Health & Environmental Research Online (HERO)


PFHpA (375-85-9)


330 References Were Found:

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

FORMATION OF POLY(TETRAFLUOROETHYLENE) THIN-FILMS ON ALUMINA BY ADMICELLAR POLYMERIZATION

Authors: Lai, CL; Harwell, JH; Orear, EA (1995) HERO ID: 3859912

[Less] Partitioning of tetrafluoroethylene gas into admicelles of sodium perfluoroheptanoate on alumina was . . . [More] Partitioning of tetrafluoroethylene gas into admicelles of sodium perfluoroheptanoate on alumina was measured in a high-pressure reactor. Polymerization of tetrafluoroethylene within the adsorbed surfactant bilayer took place after thermal initiation with the formation of fluorocarbon thin films on aluminum oxide powder. In the formation of poly(tetrafluoroethylene) (PTFE), the effects of surfactant concentration and of initiator concentration were studied. Modified powder was characterized by a number of techniques including Fourier transform infrared (FTIR) spectroscopy, wavelength-dispersive spectroscopy (WDS), atomic force microscopy (AFM), and wettability testing. Measurements of friction coefficients and contact angles verified that a thin poly(tetrafluoroethylene) film was formed on alumina plates using the same procedure.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

REACTIONS OF BENZAMIDOXIME AND ITS SODIUM-SALT WITH METHYL-ESTERS OF FLUORINATED ACIDS

Authors: Ilin, VV; Kabakchi, EV; Ignatenko, AV (1993) HERO ID: 3859903

[Less] The reactions of benzamidoxime and its sodium salt with methyl esters of fluorinated acids at 20-100-degrees-C . . . [More] The reactions of benzamidoxime and its sodium salt with methyl esters of fluorinated acids at 20-100-degrees-C give 1,2,4-oxadiazoles or O-addition products.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

VOLATILE ION-PAIRING AGENTS FOR LIQUID-CHROMATOGRAPHIC THERMOSPRAY MASS-SPECTROMETRIC DETERMINATION OF AMINO-ACIDS AND AMINO-ACID AMIDES

Authors: Vanleuken, RGJ; Kwakkenbos, GTC; Duchateau, ALL (1993) Journal of Chromatography A 647:131-136. HERO ID: 3858440

[Less] The behaviour of volatile ion-pairing agents in terms of performance of the combined liquid chromatography-mass . . . [More] The behaviour of volatile ion-pairing agents in terms of performance of the combined liquid chromatography-mass spectrometry is described. The applicability of heptafluorobutanoic acid, tridecafluoroheptanoic acid and nonadecafluorodecanoic acid as volatile ion-pairing agents is demonstrated by the analysis of mixtures of amino acids and the corresponding amino acid amides. Translation of a non-volatile to a volatile ion-pair system that is suitable for thermospray mass spectrometry is described. Using nonadecafluorodecanoic acid, the retention times of the compounds studied were comparable to those obtained with n-dodecylsulphonic acid. Further, with nonadecafluorodecanoic acid, the repeatability of the tests and the calibration graphs of the compounds investigated were good. The sensitivity of the mass spectrometer towards the compounds of interest was greatly improved by postcolumn addition of trifluoroacetic acid and ionization with gaseous ammonia. Using nonadecafluorodecanoic acid, the method was applied to the analysis of samples from bio-organic synthesis.

Technical Report
Technical Report

Letter from 3M to USEPA regarding mechanistic two-year study of hepatic tumor induction in rats fed ammonium perfluoroalkyl carboxylates dated 10/11/93

Author: 3M (1993) HERO ID: 3797537

[Less] The test substance included ammonium perfluoroalkyl carboxylates (CAS No. 68259-11-0) which contains . . . [More] 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).

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

SOLUBILIZATION OF PADA IN HYDROCARBON FLUOROCARBON SURFACTANT MIXTURES

Authors: Connolly, TJ; Reinsborough, VC; Xiang, XY (1992) Australian Journal of Chemistry 45:769-775. HERO ID: 3859896

[Less] Solubilities of pyridine-2-azo-p-dimethylaniline (pada) were determined at 25-degrees-C in four mixed . . . [More] Solubilities of pyridine-2-azo-p-dimethylaniline (pada) were determined at 25-degrees-C in four mixed fluorocarbon/hydrocarbon short-chained surfactant systems: (i) sodium decyl sulfate/sodium perfluoroheptanoate; (ii) sodium octanesulfonate/sodium perfluorooctanoate; (iii) sodium octanesulfonate/sodium perfluoroheptanoate; (iv) sodium nonanesulfonate/sodium perfluoroheptanoate. Systems (i), (iii) and (iv) showed micellar miscibility (one mixed micelle) and synergistic solubilization effects. System (ii) had two critical micelle concentrations pointing to two micellar forms in solution, and no synergism could be detected. From these four examples, it is deduced that single mixed micelles are formed when the critical micelle concentrations of the pure surfactants are within a factor of 3 of each other.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

MICELLAR RATE ENHANCEMENT STUDIES IN MIXED SODIUM FLUOROCARBON HYDROCARBON SURFACTANT SOLUTIONS

Authors: Connolly, TJ; Reinsborough, VC (1992) HERO ID: 3859895

[Less] Stopped-flow kinetic studies were conducted in mixed micellar solutions of fluorocarbon and hydrocarbon . . . [More] Stopped-flow kinetic studies were conducted in mixed micellar solutions of fluorocarbon and hydrocarbon anionic surfactants to determine the prevalent micellar form. The probe reaction was the Ni(aq)2+/pyridine-2-azo-p-dimethylaniline (PADA) complexation, which is many times accelerated in the presence of anionic micelles. Binding constants for Ni(aq)2+ and PADA partitioning between bulk solution and micelles were determined through the murexide technique and solubility measurements respectively and the molar reaction volume was obtained from the Robinson equation. The three binary surfactant systems investigated had sodium perfluoroheptanoate as the fluorocarbon surfactant while the hydrocarbon surfactants were sodium decylsulfate, sodium nonanesulfonate, and sodium octanesulfonate. The kinetic results were consistent with unimicellar composition in all three systems which was not the behaviour previously found with the sodium octane sulfonate / sodium perfluoroctanoate system. The difference was attributed to closer similarity in the surfactant pair hydrophobicities as revealed through their critical micelle concentrations. Another finding was that mixed micelles synergistically can lead to a much greater solubilization of PADA than is possible through either of the pure surfactants.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

NMR-STUDY OF CYCLODEXTRIN INCLUSION OF FLUOROCARBON SURFACTANTS IN SOLUTION

Authors: Guo, W; Fung, BM; Christian, SD (1992) Langmuir 8:446-451. HERO ID: 3858555

[Less] The association of alpha-, beta-, and gamma-cyclodextrins with sodium perfluorobutanoate, sodium perfluoroheptanoate, . . . [More] The association of alpha-, beta-, and gamma-cyclodextrins with sodium perfluorobutanoate, sodium perfluoroheptanoate, sodium perfluorooctanoate, and sodium perfluorononanoate has been studied by F-19 NMR. First, the results suggest that the association of alpha-cyclodextrin with various fluorocarbon surfactants is fairly weak. The cavity of the host cyclodextrin is too small to accommodate the fluorocarbon chain to form an inclusion complex, but there exists an appreciable association between the tail of the surfactant and alpha-cyclodextrin. Secondly, the cavity of beta-cyclodextrin is large enough to accommodate the fluorocarbon chain, but the latter is forced to adopt an extended, possibly all-trans conformation to fit into the cavity. For perfluorosurfactants having a short fluorocarbon chain, a 1:1 complex is formed. When the fluorocarbon chain is longer, 2:1 complexation becomes significant for higher concentrations of beta-cyclodextrin. Thirdly, gamma-cyclodextrin forms a 1:1 complex with fluorocarbon surfactants. The complexation is stronger than that in the alpha-cyclodextrin/surfactant system but weaker than that in the beta-cyclodextrin/surfactant system. The association constants for the 1:1 complexes have been calculated from the dependence of the F-19 NMR chemical shift on the concentration of cyclodextrin.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

DETERMINATION OF VOLATILE AND NONVOLATILE ORGANIC-ACIDS IN TECHNICAL SUGAR SOLUTIONS BY ION-EXCLUSION CHROMATOGRAPHY

Authors: Accorsi, CA; Blo, G (1991) HERO ID: 3859870

[Less] Volatile and non-volatile organic acids present in sugar process juices were separated by ion-exclusion . . . [More] Volatile and non-volatile organic acids present in sugar process juices were separated by ion-exclusion chromatography on an HPICE-AS1 cation-exchange column (H+ form) using both dilute hydrochloric acid and 2-propanol-water solutions of tridecafluoroheptanoic acid. Coupled with an anion-exchange micromembrane suppressor, a conductivity detector made it possible to reveal citric, tartaric, gluconic, malic, lactic, succinic, glycolic, formic, acetic and pyrrolidonecarboxylic acid in the presence of inorganic acids and non-ionic organic matter. In sugar process juices subjected to alkaline and/or oxidative treatment, increasing concentrations of the major acid components, i.e., acetic, formic and lactic acid, can be measured. The analysis is performed in the presence of sucrose and a simple clean-up by rapid batch treatment with a cation exchanger (H+ form) is sufficient to remove proteins and cations. The multiple standard addition procedure is used for calibration.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

DETERMINATION OF LOW-MOLECULAR-WEIGHT ORGANIC-ACIDS COLLECTED ON SILICA-GEL AIR SAMPLING TUBES BY USING ION-EXCLUSION CHROMATOGRAPHY

Authors: Hekmat, M; Smith, RG (1991) HERO ID: 3859881

[Less] Ion-exclusion chromatographic separation of organic acids by using tridecafluoroheptanoic acid solution . . . [More] Ion-exclusion chromatographic separation of organic acids by using tridecafluoroheptanoic acid solution as the eluent and conductivity detection were studied. Air samples were collected on silica gel tubes and desorbed in water. The proposed method was applicable to the separation of formic, acetic, propionic, and butyric acids. The recovery of these four acids was above 95% when air was passed through the spiked tubes at a flow rate of 0.2 L/min for 3 hr. The method was validated for all four compounds at one-half the threshold limit value (TLV), at the TLV, and two times the TLV. No changes in recovery were observed in samples stored for up to 7 days. Desorbed samples were stable for up to 20 days.

The "refereed" or "peer review" status of a journal comes from the Ulrichsweb Global Serials Directory (http://ulrichsweb.serialssolutions.com/), as supplied by the publisher. The term refers to the system of critical evaluation of manuscripts/articles by professional colleagues or peers. The content of refereed publications is sanctioned, vetted, or otherwise approved by a peer-review or editorial board. The peer-review and evaluation system is utilized to protect, maintain, and raise the quality of scholarly material published in serials. Publications subject to the referee process are assumed, then, to contain higher quality content than those that are not.
Peer Reviewed Journal Article

MICELLES AND AGGREGATES OF FLUORINATED SURFACTANTS

Authors: Guo, W; Brown, TA; Fung, BM (1991) HERO ID: 3859880

[Less] The formation of micelles and aggregates by three kinds of fluorinated surfactants has been studied . . . [More] The formation of micelles and aggregates by three kinds of fluorinated surfactants has been studied by F-19 NMR, light scattering, microscopy, centrifugation, conductance measurement, and pH titration. The surfactants studied are perfluoroheptanoic acid, its salts, and its ethoxylated amides. By the use of F-19 NMR, the mean lifetime of the surfactant molecules exchanging between the monomeric state and the aggregated state was found to be about 10(-6)s for the salts, 10(-4)s for the acid, and 10(-1)s for the amides. The reason for the increase in the mean lifetime for the acid and the amides is the formation of aggregates above the critical micelle concentration. The aggregates have an average diameter of about 100-200 nm, which is much larger than ordinary micelles. They can be distinguished under a phase-contrast microscope and can be separated from the surfactant dispersion by centrifugation. Conductance measurements of perfluoroheptanoic acid indicate strong counterion binding in the aggregates, the formation of which is favored by a reduction of the net charge in the hydrophilic head groups. It was found that large aggregates start to form when about 20% of the sodium ions in the salt are replaced by protons. Judging from the characteristics of the F-19 NMR spectra of the nonionic fluorinated surfactants (ethoxylated amides) and the optical isotropy of the droplets viewed under a polarizing microscope, it is suggested that the aggregates may exist in a cubic phase.