Study of silver nanoparticles bioaccumulation in cultured red and green seaweed.

The bioaccumulation of polyvinylpyrrolidone-coated silver nanoparticles (PVP-AgNPs) in Palmaria palmata and Ulva sp. seaweed was investigated by ICP-MS and SP-ICP-MS (determination of nanoparticles and size distribution after an enzymatic extraction). Seaweeds were exposed to 0.

Bioaccumulation of titanium dioxide nanoparticles in green (Ulva sp.) and red (Palmaria palmata) seaweed.

A bioaccumulation study in red (Palmaria palmata) and green (Ulva sp.) seaweed has been carried out after exposure to different concentrations of citrate-coated titanium dioxide nanoparticles (5 and 25 nm) for 28 days. The concentration of total titanium and the number and size of accumulated nanoparticles in the seaweeds has been determined throughout the study by inductively coupled plasma mass spectrometry (ICP-MS) and single particle-ICP-MS (SP-ICP-MS), respectively.

Proteomics reveals multiple effects of titanium dioxide and silver nanoparticles in the metabolism of turbot, Scophthalmus maximus.

Titanium dioxide (TiO) and silver (Ag) NPs are among the most used engineered inorganic nanoparticles (NPs); however, their potential effects to marine demersal fish species, are not fully understood. Therefore, this study aimed to assess the proteomic alterations induced by sub-lethal concentrations citrate-coated 25 nm ("P25") TiO or polyvinylpyrrolidone (PVP) coated 15 nm Ag NPs to turbot, Scophthalmus maximus. Juvenile fish were exposed to the NPs through daily feeding for 14 days.

Ultrasonication followed by enzymatic hydrolysis as a sample pre-treatment for the determination of Ag nanoparticles in edible seaweed by SP-ICP-MS.

Seaweed can bioaccumulate nanomaterials that would be transferred to the trophic chain. This work describes the optimization of a method for the separation of silver nanoparticles (AgNPs) from seaweed using an ultrasound-assisted enzymatic hydrolysis method and ulterior determination by single particle inductively coupled plasma mass spectrometry (SP-ICP-MS). The following parameters affecting the isolation of AgNPs were optimized using a Palmaria palmata (red seaweed) sample previously exposed to AgNPs: type of sonication (bath vs.

Titanium dioxide nanoparticles assessment in seaweeds by single particle inductively coupled plasma - Mass spectrometry.

In this study, a first attempt for isolating and determining (characterising) background levels of titanium dioxide nanoparticles (TiO NPs) in seaweed has been developed by using single particle inductively coupled plasma - mass spectrometry (SP-ICP-MS). Seaweeds were processed using an optimised ultrasound assisted extraction (UAE) procedure based on tetramethylammonium hydroxide (TMAH) before dilution and SP-ICP-MS analysis. The effect of the TMAH percentage in the extracting solution, as well as the volume of extracting solution and sonication (extraction) time, has been fully assessed.

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).

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.

A phenobarbital containing polymer/ silica coated quantum dot composite for the selective recognition of mercury species in fish samples using a room temperature phosphorescence quenching assay.

An analytical procedure using low-cost instrumentation (fluorescence/phosphorescence spectrophotometer) has been developed to assess total mercury in fishery products. Determinations were based on the room temperature phosphorescence (RTP) quenching of a composite Ph-QDs consisting of phenobarbital-containing polymer/silica coated Mn-doped ZnS quantum dots. Under optimum conditions (fish extract pH of 8.

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.

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

A 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.

Simultaneous determination and speciation analysis of arsenic and chromium in iron supplements used for iron-deficiency anemia treatment by HPLC-ICP-MS.

This work proposes the use of high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC-ICP-MS) for simultaneous speciation of arsenic and chromium in iron supplements used for the treatment of anemia. The sample preparation procedure recommended for the total determination of arsenic and chromium was established using acid digestion in a microwave assisted oven. For speciation analysis, however, the microwave-assisted extraction procedure involved the use of water as extraction solvent at 90°C for 30min.

Evaluation of number concentration quantification by single-particle inductively coupled plasma mass spectrometry: microsecond vs. millisecond dwell times.

The quality of the quantitative information in single-particle inductively coupled plasma mass spectrometry (SP-ICP-MS) depends directly on the number concentration of the nanoparticles in the sample analyzed, which is proportional to the flux of nanoparticles through the plasma. Particle number concentrations must be selected in accordance with the data acquisition frequency, to control the precision from counting statistics and the bias, which is produced by the occurrence of multiple-particle events recorded as single-particle events. With quadrupole mass spectrometers, the frequency of data acquisition is directly controlled by the dwell time.

Simple and Sensitive Molecularly Imprinted Polymer - Mn-Doped ZnS Quantum Dots Based Fluorescence Probe for Cocaine and Metabolites Determination in Urine.

A new molecularly imprinted polymer (MIP)-based fluorescent artificial receptor has been prepared by anchoring a selective MIP for cocaine (COC) on the surface of polyethylene glycol (PEG) modified Mn-doped ZnS quantum dots (QDs). The prepared material combines the high selectivity attributed to MIPs and the sensitive fluorescent property of the Mn-doped ZnS QDs. Simple and low cost methods have therefore been optimized for assessing cocaine abuse in urine by monitoring the fluorescence quenching when the template (COC) and also metabolites from COC [benzoylecgonine (BZE) and ecgonine methyl ester (EME)] are present.

Synthesis of an imprinted polymer for the determination of methylmercury in marine products.

A molecularly imprinted polymer was synthesized using the precipitation method with methylmercury chloride as the template, phenobarbital as ligand, methacrylic acid (MMA) as monomer, and ethylene glycoldimethacrylate (EDMA) as cross-linking agent. The MIP was characterized using elemental analysis, infrared spectroscopy, energy dispersive X-ray fluorescence and scanning electron microscopy. The operating conditions for solid phase extraction (SPE) were optimized in column mode (pH, loading and elution flow rate using 1M thiourea in 1M HCl).

Synthesis and characterization of novel molecularly imprinted polymer - coated Mn-doped ZnS quantum dots for specific fluorescent recognition of cocaine.

Mn-doped ZnS quantum dots (QDs) coated with a molecularly imprinted polymer (MIP) material selective toward cocaine and its metabolites have been prepared and applied to cocaine (COC) and metabolites assessment by spectrofluorimetry. Ultrasound irradiation (37kHz) was novelty used for performing the Mn-doped ZnS QDs synthesis as well as for preparing the QD based MIP-coated composite by precipitation polymerization (imprinting process). This fact allowed the synthesis to be accomplished in four hours.

Mercury speciation in seawater by liquid chromatography-inductively coupled plasma-mass spectrometry following solid phase extraction pre-concentration by using an ionic imprinted polymer based on methyl-mercury-phenobarbital interaction.

Trace levels of inorganic mercury, methyl-mercury and ethyl-mercury have been assessed in seawater by high performance liquid chromatography (HPLC) hyphenated with inductively coupled plasma-mass spectrometry (ICP-MS) after solid phase extraction (SPE) pre-concentration with a novel synthesized ionic imprinted polymer. The adsorbent material was prepared by trapping a non-vinylated chelating ligand (phenobarbital) via imprinting of a ternary mixed ligand complex of the non-vinylated chelating agent, the template (methyl-mercury), and the vinyl ligand (metacrylic acid, MAA). Ethylene dimetacrylate (EDMA) and 2,2'-azobisisobutyronitrile (AIBN) were used as cross-linker and initiator reagents, respectively; and the precipitation polymerization technique was used in a porogen of acetonitrile/water (4:1).

Two-dimensional isoelectric focusing OFFGEL and microfluidic lab-on-chip electrophoresis for assessing dissolved proteins in seawater.

Dissolved proteins were assessed in surface and deep seawater by two-dimensional isoelectric focusing (IEF) OFFGEL-lab-on-chip (LOC) electrophoresis after tangential flow ultrafiltration followed by centrifugal ultrafiltration (preconcentration factor of 3000). Dissolved protein isolation was performed by treating the ultrafiltrated retentate with cold acetone and also with chloroform as precipitating reagents. The best electrophoretic behavior of the isolated proteins was obtained after protein precipitation with chloroform before different rinsing stages for removing methanol and water interferences.

Analytical performance of a lab-made concomitant metal analyzer to generate volatile species of Ag, Au, Cd, Cu, Ni, Sn and Zn using 8-hydroxyquinoline as a reaction media.

This study evaluated the main parameters affecting Ag, Au, Cd, Cu, Ni, Sn and Zn vapor generation using a lab-made concomitant metal analyzer (CMA) as a reaction chamber and gas-liquid separator. The modifier used in the reaction media was 8-hydroxyquinoline, and Inductively-Coupled Plasma Optical Emission Spectrometry was used as detection technique. The performance of the lab-made concomitant analyzer was compared with the performance of a continuous flow gas-liquid separator and of a cyclonic spray chamber.

Comparison of two lab-made spray chambers based on MSIS™ for simultaneous metal determination using vapor generation-inductively coupled plasma optical emission spectroscopy.

The objective of this study is to evaluate the performance of two lab-made systems based on the Multimode Introduction System (MSIS™) and the modified MSIS™, to generate and introduce vapors of Ag, Cu, Cd, Cu, Ni, Sn, Zn, and also Au in the ICP torch. An univariate procedure was used to select the optimized working conditions (Ar flow, sample, reductant and waste flows, and reagent concentrations). Optimum conditions for working with modified MSIS were: nitric acid concentration 0.

Development of a microalgal PAM test method for Cu(II) in waters: comparison of using spectrofluorometry.

Test methods are needed to monitor Cu concentrations in reservoirs and water supplies. Dictyosphaerium chlorelloides (Chlorophyta) cells were immobilized in a silicate sol-gel and the toxic effects of Cu(II) were examined using different techniques: fluorescence measurements (using a spectrofluorometer with an optic fiber coupled to a flow cell or a 96-well-plate reader) or by Pulse Amplitude Modulation (PAM) parameters using a portable instrument and the pulse saturation method. Fm' and qN were the most sensitive indicator parameters when performing Cu analysis in water.

On-line ionic imprinted polymer selective solid-phase extraction of nickel and lead from seawater and their determination by inductively coupled plasma-optical emission spectrometry.

Nickel(II) and lead(II) ionic imprinted 8-hydroxyquinoline polymers were synthesized by a precipitation polymerization technique and were used as selective solid phase extraction supports for the determination of nickel and lead in seawater by flow injection solid phase extraction on-line inductively coupled plasma-optical emission spectrometry. An optimum loading flow rate of 2.25 mL min(-1) for 2 min and an elution flow rate of 2.

Matrix solid-phase dispersion as a sample pretreatment for the speciation of arsenic in seafood products.

Matrix solid-phase dispersion (MSPD) has been applied to extract arsenical species (arsenite, As(III); arsenate, As(V); monomethylarsonic acid; dimethylarsinic acid, DMA; arsenobetaine, AsB; and arsenocholine) from seafood products. High-performance liquid chromatography coupled to inductively coupled plasma-mass spectrometry was used to separate and detect all arsenic species. Variables affecting MSPD, such as the solid support material (dispersing agent), solid support mass/sample mass ratio, elution solvent composition, and elution solvent volume, have been fully evaluated.

Microalgae fiber optic biosensors for herbicide monitoring using sol-gel technology.

Three microalgal species (Dictyosphaerium chlorelloides (D.c.), Scenedesmus intermedius (S.

Characterization of estuarine sediments by near infrared diffuse reflectance spectroscopy.

It has been developed a partial least squares near infrared (PLS-NIR) method for the determination of estuarine sediment physicochemical parameters. The method was based on the chemometric treatment of first order derivative reflectance spectra obtained from samples previously lyophilized and sieved through a lower than 63 microm grid. Spectra were scanned from 833 to 2976 nm, averaging 36 scans per spectrum at a resolution of 8 cm(-1), using chromatographic glass vials of 9.

Phthalates determination in physiological saline solutions by HPLC-ES-MS.

Phthalates are a group of chemical compounds with increasing interest from the analytical point of view. The risks for human health associated with some of these compounds have unleashed the necessity to develop analytical methods with great sensitivity that allow us to detect their presence at trace levels in order to assure protection for the population. A simple and rapid method for determining a group of phthalate esters in aqueous samples was developed.