MS determinations without chemical separation.