Abstract  In epidemiological research, it has become increasingly important to assess subjects' exposure to different classes of chemicals in multiple environmental media. It is a common practice to aliquot limited volumes of samples into smaller quantities for specific trace level chemical analyses. A novel method was developed for the determination of 14 perfluorinated alkyl acids (PFAAs) in small volumes (10mL) of drinking water using off-line solid phase extraction (SPE) pre-treatment followed by on-line pre-concentration on a WAX column before analysis on column-switching high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). In general, large volumes (100-1000mL) have been used for the analysis of PFAAs in drinking water. The current method requires approximately 10mL of drinking water concentrated by using an SPE cartridge and eluted with methanol. A large volume injection of the extract was introduced on to a column-switching HPLC-MS/MS using a mix-mode SPE column for the trace level analysis of PFAAs in water. The recoveries for most of the analytes in the fortified laboratory blanks ranged from 73±14% to 128±5%. The lowest concentration minimum reporting levels (LCMRL) for the 14 PFAAs ranged from 0.59 to 3.4ng/L. The optimized method was applied to a pilot-scale analysis of a subset of drinking water samples from an epidemiological study. These samples were collected directly from the taps in the households of Ohio and Northern Kentucky, United States and the sources of drinking water samples are both surface water and ground water, and supplied by different water distribution facilities. Only five PFAAs, perfluoro-1-butanesulfonic acid (PFBS), perfluoro-1- -hexanesulfonic acid (PFHxS), perfluoro-1-octanesulfonic acid (PFOS), perfluoro-n-heptanoic acid (PFHpA) and perfluoro-n-octanoic acid (PFOA) are detected above the LCMRL values. The median concentrations of these five PFAAs detected in the samples was ≤4.1ng/L with PFOS at 7.6ng/L and PFOA at 10ng/L. Concentrations of perfluoro-1-decanesulfonic acid, PFDS and other perfluoroalkyl carboxylic acids were below the LCMRL values.

Abstract  Human exposure to perfluoroalkyl substances (PFASs) occurs primarily via dietary intake and drinking water. In this study, 16 PFASs have been assessed in 96 drinking waters (38 bottled waters and 58 samples of tap water) from Brazil, France and Spain. The total daily intake and the risk index (RI) of 16 PFASs through drinking water in Brazil, France and Spain have been estimated. This study was carried out using an analytical method based on an online sample enrichment followed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The quality parameters of the analytical method were satisfactory for the analysis of the 16 selected compounds in drinking waters. Notably, the method limits of detection (MLOD) and method limits of quantification (MLOQ) were in the range of 0.15 to 8.76ng/l and 0.47 to 26.54ng/l, respectively. The results showed that the highest PFASs concentrations were found in tap water samples and the more frequently found compound was perfluorooctanesulfonic acid (PFOS), with mean concentrations of 7.73, 15.33 and 15.83ng/l in French, Spanish and Brazilian samples, respectively. In addition, PFOS was detected in all tap water samples from Brazil. The highest level of PFASs contamination in a single sample was 140.48ng/l in a sample of Spanish tap water. In turn, in bottled waters the highest levels were detected in a French sample with 116ng/l as the sum of PFASs. Furthermore, the most frequent compounds and those at higher concentrations were perfluoroheptanoic acid (PFHpA) with a mean of frequencies in the three countries of 51.3%, followed by perfluorobutanesulfonic acid (PFBS) (27.2%) and perfluorooctanoic acid (PFOA) (23.0%). Considering that bottled water is approximately 38% of the total intake, the total PFASs exposure through drinking water intake for an adult man was estimated to be 54.8, 58.0 and 75.6ng/person per day in Spain, France and Brazil, respectively. However, assuming that the water content in other beverages has at least the same levels of contamination as in bottled drinking water, these amounts were increased to 72.2, 91.4 and 121.0ng/person per day for an adult man in Spain, France and Brazil, respectively. The results of total daily intake in different gender/age groups showed that children are the most exposed population group through hydration with maximum values in Brazil of 2.35 and 2.01ng/kg body weight (BW)/day for male and female, respectively. Finally, the RI was calculated. In spite of the highest values being found in Brazil, it was demonstrated that, in none of the investigated countries, drinking water pose imminent risk associated with PFASs contamination.

Abstract  This study provides the first evidence on the influence of the semiconductor and electronics industries on perfluorinated chemicals (PFCs) contamination in receiving rivers. We have quantified ten PFCs, including perfluoroalkyl sulfonates (PFASs: PFBS, PFHxS, PFOS) and perfluoroalkyl carboxylates (PFCAs: PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnA, PFDoA) in semiconductor, electronic, and optoelectronic industrial wastewaters and their receiving water bodies (Taiwan's Keya, Touchien, and Xiaoli rivers). PFOS was found to be the major constituent in semiconductor wastewaters (up to 0.13 mg/L). However, different PFC distributions were found in electronics plant wastewaters; PFOA was the most significant PFC, contributing on average 72% to the effluent water samples, followed by PFOS (16%) and PFDA (9%). The distribution of PFCs in the receiving rivers was greatly impacted by industrial sources. PFOS, PFOA and PFDA were predominant and prevalent in all the river samples, with PFOS detected at the highest concentrations (up to 5.4 microg/L).

Abstract  We developed a procedure for the direct determination of dissolved free amino acids (DFAAs) in freshwater samples employing ion-pairing liquid chromatography and mass spectrometry. Our approach allowed accurate quantification of subnanomolar concentrations of DFAAs without prior concentration, derivatization or sample clean-up steps, achieving a throughput of three samples per hour. DFAAs were separated on a C-18 resin using tridecafluoroheptanoic acid as an ion-pairing agent controlling the overall retention. The relative standard deviation of DFAA measurements was <10% in samples from the mesotrophic Lake Zurich (Switzerland), and across concentrations of 0.5-500 nM. Recoveries of DFAAs ranged from 94 to 102% within the range of 0.2-10 nM. The limits of quantification for individual DFAAs varied between 50 pM to 2 nM (median, 0.5 nM). The new method was employed to compare the spatial variability of DFAA concentrations in samples obtained by two devices. Epilimnetic samples of different size (ml, 1) were collected at various spatial scales (cm, m, km) with a traditional 51 Friedinger sampler and with a custom-made multi-syringe sampling apparatus. Concentrations of total DFAAs ranged from 30 to 330 nM. Alanine, serine, glutamic acid, arginine and glycine constituted 65% of the total pool, while methionine and tryptophan occurred at sub-nM concentrations only. Concentrations of individual DFAAs varied spatially over 2 orders of magnitude. Their spatial distribution was positively skewed, as characterized by rare peaks, most strongly so for glutamate, glycine and asparagine. The composition of DFAAs significantly differed at all examined spatial scales, and this could be mainly attributed to alanine, aspartic acid, and glycine. Our new method equals or outperforms existing ones in terms of sensitivity and reproducibility, while its procedural simplicity renders it superior for the high-throughput analysis of freshwater samples. (C) 2016 Elsevier B.V. All rights reserved.

Abstract  Per- and polyfluoroalkyl substances (PFASs) are a class of compounds with unique chemical properties that have been shown useful in a wide variety of applications because they provide materials with reduced surface tension and exceptional non-stick properties. PFASs are commonly found in impregnation materials, coatings of papers and textiles, fire-fighting foams, pesticides, and cleaning agents. The potential for human exposure to PFASs is high because of their widespread distribution. The aim of this study was to investigate levels of PFASs in men and women from Sweden and to assess the influence of gender and parity among women. Levels of 13 PFASs were determined in plasma samples collected during 2001-2004 from 1016 (507 women) 70year-old participants from the population-based Prospective Study of the Vasculature in Uppsala Seniors (PIVUS). The PFASs studied were nine perfluorinated carboxylic acids (PFCAs), four perfluorinated sulfonic acids (PFSAs) and perfluorooctane sulfonamide (PFOSA). In addition, structural isomers of perfluorooctane sulfonic acid (PFOS) were determined in a subset of 398 individuals. The detection rates were high and the majority of the studied compounds were detected in more than 75% of the participants. Levels of the selected analytes were found to be similar to other studies of non-occupationally exposed populations. Gender differences were observed in levels of PFHpA which was higher in men, while PFHxS was higher in women. Parity among women was shown to have a minor effect on PFAS concentrations and we found primi- and multiparous women to have slightly lower levels of PFUnDA when compared to nulliparous women.

Abstract  Concern over persistence, bioaccumulation, and toxicity has led to international regulation and phase-outs of certain perfluorinated compounds and little is known about their replacement products. High resolution mass spectrometry was used to investigate the occurrence and identity of replacement fluorinated compounds in surface water and sediment of the Tennessee River near Decatur, Alabama. Analysis of legacy Per- and polyfluoroalkyl substances (PFASs) revealed a marked increase in concentrations downstream of manufacturing facilities, with the most abundant compounds being perfluorooctanesulfonate (PFOS), perfluorobutanesulfonate (PFBS), and perfluorooctanoic acid (PFOA) as high as 220 ng L(-1), 160 ng L(-1), and 120 ng L(-1), respectively. A series of nine polyfluorinated carboxylic acids was discovered, each differing by CF2CH2. These acids are likely products or byproducts of a manufacturing process that uses 1,1-difluoroethene, which is registered to a manufacturing facility in the area. Two other predominant compounds discovered have structures consistent with perfluorobutanesulfonate and perfluoroheptanoic acid but have a single hydrogen substituted for a fluorine someplace in their structure. A polyfluoroalkyl sulfate with differing mixes of hydrogen and fluorine substitution was also observed. N-methyl perfluorobutane sulfonamidoacetic acid (MeFBSAA) was observed at high concentrations and several other perfluorobutane sulfonamido substances were present as well.

Abstract  Per- and polyfluoroalkyl substances (PFASs), including fluorotelomer alcohols (FTOHs), perfluoroalkyl sulfonamidoethanols (FOSEs), and perfluoroalkyl sulfonamides (FOSAs), were assessed in 61 residential indoor air and 15 personal air samples collected in Oslo area, Norway. FTOHs were detected in all samples, and the median concentrations in residential indoor air were 2970, 10400, and 3120 pg m-3 for 6:2, 8:2, and 10:2 FTOH, respectively. This is similar to or higher than previously reported in studies from the same geographical area and worldwide. FOSEs and FOSAs were detected in 49-70% and 7-13% of the residential indoor air samples, respectively. The median FTOH concentrations observed in personal air were 1970, 7170, and 1590 pg m-3 for 6:2, 8:2, and 10:2 FTOH, respectively, which is 30 to 50% lower than the median concentrations in residential indoor air. No FOSEs or FOSAs were detected above the method detection limit (MDL) in the personal air samples. Intakes of perfluorohexanoate (PFHxA), perfluoroheptanoate (PFHpA), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorodecanoate (PFDA), perfluoroundecanoate (PFUnDA), and perfluorooctyl sulfonate (PFOS) through inhalation and biotransformation of PFAS precursors in air were estimated. Median intakes of 1.7, 0.17, 5.7, 0.57, 1.8, 0.18, and 2.3 pg kg bw-1 day-1 were obtained in residential indoor air, while 1.0, 0.10, 3.3, 0.33, 0.88, and 0.09 pg kg bw-1 day-1 were found in personal air for PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnDA, and PFOS, respectively. The median PFOA intakes from residential indoor air (5.7 pg kg bw-1 day-1) and personal air (3.3 pg kg bw-1 day-1) were both around 5 orders of magnitude lower than the tolerable daily intake (TDI) reported by the European Food Safety Authority (EFSA).

Abstract  In the present study, a highly selective fluorous affinity-based dispersive liquid-liquid microextraction (DLLME) technique was developed for the extraction and analysis of per- and polyfluoroalkyl substances (PFASs) followed by high performance liquid chromatography tandem-mass spectrometry. Perfluoro-tert-butanol with multiple C-F bonds was chosen as the extraction solvent, which was injected into the aqueous samples with a dispersive solvent (acetonitrile) in a 120:800 (μL, v/v) mixture for PFASs enrichment. The fluorous affinity-based extraction mechanism was confirmed by the significantly higher extraction recoveries for PFASs containing multiple fluorine atoms than those for compounds with fewer or no fluorine atoms. The extraction recoveries of medium and long-chain PFASs (CF2 > 5) exceeded 70%, except perfluoroheptanoic acid, while those of short-chain PFASs were lower than 50%, implying that the proposed DLLME may not be suitable for their extraction due to weak fluorous affinity. This highly fluoroselective DLLME technique can greatly decrease the matrix effect that occurs in mass spectrometry detection when applied to the analysis of urine samples. Under the optimum conditions, the relative recoveries of PFASs with CF2 > 5 ranged from 80.6-121.4% for tap water, river water and urine samples spiked with concentrations of 10, 50 and 100 ng/L. The method limits of quantification for PFASs in water and urine samples were in the range of 0.6-8.7 ng/L. Furthermore, comparable concentrations of PFASs were obtained via DLLME and solid-phase extraction, confirming that the developed DLLME technique is a promising method for the extraction of PFASs in real samples.

Abstract  Modification of chemical fibres with copolymers of 1,1-dihydroperfluoro-heptyl acrylate (PFHA) to decrease their wettability was systematically investigated and some characteristics of this process were established. It was shown that the effectiveness of modification is determined by the method of treating the fibres with the copolymer modifiers, the molecular composition of these copolymers, and the colloid chemical properties of the latexes based on them. Treatment of the fibres with copolymers with functionally active groups capable of reacting with the macromolecule of the fibre-forming polymer and cross-linking on the surface of the fibre is the most effective method of modification. Substitution of incomplete fluorinated alcohols or unfluorinated monomers for the acrylates in the PFHA copolymer reduces their effectiveness in modification. Copolymers of PFHA with hydrophilic monomers capable of being orientedly sorbed by the fibre due to its amphiphilic nature and forming surfaces with low energy are an exception. For effective use of the copolymer modifier, the latexes of these copolymers should have certain colloid chemical properties: the particle charge, adsorption saturation, and aggregate stability should be optimum, which will ensure their stability during preparation, storage, and use.

Abstract  The test substance included ammonium perfluoroalkyl carboxylates (CAS No. 68259-11-0) which contains 93 to 97% ammonium perfluorooctanoate (CAS No. 3825-26-1), and smaller amounts of ammonium perfluoroheptanoate (CAS No. 6130-43-4) and ammonium perfluorohexanoate (CAS No. 21615-47-4). The test substance was investigated in a mechanistic bioassay investigating extra hepatic tumor induction by compounds which induce peroxisome proliferation. In this mechanistic bioassay, 300 ppm of the test substance was fed to rats as part of their diet for 2-years. In addition to an ad libitum control, a second control group was pair-fed to the 300 ppm test group to control for the effects of reduced body weight. Increased incidences of combined (single, multiple) hepatic adenomas, Leydig cell adenomas, and pancreatic acinar cell adenomas were seen in the 300 ppm test group when compared to either the ad libitum or pair-fed controls. The tumor incidences (liver, testis, pancreas) were outside the historical control incidence range for DuPont Haskell Laboratory. In addition, age- adjustment statistics also support the conclusion that the tumor incidence was elevated for the liver (both controls), pancreas (pair-fed control), and testis (pair-fed control).

Abstract  Polyfluorinated compounds (PFCs) are authorized for use as greaseproofing agents in food contact paper. As C8-PFCs (8-carbons) are known to accumulate in tissues, shorter-chain C6-PFCs (6-carbons) have replaced C8-PFCs in many food contact applications. However, the potential of C6-PFCs for human biopersistence has not been fully evaluated. For the first time, we provide internal exposure estimates to key metabolites of 6:2 fluorotelomer alcohol (6:2 FTOH), a monomeric component of C6-PFCs, to extend our understanding of exposure beyond estimates of external exposure. Pharmacokinetic data from published rat and human studies on 6:2 FTOH were used to estimate clearance and area under the curve (AUC) for its metabolites: 5:3 fluorotelomer carboxylic acid (5:3 A), perfluorohexanoic acid (PFHxA) and perfluoroheptanoic acid (PFHpA). Internal exposure to 5:3 A was the highest of evaluated metabolites across species and it had the slowest clearance. Additionally, 5:3 A clearance decreased with increasing 6:2 FTOH exposure. Our analysis provides insight into association of increased internal 5:3 A exposure with high biopersistence potential of 6:2 FTOH. Our results identify 5:3 A as an important biomarker of internal 6:2 FTOH exposure for use in biomonitoring studies, and are potentially useful for toxicological assessment of chronic dietary 6:2 FTOH exposure.

Abstract  Biotransformation of fluorotelomer alcohols (FTOHs) is widely considered as an additional source of perfluorocarboxylic acids (PFCAs) in environmental biota. Compared with the extensive studies conducted in animals and microbes, biotransformation pathways of FTOHs in plants are still unclear. In this study, a hydroponic experiment was conducted to investigate the uptake, translocation and metabolism of 8:2 FTOH in soybean (Glycine max L. Merrill) over 144 h. 8:2 FTOH and its metabolites were found in all parts of soybean plants. At the end of the exposure, 7:3 FTCA [F(CF2)7CH2CH2COOH] was the primary metabolite in roots and stems, while PFOA [F(CF2)7COOH] was predominant in leaves. PFOA and 7:3 FTCA in the soybean-solution system accounted for 6.01 and 5.57 mol % of the initially applied 8:2 FTOH, respectively. Low levels of PFHpA [F(CF2)6COOH] and PFHxA [F(CF2)5COOH] in solutions and soybean roots resulted from microbial metabolism and plant root uptake. Glutathione-conjugated metabolites in soybean tissues were also identified. The activities of alcohol dehydrogenase, aldehyde dehydrogenase, and glutathione S-transferase in soybean roots increased during the exposure, suggesting their roles in 8:2 FTOH metabolism in soybean. This study provides important information for a better understanding of the uptake and metabolism of FTOHs and fluorotelomer-based compounds in plants.

Abstract  The spatial and temporal distribution of per- and polyfluoroalkyl substances (PFASs) in the open Western Mediterranean Sea waters was investigated in this study for the first time. In addition to surface water samples, a deep water sample (1390 m depth) collected in the center of the western basin was analyzed. Perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorohexanesulfonate (PFHxS) and perfluorooctanesulfonate (PFOS) were detected in all samples and were the dominant PFASs found. The sum of PFAS concentrations (ΣPFASs) ranged 246-515 pg/L for surface water samples. PFASs in surface water had a relatively homogeneous distribution with levels similar to those previously measured in the Atlantic near the Strait of Gibraltar, in water masses feeding the inflow to the Mediterranean Sea. Higher concentrations of PFHxA, PFHpA and PFHxS were, however, found in the present study. Inflowing Atlantic water and river/coastal discharges are likely the major sources of PFASs to the Western Mediterranean basin. Slightly lower (factor of 2) ΣPFASs was found in the deep water sample (141 pg/L). Such a relatively high contamination of deep water is likely to be linked to recurring deep water renewal fed by downwelling events in the Gulf of Lion and/or Ligurian Sea.

Abstract  Perfluoroheptanoic acid was employed as a volatile micellar phase in background electrolyte for micellar electrokinetic chromatography-tandem mass spectrometry separation and determination of 15 selected naphthoyl- and phenylacetylindole- synthetic cannabinoids and main metabolites derived from JWH-018, JWH-019, JWH-073, JWH-200 and JWH-250. The influence of concentration of perfluoroheptanoic acid in background electrolytes on the separation was studied as well as the influence of perfluoroheptanoic acid on mass spectrometry detection. The background electrolyte consisted of 75 mM perfluoroheptanoic acid, 150 mM ammonium hydroxide pH 9.2 with 10% (v/v) propane-2-ol allowed micellar electrokinetic chromatography separation together with mass spectrometry identification of the studied parent synthetic cannabinoids and their metabolites. The limits of detection of studied synthetic cannabinoids and metabolites were in the range from 0.9 ng/mL for JWH-073 to 3.0 ng/mL for JWH-200 employing liquid-liquid extraction. The developed method was applied on the separation and identification of studied analytes after liquid-liquid extraction of spiked urine and serum samples to demonstrate the potential of the method applicability for forensic and toxicological purposes.

Abstract  The title compound, cis-di-μ-perfluoroheptanoato-κ(4)O:O'-bis[dicarbonyl(dimethyl sulfoxide-κS)ruthenium(I)](Ru-Ru), [Ru2(C7F13O2)2(C2H6OS)2(CO)4], is a sawhorse-type dinuclear ruthenium complex with two bridging perfluoroheptanoate ligands, and with two dimethyl sulfoxide (DMSO) ligands in the axial positions coordinating via the S atoms. It is a new example of a compound with an aliphatic fluorinated carboxylate ligand. The Ru-Ru bond distance of 2.6908 (3) Å indicates a direct Ru-Ru interaction. The compound is an active catalyst in transvinylation of propionic acid with vinyl acetate.

Abstract  Methylmalonic aciduria (MMA) is one of the most frequent organic acidurias, a class of diseases caused by enzymatic defects mainly involved in the catabolism of branched-chain amino acids. Recently, mild MMA and C4-dicarboxylyl-carnitine (C4DC-C) accumulation have been reported in patients carrying mutation in genes encoding the α-subunit (SUCLG1) and the β-subunit (SUCLA2) of the ADP-forming succinyl-CoA synthetase (SCS). We developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantify in dried blood spot the two isobaric compounds of C4DC-C, succinyl-carnitine and methylmalonyl-carnitine, to allow the differential diagnosis between classical MMA and SCS-related defects. This method, with an easy liquid-phase extraction and derivatization procedure, has been validated to demonstrate the specificity, linearity, recovery, lowest limit of quantification (LLOQ), accuracy and precision for quantitative determination of blood succinyl-carnitine and methylmalonyl-carnitine. The assay was linear over a concentration range of 0.025-10 μmol/L and achieved the LLOQ of 0.025 μmol/L for both metabolites. The average slope, intercept, and coefficient of linear regression (r(2)) were respectively: 0.3389 (95% confidence interval 0.2888-0.3889), 0.0113 (95% confidence interval -0.0157 to 0.0384), 0.9995 (95% confidence interval 0.9990-1.0000) for succinyl-carnitine and 0.5699 (95% confidence interval 0.5263-0.6134), 0.0319 (95% confidence interval -0.0038 to 0.0677), 0.9997 (95% confidence interval 0.9995-1.0000) for methylmalonyl-carnitine. Within-day and between-day coefficients of variation (CV) were 1.94% and 3.19% for succinyl-carnitine and 3.21%, and 2.56 for methylmalonyl-carnitine. This method is accurate and provides a new tool to differentiate patients with classical methylmalonic acidemia from those with SCS-related defects.

Abstract  Amino acids extracted from a biological matrix can be resolved and measured using a 6-min per sample method through high-performance liquid chromatography with a short C18 column and rapid gradient using the ion-pairing reagent perfluoroheptanoic acid. LC-tandem mass spectrometry with multiple reaction monitoring (MRM) transitions selective for each compound allows simultaneous quantification of the 20 proteinogenic amino acids and 5 metabolically related compounds. Distinct MRM transitions were also established for selective detection of the isomers leucine/isoleucine and threonine/homoserine.

Abstract  This paper describes a fast method for the sensitive and selective determination of melamine in a wide range of food matrices, including several milk-based products. The method involves an extraction with aqueous 1% trichloroacetic acid before the injection of the 10-fold diluted extract into the liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS) system, using labelled melamine as the internal standard. As melamine is present in aqueous media in the cationic form, the chromatographic separation in reversed-phase LC requires the use of anionic ion-pair reagents, such as tridecafluoroheptanoic acid (THFA). This allows a satisfactory chromatographic retention and peak shape in all the types of food samples investigated. The method has been validated in six food matrices (biscuit, dry pasta and four milk-based products) by means of recovery experiments in samples spiked at 1 and 5 mg kg(-1). Average recoveries (n=5) ranged from 77% to 100%, with excellent precision (RSDs lower than 5%) and limits of detection between 0.01 and 0.1 mg kg(-1). In addition, accuracy and robustness of the method was proven in different soya-based matrices by means of quality control (QC) sample analysis. QC recoveries, at 1 and 2.5 mg kg(-1), were satisfactory, ranging from 79% to 110%. The method developed in this work has been applied to the determination of melamine in different types of food samples. All detections were confirmed by acquiring two MS/MS transitions (127>85 for quantification; 127>68 for confirmation) and comparing their ion intensity ratio with that of reference standards. Accuracy of the method was also assessed by applying it to a milk-based product and a baking mix material as part of an EU proficiency test, in which highly satisfactory results were obtained.

Abstract  This letter illustrates for the first time the preparation of p-methyl methacrylate/n-butyl acrylate/heptadecafluorodecyl methacrylate (p-MMA/nBA/FMA) colloidal dispersions containing up to 15% w/w FMA, which is accomplished by the utilization of biologically active phospholipids (PLs) and ionic surfactants. The use of monomer-starved conditions during emulsion polymerization and the utilization of 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC), sodium dodecyl sulfate (SDS), and phosphoric acid bis(tridecafluoro-octyl) ester ammonium salt (FSP) as surfactants, which function as transfer and dispersing agents, facilitate a suitable environment for the polymerization of p-MMA/nBA/FMA colloidal dispersions that exhibit nonspherical particle morphologies. Such nonspherical particles upon coalescence form phase-separated films with unique surface properties.

Abstract  Decomposition of perfluorinated chemicals is of significant interest in both scientific and industrial perspectives. Here, we report the decomposition of perfluorooctanoic acid (PFOA) under sonication-assisted photocatalysis by utilizing commercial TiO(2) (RdH) and home-made TiO(2) (sol-gel) as photocatalysts at ambient temperature, pressure and near neutral pH with the irradiation of 254nm UV light. PFOA was decomposed into fluoride ions and to several perfluorinated carboxylic acids (PFCAs) with a shorter carbon chain length such as perfluoroheptanoic acid (PFHpA), perfluorohexanoic acid (PFHxA), perfluoropropanoic acid (PFPA), and trifluoroacetic acid (TFA). The efficiency of sonication-assisted photocatalysis was found to be 64%. In all the cases, higher efficiencies were obtained when sol-gel TiO(2) was used as a photocatalyst than the commercial RdH TiO(2) catalyst. The specific surface area is three times higher for sol-gel TiO(2) than commercial RdH TiO(2) and appears to be the probable reason for the observed differences in the corresponding efficiencies. It is also interesting to note that pH plays a determining role in the decomposition of PFOA and correspondingly photocatalyses were carried out under different controlled pH. Perfluoroalkyl radicals are presumably oxidized by superoxide and hydroxyl radicals generated during the TiO(2)-mediated photocatalysis at pH 4 and 10, respectively. The role of sonication in sonication-assisted photocatalysis was construed to be an aid to photocatalysis than a tool itself. Sonication enhances photocatalysis through physical dispersion of TiO(2) and eases mass transfer which keeps on rejuvenating the TiO(2) surface.

Abstract  A major question regarding the global distribution of perfluorochemicals (PFCs) is one of transport. It has been suggested that atmospheric transport of volatile precursor compounds to remote areas and subsequent degradation to the nonvolatile PFCs is responsible for contamination of biota. This paper presents surface water PFC concentrations aimed at identifying tracers of atmospheric sources. Concentrations of PFCs including perfluorocarboxylates from C6 to C10 and perfluorooctane sulfonate (PFOS) are presented here from urban surface waters with presumably both atmospheric and nonatmospheric sources of PFCs, remote waters with only atmospheric sources of PFCs, and Lake Michigan. Perfluoroheptanoic acid (PFHpA) and perfluorooctanoic acid (PFOA) were detected in all surface water samples, and PFOS was detected in all but two samples. PFOS concentrations ranged from nondetect to 1.2 ng/L and from 2.4 to 47 ng/L in remote and urban surface waters, respectively. PFOA concentrations ranged from 0.14 to 0.66 ng/L and from 0.45 to 19 ng/L in remote and urban surface waters, respectively. The ratio of PFHpA to PFOA increased with increasing distance from nonatmospheric sources suggesting that it can be used as a tracer of atmospheric deposition of PFCs to surface waters. The ratio ranged from 0.5 to 0.9 in urban areas and from 6 to 16 in remote areas. Applying this tracer to measurements from Lake Michigan indicates that the primary source of PFCs to Lake Michigan is nonatmospheric, most likely inputs from wastewater treatment effluent.

Abstract  In this work we studied and compared the physicochemical properties of perfluorinated (sodium perfluoroheptanoate, C7FONa, and perfluorooctanoate, C8FONa) and hydrogenated (sodium octanoate, C8HONa, decanoate, C10HONa, and dodecanoate, C12HONa) amphiphiles. First, we determined their Krafft points to study the solubility and appropriate temperature range of micellization of these compounds. The critical micelle concentration (cmc) and ionization degree of micellization (beta) as a function of temperature (T) were estimated from conductivity data. Plots of cmc vs T appear to follow the typical U-shaped curve with a minimum T(min). The results show that the surfactants with CF2/CH2 ratio of 1.5 between alkyl chains (C12HONa-C8FONa and C10HONa-C7FONa) have nearly the same minimum value for cmc against temperature. The comparison between the cmc of hydrogenated amphiphiles and the corresponding perfluorinated amphiphiles must be done at this point. Thermodynamic functions of micellization were obtained by applying different theoretical models and choosing the one that best fit our experimental data. Although perfluorinated and hydrogenated amphiphiles present similar thermodynamic behavior, we have found a variation of 1.3 to 1.7 in the CF2/CH2 ratio, which did not remain constant with temperature. In the second part of this study the apparent molar volumes and adiabatic compressibilities were determined from density and ultrasound velocity measurements. Apparent molar volumes at infinite dilution presented the ratio 1.5 between alkyl chains again. However, apparent molar volumes upon micellization for sodium perfluoroheptanoate indicated a different aggregation pattern.

Abstract  Analysis of the (1)H NMR chemical shift variations for the methyl protons of sodium decanoate and decanoic acid in D(2)O solutions using reduced variables is consonant with a narrow distribution of sizes about the mean aggregation number for decanoate ion micelles, in contrast with decanoic acid polydisperse aggregates which increase their size with concentration, until phase separation is reached. At defined temperatures between 10 and 50 degrees C, the chemical shift coefficients for the methyl group protons exhibit a negative temperature slope (shielding) for decanoate ion micelles and a positive temperature slope (deshielding) for decanoic acid aggregates. These results suggest that an increase of temperature improves the mobility of the decanoate ion chains in the micelles, thus inducing the methyl groups of the decanoate ion micelles to spend more time near the micelle-water interfaces. In turn, the size of polydisperse decanoic acid aggregates increases with temperature.