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This study investigates spatio-temporal variations of PM10 mass concentrations and associated metal(oid)s, δ13C carbon isotope ratios, polycyclic aromatic hydrocarbons (PAHs), total organic carbon (TOC) and equivalent black carbon (eBC) concentrations over a half year period (from March 2017 to October 2017) in two residential areas of Medellín (MED-1 and MED-2) and Itagüí municipality (ITA-1 and ITA-2) at a tropical narrow valley (Aburrá Valley, Colombia), where few data are available. A total of 104 samples were analysed by using validated analytical methodologies, providing valuable data for PM10 chemical characterisation. Metal(oid)s concentrations were measured by inductively coupled plasma mass spectrometry (ICP-MS) after acid digestion, and PAHs concentrations were measured by Gas Chromatography-Mass Spectrometry (GC–MS) after Pressurised Hot Water Extraction (PHWE) and Membrane Assisted Solvent Extraction (MASE). Mean PM10 mass concentration ranged from 37.0 µg m−3 to 45.7 µg m−3 in ITA-2 and MED-2 sites, respectively. Al, Ca, Mg and Na (from 6249 ng m−3 for Mg at MED-1 site to 10,506 ng m−3 for Ca at MED-2 site) were the major elements in PM10 samples, whilst As, Be, Bi, Co, Cs, Li, Ni, Sb, Se, Tl and V were found at trace levels (< 5.4 ng m−3). Benzo[g,h,i] perylene (BghiP), benzo[b + j]fluoranthene (BbjF) and indene(1,2,3-c,d)pyrene (IcdP) were the most profuse PAHs in PM10 samples, with average concentrations of 0.82–0.86, 0.60–0.78 and 0.47–0.58 ng m−3, respectively. Results observed in the four sampling sites showed a similar dispersion pattern of pollutants, with temporal fluctuations which seems to be associated to the meteorology of the valley. A PM source apportionment study were carried out by using the positive matrix factorization (PMF) model, pointing to re-suspended dust, combustion processes, quarry activity and secondary aerosols as PM10 sources in the study area. Among them, combustion was the major PM10 contribution (accounting from 32.1 to 32.9% in ITA-1 and ITA-2, respectively), followed by secondary aerosols (accounting for 13.2% and 23.3% ITA-1 and MED-1, respectively). Finally, a moderate carcinogenic risk was observed for PM10-bound PAHs exposure via inhalation, whereas significant carcinogenic risk was estimated for carcinogenic metal(oid)s exposure in the area during the sampling period. [ABSTRACT FROM AUTHOR] more...

A novel in-vitro method, by using synthetic body fluids, human physiological conditions and a simulated air-blood barrier (by using a dialysis membrane) has been developed and applied to assess in-vitro inhalation bioavailability of metal(oid)s associated to particulate matter (PM 2,5) samples collected from an industrial site of the Northwest of Spain. A validated analytical methodology based on inductively coupled plasma mass spectrometry (ICP-MS) was used to analyse metal(oid)s concentrations in bioavailable fractions. This approach would be a more realistic human health risk assessment since considering processes that occur in human body in contrast the overestimation derived from current models (which consider environmental concentrations). Metal(oid)s such as Cu and Mo seemed to be the most bioavailable (mean in-vitro bioavailability ratios higher than 70%); Ba, Cd, Mn, Pb, Rb, Sb, Sn, V and Zn shown mean ratios between 20 and 60%, while low in-vitro bioavailability ratios (less than 20%) were observed for metal(oid)s such as Al, Co, Cr, Fe, Ni, Ti, and Tl. Health risk assessment via inhalation based on hazard carcinogenic and non-carcinogenic indexes (HI c and HI nc , respectively) were performed considering three exposure scenarios using both inhalation bioavailable and total metal(oid)s concentrations in PM 2.5 samples, suggesting no risk to human health. The influence of chemical composition on in-vitro bioavailability ratios was obtained, pointing out that inhalation ratios of Al, Ba, Cr, Cu, Fe, Ni, Pb and V seem to be affected by sea salt and/or crustal and/or biogenic and/or anthropogenic content of PM 2.5. [Display omitted] • Bioavailability of metal(oid)s was estimated by a simulated dialysis approach. • High inhalation bioavailability ratios (>70%) were found for Cu and Mo. • Low bioavailability ratios (<20%) were found for Al, Co, Cr, Fe, Ni, Ti and Tl. • Bioavailability of some metal(oid)s seemed to be correlated with PM 2.5 compositions. • Health risks for PM 2.5 -bound metal(oid)s via inhalation suggesting no risk to human. [ABSTRACT FROM AUTHOR] more...

An analytical method has been developed for determination of major (Ca, K, Mg, and Na) and trace elements (As, Cd, Co, Li, Ni, and Sr) in human scalp hair. The proposed method includes a novel, simple, rapid, highly efficient, and automated metal-leaching procedure, by pressurized-liquid extraction (PLE), combined with a rapid simultaneous detection system—inductively coupled plasma–optical-emission spectrometry (ICP–OES). PLE is one of the most promising recently introduced sample-preparation techniques, with the advantages of reducing solvent consumption and enabling automated sample handling. The operating conditions for PLE, including concentration of the extraction solvent, extraction temperature, static time, number of extraction steps, pressure, mean particle size, diatomaceous earth (DE) mass/sample mass ratio, and flush volume were studied using an experimental design (Plackett–Burman design, PBD). The optimum conditions were use of 0.75 mol L−1 acetic acid as extracting solution and powdered hair samples thoroughly mixed with DE, as a dispersing agent, at a DE mass/sample mass ratio of 4. Extraction was performed at room temperature and an extraction pressure of 140 atm for 5 min in one extraction step. The flush volume was fixed at 60%. The PLE-assisted multi-element leaching proposed is complete after 7 min (5 min static time plus 1 min purge time plus 1 min end relief time). Under the optimised conditions the figures of merit, for example limits of detection and quantification, repeatability of the over-all procedure, and accuracy, were evaluated. Analysis of GBW-07601 (human hair) certified reference material revealed accuracy was good for the target elements. The optimised method was finally applied to several human scalp-hair samples. [ABSTRACT FROM AUTHOR] more...

The use of pressurised solvents (liquids at a high pressure and/or high temperature without reaching the sub–critical point) or microwave energy were investigated to accelerate enzymatic hydrolysis processes of selected foods (Brazil nut, golden berries, acai fruit and heart of palm) from Amazon region for multi–element determinations. The target elements (Ca, Co, Cu, K, Mg, Ni, P and Rb) were released from dried and defatted foods by the action of a protease and an enzyme activator (DTT, dithiothreitol), and they have been evaluated by inductively coupled plasma – mass spectrometry (ICP–MS). The influence of variables inherent to the enzymatic activity (TRIS-HCl concentration, TRIS-HCl volume, pH, temperature, and protease XIV and DTT masses) and factors affecting pressurisation and/or microwave extraction (pressurised time, pressure and microwave extraction steps) on the efficiency of metals leaching were evaluated using a Plackett-Burman 2 8 × 3/32 experimental design as screening method. Results shown statistical significance for extraction temperature and TRIS-HCl concentration (confidence interval of 95%) for enzymatic extraction assisted by solvent pressurisation, whereas number of microwave extraction steps and DTT mass have affected enzymatic extraction assisted by microwave energy. After significant variables optimization, extraction procedure times were 7 min (7 min per sample) and 70 min (12 min per sample) for enzymatic extraction assisted by pressurisation and microwave energy, respectively. Limits of quantification were found to be from 1.2 ng g − 1 to 53.8 μg g − 1 and 0.23 ng g − 1 to 35.1 μg g − 1 for enzymatic extraction assisted by pressurisation and microwave energy, respectively. Repeatability of the over–all procedures were generally below 20%. Element contents in Amazon samples were within the 80–1400, 0.03–3.0, < 0.58–50, 500–25,000, 60–7480, 0.40–11.0, 70–14,000, 0.4–200 μg g − 1 ranges for Ca, Co, Cu, K, Mg Ni, P and Rb, respectively. [ABSTRACT FROM AUTHOR] more...

Abstract: In vitro bioavailability of total selenium and selenium species from different raw seafood has been assessed by using a simulated gastric and intestinal digestion/dialysis method. Inductively coupled plasma-mass spectrometry (ICP-MS) was used to assess total selenium contents after a microwave assisted acid digestion, and also to quantify total selenium in the dialyzable and non-dialyzable fractions. Selenium speciation in the dialyzates was assessed by high performance liquid chromatography (HPLC) coupled with ICP-MS detection. Major Se species (selenium methionine and oxidized selenium methionine) from dialyzate were identified and characterized by HPLC coupled to mass spectrometry (HPLC–MS). Selenocystine was detected at low concentrations while Se-(Methyl)selenocysteine and inorganic selenium species (selenite and selenate) were not detected in the dialyzate. Low bioavailability percentages for total selenium (6.69±3.39 and 5.45±2.44% for fish and mollusk samples, respectively) were obtained. Similar bioavailability percentages was achieved for total selenium as a sum of selenium species (selenocystine plus oxidized selenium methionine and selenium methionine, mainly). HPLC–MS data confirmed SeMet oxidation during the in vitro procedure. [Copyright &y& Elsevier] more...

Abstract: In-vitro bioavailability of Se has been assessed in different raw seafood and edible seaweed samples by using a simulated gastric and intestinal digestion/dialysis method. Correlations between Se bioavailability and food nutrients content have also been established. Low dialyzability percentages of Se have been found for fish and mollusk samples (6.7±3.4 and 5.5±2.4%, respectively). However, high dialyzability percentages (within the 66.7±31.1% range) have been found for seaweed. Se bioavailability exhibits a positive correlation with the carbohydrate content and with the dietary fiber. Negative correlation was obtained with the protein content. Finally, no correlation has been observed between the bio-available fraction of Se and the fat content of the studied samples. [Copyright &y& Elsevier] more...

Abstract: Analytical methods for the determination of total arsenic and arsenic species (mainly As(III) and As(V)) in human scalp hair have been developed. Inductively coupled plasma-mass spectrometry (ICP-MS) and high performance liquid chromatography (HPLC) coupled to ICP-MS have been used for total arsenic and arsenic species determination, respectively. The proposed methods include a “green”, fast, high efficient and automated species leaching procedure by pressurized hot water extraction (PHWE). The operating parameters for PHWE including modifier concentration, extraction temperature, static time, extraction steps, pressure, mean particle size, diatomaceous earth (DE) mass/sample mass ratio and flush volume were studied using design of experiments (Plackett–Burman design PBD). Optimum condition implies a modifier concentration (acetic acid) of 150mM and powdered hair samples fully mixed with diatomaceous earth (DE) as a dispersing agent at a DE mass/sample mass ratio of 5. The extraction has been carried out at 100°C and at an extraction pressure of 1500psi for 5min in four extraction step. Under optimised conditions, limits of quantification of 7.0, 6.3 and 50.3ngg−1 for total As, As(III) and As(V), respectively were achieved. Repeatability of the overall procedure (4.4, 7.2 and 2.1% for total As, As(III) and As(V), respectively) was achieved. The analysis of GBW-07601 (human hair) certified reference material was used for validation. The optimised method has been finally applied to several human scalp hair samples. [Copyright &y& Elsevier] more...

Abstract: The feasibility of pressurized hot water extraction (PHWE) has been novelty investigated to speed up water soluble halide species (bromide, Br−; bromate, BrO3 −; iodide, I− and iodate, IO3 −) leaching from atmospheric particulate matter (PM10 and PM2.5). Total bromine and iodine and total water soluble bromine and iodine have been assessed by inductively coupled plasma—mass spectrometry (ICP–MS). Water-soluble bromine and iodine species were also measured by ICP–MS after anion exchange high performance liquid chromatography (HPLC). Variables inherent to the pressurized hot water extraction process (temperature, modifier concentration, static time, pressure, number of cycles and dispersing agent mass) were fully studied. Results showed that the pressurized leaching procedure can be performed in 9min (5min for pre-heating, 2min of static time, 1min of purge time, and 1min of end relief time). The use of diluted acetic acid as a modifier did not improve the target recoveries. Dispersing agent (diatomaceous earth) was not needed, which reduces the time for filling the cells. Water-soluble halides were reached under the following extraction conditions: extraction temperature of 100°C, pressure of 1500psi, static time of 2min and 1 extraction cycle. Optimized HPLC conditions consisted of an isocratic elution with 175mM ammonium nitrate plus 15% (v/v) methanol as mobile phase (optimum flow rate of at 1.5mLmin−1). Analytical performances, such as limits of detection and quantification, repeatability and analytical recoveries of the over-all procedure have been established. Results obtained show water soluble halides accounted for approximately 20.9±1.3 and 11.8±0.6% of the total bromine and total iodine, respectively. A 79 and 89% of bromine and iodine was non-water soluble, which may be organic non-water soluble species. Br− and IO3 − were found to be the major species, and they accounted for 100% of the total water-soluble bromine and iodine. [Copyright &y& Elsevier] more...

Abstract: A simulated in vitro digestion method for the dialyzability assessment of trace metals (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, V and Zn) from different seafood and edible seaweed has been developed. Inductively coupled plasma-mass spectrometry was used for metal determination in the dialyzates and in the samples after a microwave assisted acid digestion pre-treatment. Trueness of the procedure for total metal determination has been assessed by analyzing different certified reference materials (DORM-2, BCR 279 and NIES-09); whereas, trueness for the in vitro bioavailability method has been established after performing a mass balance study. Low (2.6–10.8%) and moderate (21.5–41.3%) dialyzability percentages have been found in seafood samples. However, high dialyzability percentages (30.0–74.7%) have been found in edible seaweeds. Linear and quadratic models have shown that the bioavailability of some metals exhibited good positive correlation with the carbohydrate content and also with the dietary fibre level. Protein content showed good negative correlation with the bioavailability of certain metals, whereas, moderate negative correlation was found with fat content. [Copyright &y& Elsevier] more...

Abstract: Enzymatic hydrolysis of seafood materials for isolating arsenic species (As(III), As(V), DMA and AsB) has been successfully performed by assisting the procedure with ultrasound energy (35kHz) supplied by an ultrasound water-bath. The use of pepsin, as a proteolytic enzyme, under optimized operating conditions (pH 3.0, temperature 40°C, enzyme to sample ratio of 0.3) led to an efficient assistance of the enzymatic process in a short period of time (from 4.0 to 30min). The enzymatic extract was then subjected to a clean-up procedure based on ENVI-Carb™ solid phase extraction (SPE). An optimized anion exchange high performance liquid chromatography (HPLC) coupled to inductively coupled plasma-mass spectrometry (ICP-MS) permitted the fast separation (less than 15min) of six different arsenic species (arsenite, As(III); arsenate, As(V); dimethylarsinic acid, DMA; and arsenobetaine, AsB; as well as monomethylarsonic acid, MMA; and arsenocholine, AsC) in a single run. Relative standard deviations (n =11) of the over-all procedure were 7% for AsB and DMA, 11% for As(III) and 9% for MMA. HPLC–ICP-MS determinations were performed using aqueous calibrations covering arsenic concentrations of 0, 5, 10, 25, 100 and 200μgL−1 (expressed as arsenic) for As(III), As(V), MMA, DMA and AsC; and 0, 125, 250, 500, 750, 1000 and 2000μgL−1 (expressed as arsenic) for AsB. Germanium (5μgL−1) was used as an internal standard. Analytical recoveries from the anion exchange column varied from 96 to 105% (enzymatic digests spiked with low target concentrations), from 97 to 104% (enzymatic digests spiked with intermediate target concentrations), and from 98 to 103% (enzymatic digests spiked with high target concentrations). The developed method was successfully applied to two certified reference materials (CRMs), DORM-2 and BCR 627, which offer certified AsB and DMA contents, and also to different seafood samples (mollusks, white fish and cold water fish). Good agreement between certified and found AsB concentrations was achieved when analyzing both CRMs; and also, between certified and found DMA concentrations in BCR 627. In addition, the sum of the different arsenic species concentrations found in most of the analyzed samples was statistically similar to the assessed total arsenic concentrations after a total sample matrix decomposition treatment. [Copyright &y& Elsevier] more...

Abstract: The feasibility of pressurized conditions to assist enzymatic hydrolysis of seafood tissues for arsenic speciation was novelty studied. A simultaneous in situ (in cell) clean-up procedure was also optimized, which speeds up the whole sample treatment. Arsenic species (As(III), MMA, DMA, As(V), AsB and AsC) were released from dried seafood tissues using pepsin as a protease, and the arsenic species were separated/quantified by anion exchange high performance liquid chromatography (HPLC) coupled to inductively coupled plasma-mass spectrometry (ICP-MS). Variables inherent to the enzymatic activity (pH, temperature and ionic strength), the amount of enzyme (pepsin), and factors affecting pressurization (pressure, static time, number of cycles and amount of dispersing agent, C-18) were fully evaluated. Pressurized assisted enzymatic hydrolysis (PAEH) with pepsin can be finished after few minutes (two cycles of 2min each one plus 3min to reach the hydrolysis temperature of 50°C). A total sample solubilisation is not achieved after the procedure, however it is efficient enough for breaking down certain bonds of bio-molecules and for releasing arsenic species. The developed method has been found to be precise (RSDs lower than 6% for As(III), DMA and As(V); and 3% for AsB) and sensitive (LOQs of 18.1, 36.2, 35.7, 28.6, 20.6 and 22.5ng/g for As(III), MMA, DMA, As(V), AsB and AsC, respectively). The optimized methodology was successfully applied to different certified reference materials (DORM-2 and BCR 627) which offer certified AsB and DMA contents, and also to different seafood products (mollusks, white fishes and cold water fishes). [ABSTRACT FROM AUTHOR] more...

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. Quantitative recoveries for inorganic and organic arsenic species have been obtained when using diatomaceous earth or octadecyl-functionalized silica gel (C18) as a solid support material, with a solid support mass/sample mass ratio of 7.0. Elution of arsenical compounds has been assessed using 10 mL of 50/50 methanol/ultrapure water as an elution solvent. The MSPD method has been found precise, with RSDs of ∼9% for As(III), DMA, and As(V) and 3% for AsB. The developed procedure has been tested by analyzing different certified reference materials of marine origin such as DORM-2 and BCR 627, which offer certified contents for some arsenic species. The method has been also applied to assess arsenic speciation in different mollusks, cold water fishes, and white fishes. [ABSTRACT FROM AUTHOR] more...