Health & Environmental Research Online (HERO)


PFHxA (307-24-4)


249 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

Self-organization of amphiphilic polymer in vesicle bilayers composed of surfactant mixtures

Authors: Kang, SY; Seong, BS; Han, YS; Jung, HT (2003) Biomacromolecules 4:360-365. HERO ID: 2850417

[Less] Cryogenic transmission electron microscopy (cryo-TEM) and small angle neutron scattering (SANS) are . . . [More] Cryogenic transmission electron microscopy (cryo-TEM) and small angle neutron scattering (SANS) are used to investigate the association of amphiphilic polymers consisting of a double-chain hydrophobic tail attached onto poly(ethylene glycol) (PEG) polymer chains into two different systems of equilibrium vesicles. For cetyltrimethylammonium bromide (CTAB)/sodium perfluorohexanoate (FC(5)) vesicle bilayers, the size distribution of the vesicles slightly becomes narrow in the presence of the polymers, suggesting that the wedge-shaped polymers increase the spontaneous curvature of the vesicles. In contrast, the confinement of polymer molecules inside the CTAB/sodium perfluorooctanoate (FC(7)) vesicles that are stabilized by spontaneous curvature causes an abrupt decrease in the bilayer rigidity. By an analysis of vesicle size distribution, it is found that the membrane elasticity of CTAB/FC(7) vesicles is varied considerably from 6k(B)T to 0.3k(B)T, implying the transition of stabilization mechanism from spontaneous curvature to thermal fluctuation in the presence of polymer. The polymer incorporation mechanism into the bilayers is understood, in the comparison of the vesicle radius and size distribution before and after adding polymer, as that the polymer is anchored into the vesicle bilayer owing to hydrophobic property after the adsorption on the surface of the bilayer.

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

Phase behavior and microstructure of aqueous mixtures of cetyltrimethylammonium bromide and sodium perfluorohexanoate

Authors: Iampietro, DJ; Kaler, EW (1999) HERO ID: 3859925

[Less] The phase behavior and microstructure of aqueous mixtures of cetyltrimethylammonium bromide (C(16)TAB) . . . [More] The phase behavior and microstructure of aqueous mixtures of cetyltrimethylammonium bromide (C(16)TAB) and sodium perfluorohexanoate (FC5) were investigated as a function of total surfactant concentration, mixing ratio, and temperature. The aggregation behavior of both the pure components and several mixtures was studied via surface tension experiments, and analysis of the results using the regular solution model yielded a beta value of -19.4, indicating highly nonideal mixing. The evolution of phase behavior from the FC5-water binary axis with the addition of C16TAB was of particular interest. Below the critical micelle concentration or cmc of FC5 (5.70 wt %), the addition of small amounts of C16TAB leads to the formation of large structures, including vesicles, between surfactant concentrations of 2 and 4 wt %. Above the cmc, FC5 forms small globular micelles in solution. The addition of C16TAB to the FC5 micelles leads to an increase in viscosity and eventually phase separation into two rodlike micellar solutions, one enriched in FC5 and the other enriched in C16TAB. The microscopic structure of the vesicles and micelles was probed using small-angle neutron scattering, and the experimental data was analyzed with two complimentary methods. The vesicles were found to be polydisperse with average sizes ranging from 500 to 800 Angstrom (determined from light scattering) and a bilayer thickness of about 29 Angstrom. Consistent with the viscosity results, neutron-scattering measurements showed that the rodlike micelles undergo one-dimension growth and become more flexible near the phase boundary. Results from an indirect transform of the scattered intensity indicate that near the center of the aggregate cross section there is a region consisting solely of the hydrocarbon surfactant.

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 Perfluorocarboxylates in Groundwater Impacted by Fire-Fighting Activity

Authors: Moody, CA; Field, JA (1999) Environmental Science and Technology 33:2800-2806. HERO ID: 3005573

[Less] BIOSIS COPYRIGHT: BIOL ABS. Perfluorinated surfactants are used in aqueous film forming foam (AFFF) . . . [More] BIOSIS COPYRIGHT: BIOL ABS. Perfluorinated surfactants are used in aqueous film forming foam (AFFF) formulations, which are used to extinguish hydrocarbon-fuel fires. Virtually nothing is known about the occurrence of perfluorinated surfactants in the environment, in particular, at fire-training areas and emergency response sites where AFFF entered groundwater without prior treatment. Strong anion exchange Empore disks were used to extract perfluorocarboxylates from groundwater collected from fire-training facilities locat . The detection of perfluorocarboxylates at field sites after 7-10 years of inactivity indicates their potential utility as markers for delineating groundwater impacted by fire-fighting activity.

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 perfluorinated carboxylic acids in biological samples by high-performance liquid chromatography

Authors: Ohya, T; Kudo, N; Suzuki, E; Kawashima, Y (1998) Journal of Chromatography B: Biomedical Sciences and Applications 720:1-7. HERO ID: 2906110

[Less] This paper describes a method for the quantitative determination of perfluorinated carboxylic acids . . . [More] This paper describes a method for the quantitative determination of perfluorinated carboxylic acids (PFCAs), perfluorohexanoic acid (C6-PFCA), perfluoroheptanoic acid (C7-PFCA), perfluorooctanoic acid (C8-PFCA), perfluorononanoic acid (C9-PFCA) and perfluorodecanoic acid (C10-PFCA), in biological samples. PFCA in liver homogenates was extracted as an ion pair with tetrabutylammonium (TBA) ion into organic solvent, then the PFCA was derivatized with 3-bromoacetyl-7-methoxycoumarin (BrAMC) and quantified by HPLC with fluorescence detection. This method is applicable for the studies on tissue accumulation and elimination of PFCAs in animals after the administration.

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

Monolayer Properties of Long-Chain Alkylammonium Perfluorohexanoates on the Concentrated Sodium Chloride Solution

Authors: Shibata,; Moroi,; Saito,; Matuura, (1996) Journal of Colloid and Interface Science 184:175-180. HERO ID: 3859797

[Less] Surface pressure (pi)- and surface potential (DeltaV)-area (A) isotherms were obtained for monolayers . . . [More] Surface pressure (pi)- and surface potential (DeltaV)-area (A) isotherms were obtained for monolayers of alkylammonium perfluorohexanoates of four different alkyl chains (m) on water and 4.4 M NaCl solutions as a function of molecular area of various temperatures by the Langmuir and the ionizing electrode methods. As for octadecylammonium perfluorohexanoate (C18F11), the pi-A curves of these long-hydro-short-fluoro chain salt showed three phase transition points. Judging from the surface potential and the apparent molar quantity together with our previous data on the transitions, the first was assigned to the transition from the expanded (E) phase to the condensed (C-I) phase, the second from the C-I phase to another condensed (C-I') phase, and the third from the (C-I') phase to another condensed (C-II) phase. From the surface potential, the apparent molar entropy change, and the phase diagram, the orientation of long-hydro-short-fluoro chain salts in the monolayer state was discussed.

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

Perfluorinated acid alternatives to trifluoroacetic acid for reversed-phase high-performance liquid chromatography

Authors: Pearson, JD; Mccroskey, MC (1996) Journal of Chromatography A 746:277-281. HERO ID: 3858375

[Less] Over the past decade trifluoroacetic acid (TFA) has become the ion-pairing agent (IPA) of choice for . . . [More] Over the past decade trifluoroacetic acid (TFA) has become the ion-pairing agent (IPA) of choice for reversed-phase high-performance liquid chromatography (RP-HPLC) of peptides and proteins. Reagent grade TFA is highly pure, water soluble, transparent at 220 nm and readily volatile. A drawback of this universal appeal is that several alternative perfluorinated carboxylic acids tend to be overlooked when TFA does not work in a particular separation. Examples are given comparing TFA selectivity with those of pentafluoropropionic acid, heptafluorobutyric acid, perfluoropentanoic acid, perfluorohexanoic acid and perfluoroheptanoic acid. We have found that increasing the IPA n-alkyl chain length can resolve sample components that otherwise co-elute in the void volume of TFA-based RP-HPLC. Examples are given for the resolution of an oligoglycine series and enhanced selectivity for a bovine hypothalamic extract.

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).

Technical Report
Technical Report

Acute oral toxicity screen with T-2712CoC in albino rats. Experiment no. 0479AR0680

Author: Riker Labs (1979) (8EHQ-04-15674A; 88040000247). St. Paul, MN: 3M Company. [TSCA Submission] HERO ID: 3921144


Technical Report
Technical Report

Read-across for 90-day rat oral repeated-dose toxicity for selected perfluoroalkyl acids: A case study

Authors: Schultz, T.W.; Mellor, C.; Przybylak, K.; Escher, S; Judson, R.; Tsakovka, I.; and Richarz, A. European Chemicals Agency. HERO ID: 3878944