Ionic imprinted polymer solid-phase extraction for inorganic arsenic selective pre-concentration in fishery products before high-performance liquid chromatography – inductively coupled plasma-mass spectrometry speciation

Low levels of inorganic arsenic [As(III) and As(V)] in fishery products have been selectively isolated from fish extracts (1.0 g of wet fish samples pre-treated with 10 mL of 1:1 methanol/water under sonication at 25 °C for 30 min) by ionic imprinted polymer (IIPs) based solid phase extraction procedure (on-column mode). The selective adsorbent was synthesized using sodium (meta) arsenite as a template, 1-vinyl imidazole as a functional monomer, divinylbenzene as a cross-linker, and 2,2′-azobisisobutyronitrile as an initiator. Optimized pre-concentration conditions imply fish extract (10 mL) pH adjustment at 8.5 before loading (flow rate of 0.25 mL min−1), and elution with ultrapure water (2 mL) at 0.50 mL min−1. A pre-concentration factor of 50 was finally obtained after evaporation to dryness (N2 stream) and re-dissolution in 0.2 mL of ultrapure water before HPLC-ICP-MS. Synthesized material was found to pre-concentrate inorganic arsenic species; whereas organic arsenic compounds, mainly arsenobetaine (the major organoarsenic compound in fish/seafood products), were not found to interact with the adsorbent. The developed selective method gave limits of quantification of 1.05 and 1.31 µg kg−1 for As (III) and As (V), respectively, and good precision [relative standard deviations lower than 12% in fish extracts spiked at several As (III) and As (V) levels]. The proposed method was finally applied to the selective determination of As (III) and As (V) species in several fishery products.This work was supported by the Dirección Xeral de I + D – Xunta de Galicia Grupos de Referencia Competitiva (project number 6RC2014/2016 and ED431C2018/19), and Development of a Strategic Grouping in Materials - AEMAT (grant ED431E2018/08). The authors also wish to thank Dr. M. José Pazos-Guldrís (Unidade de Microscopía) at Rede de Infraestruturas de Apoio á Investigación e ao Desenvolvemento Tecnolóxico – Universidade de Santiago de Compostela) SEM technical support.S

Exploiting dynamic reaction cell technology for removal of spectral interferences in the assessment of Ag, Cu, Ti, and Zn by inductively coupled plasma mass spectrometry

Analytical methods based on dynamic-reaction cell (DRC) technology using ammonia as a reaction gas have been developed for the determination of ultra-trace Ti, Zn, Cu and Ag by inductively coupled plasma mass spectrometry (ICP-MS). Challenging spectral interferences from complex matrices were demonstrated to be overcome by DRC, and several DRC approaches (on-mass and mass-shift) using ammonium (NH3) as a reaction gas were assessed and compared to the standard or “vented” mode analysis. Ammonium cluster ions were generated for Ti, Cu, Zn, and Ag (mass shift approach). The on-mass approach was also explored to take advantage of collisional focusing phenomena. In addition, DRC operating conditions were optimised by modifying NH3 gas flow rate and rejection parameter q (RPq). The optimised conditions were applied to show the usefulness of either on-mass or mass-shift approaches when removing Ca and P interferences. Finally, the sensitivity of all measurement modes was studied and excellent limits of detection (at few ng L−1 levels) were assessedThe authors wish to acknowledge the financial support of the Ministerio de Economía y Competitividad, Gobierno de España (project INNOVANANO, reference RT2018-099222-B-100), and the Xunta de Galicia (Grupo de Referencia Competitiva, grant number ED431C2018/19)S

Ionic imprinted polymer – Vortex-assisted dispersive micro-solid phase extraction for inorganic arsenic speciation in rice by HPLC-ICP-MS

This study combines ultrasound-assisted extraction and vortex-assisted dispersive micro-solid phase extraction using an ionic imprinted polymer as a selective sorbent for rapid isolation and pre-concentration of inorganic arsenic species (As(III) and As(V)) in extracts from rice samples prior to their determination by high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry. All factors affecting the ultrasound assisted extraction of the species from rice (ultrasound amplitude, sonication time and sonication mode) and their selective pre-concentration by ionic imprinted polymer-based vortex-assisted dispersive micro-solid phase extraction (sorbent amount, extract pH, vortex extraction time and speed, eluting solution and vortex elution time and speed) were optimized. The analytical performance of the procedure was studied at optimum conditions: ultrasound continuous sonication at 40% amplitude for 2.0 min using 1:1 methanol/ultrapure as an extractant, 50 mg of sorbent, extract pH at 8.0, vortex loading at 1000 rpm for 1.0 min, and elution with ultrapure water by vortexing at 1000 rpm for 1.0 min, pre-concentration procedure which leads to a pre-concentration factor of 10. The limits of detection obtained for As (III) and As (V) were 0.20 and 0.41 μg kg−1, respectively, and were well below the maximum levels established by the European Union in rice and rice containing products. The method was found to be precise (intraday and interday relative standard deviations ≤ 11%) and selective. The accuracy was confirmed by analysing the ERM-BC211 (rice, As species) certified reference material, and the method was successfully applied to commercial rice samples.The authors thank Xunta de Galicia for financial support (Grupo de Referencia Competitiva project number ED431C2018/19, and Program for the Development of the Strategic Grouping in Materials - AEMAT project number ED431E2018/08). These programs are co-funded by FEDER (UE).S

Single-particle inductively coupled plasma mass spectrometry using ammonia reaction gas as a reliable and free-interference determination of metallic nanoparticles

Intensive production of nanomaterials, especially metallic nanoparticles (MNPs), and their release into the environment pose several risks for humans and ecosystem health. Consequently, high-efficiency analytical methodologies are required for control and characterization of these emerging pollutants. Single-particle inductively coupled plasma – mass spectrometry (SP-ICP-MS) is a promising technique which allows the determination and characterization of MNPs. However, several elements or isotopes are hampered by spectral interferences, and dynamic-reaction cell (DRC) technology is becoming a useful tool for free interference determination by ICP-MS. DRC-based SP-ICP-MS methods using ammonia as a reaction gas (either on-mass approach or mass-shift approaches) have been developed for determining titanium dioxide nanoparticles (TiO2 NPs), copper oxide nanoparticles (CuO NPs), copper nanoparticles (Cu NPs), and zinc oxide nanoparticles (ZnO NPs). The effects of parameters such as ammonia flow rate and dwell time on the peak width (NP transient signal in SP-ICP-MS) were comprehensively studied. Influence of NP size and nature were also investigateThe authors wish to acknowledge the financial support of the Ministerio de Economía y Competitividad (INNOVANANO projects, reference RT2018-099222-B-100), and the Xunta de Galicia (Grupo de Referencia Competitiva, grant number ED431C2018/19)S

Synthesis and application of a surface ionic imprinting polymer on silicacoated Mn-doped ZnS quantum dots as a chemosensor for the selective quantification of inorganic arsenic in fish

This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: https://doi.org/10.1007/s00216-020-02405-1A novel room temperature phosphorescence chemosensor probe has been successfully developed and applied to the selective detection and quantification of inorganic arsenic (As(III) plus As(V)) in fish samples. The prepared material (IIP@ZnS:Mn QDs) was based on Mn-doped ZnS quantum dots coated with (3-aminopropyl) triethoxysilane and an As(III) ionic imprinted polymer. The novel use of vinyl imidazole as a complexing reagent when synthesizing the ionic imprinted polymer guarantees that both inorganic arsenic species (As(III) and As(V)) can interact with the recognition cavities in the ionic imprinted polymer. After characterization, several studies were performed to enhance the interaction between the targets (As(III) and As(V) ions) and the IIP@ZnS:Mn QDs nanoparticles. The optimization and validation process showed that the composite material offers high selectivity (high imprinting factor) for inorganic arsenic species. The limit of quantification for total inorganic As was 29.6 μg kg-1, value lower than the EU/EC regulation limits proposed for other foodstuffs than fish, such as rice. The proposed method is therefore simple, requires short analysis times and offers good sensitivity, precision (inter-day relative standard deviations lower than 10%), and quantitative analytical recoveries. The method has been successfully applied to assess total inorganic arsenic in several fishery products, showing good agreement with the total inorganic arsenic concentration (As(III) plus As(V)) found after applying other advanced and expensive methods such those based on high performance liquid chromatography hyphenated to inductively coupled plasma – mass spectrometryThis work was supported by the Dirección Xeral de I+D – Xunta de Galicia Grupos de Referencia Competitiva (project number 6RC2014/2016 and ED431C2018/19), and Development of a Strategic Grouping in Materials - AEMAT (grant ED431E2018/08). Authors thanks to Dr. Bruno Dacuña-Mariño (Unidade de Raios X) at Rede de Infraestruturas de Apoio á Investigación e ao Desenvolvemento Tecnolóxico – University of Santiago de Compostela) for XRD technical support, to Eugenio Solla (Servicio de Microscopía Electrónica) at CACTI– University of Vigo for TEM/EDS technical support, and to Dr. María Celeiro (LIDSA, Department of Analytical Chemistry, Nutrition and Bromatology – University of Santiago de Compostela) for ASE technical assistance.S

Mercury speciation in edible seaweed by liquid chromatography - Inductively coupled plasma mass spectrometry after ionic imprinted polymer-solid phase extraction

In contrast to most of essential and heavy metals, mercury levels in seaweed are very low, and pre-concentration methods are required for an adequate total mercury determination and mercury speciation in this foodstuff. An ionic imprinted polymer-based solid phase extraction (on column) pre-concentration procedure has been optimized for mercury species enrichment before liquid chromatography hyphenated with inductively coupled plasma mass spectrometry determination. The polymer has been synthesized by the precipitation polymerization method and using a ternary pre-polymerization mixture containing the template (methylmercury), a non-vinylated monomer (phenobarbital), and a vinylated monomer (methacrylic acid). Factors affecting the adsorption/desorption of Hg species (extract pH, loading and elution flow rates, volume of eluent, etc.), and parameters such as breakthrough volume and reusability, were fully studied. Mercury species were first isolated from seaweed by ultrasound assisted extraction using a 0.1% (v/v) HCl, 0.12% (w/v) l-cysteine, 0.1% (v/v) mercaptoethanol solution. Under optimized conditions, the limits of detection were 0.007 and 0.02 μg kg−1 dw for methylmercury and Hg(II), respectively. The pre-concentration factor (volume of 10 mL of seaweed extract) was 50. Repeatability and reproducibility of the method were satisfactory with relative standard deviations lower than 16%. The proposed methodology was finally applied for the selective pre-concentration and determination of methylmercury and Hg (II) in a BCR-463 certified reference material and in several edible seaweeds.This work was supported by the Dirección Xeral de I + D –Xunta de Galicia: Grupos de Referencia Competitiva, project number ED431C2018/19; and Development of a Strategic Grouping in Materials – AEMAT, grant ED431E2018/08.S

Cloud point extraction and ICP-MS for titanium speciation in water samples

An analytical method for the separation and determination of titanium dioxide nanoparticles in water samples has been developed. The separation was performed by Cloud Point Extraction (CPE) with Triton X-114. Titanium dioxide nanoparticles and ionic titanium were analysed in the surfactant rich phase and surfactant poor phase respectively, by inductively coupled plasma-mass spectrometry (ICP-MS). Parameters related to the CPE procedure such as Triton X-114 and NaCl concentrations were evaluated. Optimum concentrations of 0.03% (w/v) and 2.5 mM of Triton X-114 and NaCl respectively, were selected to develop this study. The TiO2 nanoparticles extracted were digested using HNO3 and H2O2 in an ultrasonic bath for 10 min at 60°C and analysed by ICP-MS. The analytical characteristics of the method (calibration, limits of detection and quantification, precision and recovery) were evaluated. The LOD and LOQ for Ti determination in the surfactant rich phase were 0.13 and 0.45 µg L−1, respectively. Finally, the method was applied for the determination of TiO2 nanoparticles in swimming pool water samplesThe authors wish to thank the Spanish Ministerio de Ciencia, Innovación y Universidades (Project number RTI2018-099222-B-100), the European Union (programme Interreg Atlantic Area, Project number EAPA_590/2018), and Xunta de Galicia (Grupo de Referencia Competitiva ED431C2018/19 for financial support. This research was partially supported by the Consellería de Educación Program for the Development of Strategic Grouping in Materials - AEMAT at the University of Santiago de Compostela under grant No. ED431E2018/08, Xunta de Galicia. These programs are co-funded by FEDER (UE).S

Experimental and Computational Studies on the Interaction of a Dansyl-Based Fluorescent Schiff Base Ligand with Cu2+ Ions and CuO NPs

We studied the interaction of Cu2+ ions and CuO nanoparticles with the fluorescent Schiff base ligand H3L, which derives from the condensation of 4-formyl-3-hydroxybenzoic acid with N-(2-aminobenzyl)-5-(dimethylamino)naphthalene-1-sulfonamide (DsA). A detailed assignment of the most significant bands of the electronic and infrared spectra of H3L and DsA was performed using DFT methods, based on both crystal structures. The affinity of H3L to react with Cu2+ ions in solution (KB = 9.01 103 L mol-1) is similar to that found for the Cu2+ ions present on the surface of CuO NPs (KB = 9.84 103 L mol-1). Fluorescence spectroscopic measurements suggest five binding sites for H3L on the surface of the CuO NPs used. The µ-XRF analysis indicates that a polycrystalline sample of CuO-H3L NPs contains 15:1 Cu:S molar ratio (CuO:H3L). ATR-FTIR spectroscopy, supported by DFT calculations, showed that the HL2- (as a phenolate and sulfonamide anion) is coordinated to superficial Cu2+ ions of the CuO NPs through their azomethine, sulphonamide, and phenolic groups. A solution of H3L (126 ppb) shows sensitive responses to CuO NPs, with a limit of detection (LOD) of 330 ppb. The working range for detection of CuO NPs with [H3L] = 126 ppb was 1.1-9.5 ppm. Common metal ions in water, such as Na+, K+, Mg2+, Ca2+, Fe3+, and Al3+ species, do not interfere significantly with the detection of CuO NPs.This research was funded by the Ministerio de Ciencia, Innovación y Universidades (RTI2018-099222-B-I00) and Interreg Atlantic Area, Poctep (ACUINANO Project). Authors would like to thank the use of RIAIDT-USC analytical facilities, and the support provided for this work.S

Development of a micro-solid-phase extraction molecularly imprinted polymer technique for synthetic cannabinoids assessment in urine followed by liquid chromatography–tandem mass spectrometry

Several molecularly imprinted polymers (MIPs) have been synthesized for the first time using various synthetic cannabinoids (JWH007, JWH015 and JWH098) as template molecules. Ethylene dimethacrylate (EDMA) was used as a functional monomer for all cases. Similarly, divinylbenzene (DVB) and 2,2′-azobisisobutyronitrile (AIBN) were used as cross-linker and initiator, respectively. The prepared MIPs have been fully characterized and evaluated as new selective adsorbents for micro-solid phase extraction (μ-SPE) of synthetic cannabinoids in urine. The developed MIP-μ-SPE devices consisted of a polypropylene (PP) porous membrane containing the adsorbent (novel porous membrane protected micro-solid phase extraction based on a cone-shaped device) for operating in batch mode, which allowed a fast and integrated extraction-cleanup procedure. High performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) was used for quantifying the analytes after MIP-μ-SPE. The best performances were obtained for MIPs prepared from JWH015 as a template. Optimum loading conditions were found to be urine pH of 5.0 and adsorption time of 8.0 min under mechanical (orbital-horizontal) stirring at 100 rpm. The composition of the eluting solution consisted of 75:20:5 heptane/2-propanol/ammonium hydroxide. The elution was assisted by ultrasounds (37 kHz, 325 W) for 8.0 min. In addition, studies regarding selectivity have also been addressed for several drugs of abuse under optimized loading/adsorption conditions. Validation of the method showed good precision and analytical recovery by intra-day and inter-day assays (RSD values lower than 7 and 10% for intra-day and inter-day precision, and within the 83–100% range for intra-day and inter-day analytical recovery)

Analysis of brain regional distribution of aluminium in rats via oral and intraperitoneal administration

In the present work, accumulation and distribution of aluminium in the rat brain following both intraperitoneal and oral administration were studied. Electrothermal atomic absorption spectrometry was used to determine aluminium concentration in different brain areas (cerebellum, ventral midbrain, cortex, hippocampus, and striatum). Most of the brain areas showed accumulation of aluminium, but a greater and more significant increase was noted in the group receiving aluminium via intraperitoneal administration. Aluminium distribution was also dependent on the administration route.S