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Per- and polyfluoroalkyl substances (PFAS), a highly persistent and potentially toxic class of chemicals, are added to cosmetics to increase their durability and water resistance. To assess this potential health and environmental risk, 231 cosmetic products purchased in the U.S. and Canada were screened for total fluorine using particle-induced gamma-ray emission spectroscopy. Of the eight categories tested, foundations, mascaras, and lip products had the highest proportion of products with high total fluorine ≥0.384 μg F/cm2. Twenty-nine products including 20 with high total fluorine concentrations were analyzed using targeted LC-MS/MS and GC-MS. PFAS concentrations ranged from 22–10,500 ng/g product weight, with an average and a median of 264 and 1050 ng/g product weights, respectively. Here, 6:2 and 8:2 fluorotelomer compounds, including alcohols, methacrylates, and phosphate esters, were most commonly detected. These compounds are precursors to PFCAs that are known to be harmful. The ingredient lists of most products tested did not disclose the presence of fluorinated compounds exposing a gap in U.S. and Canadian labeling laws. The manufacture, use, and disposal of cosmetics containing PFAS are all potential opportunities for health and ecosystem harm. Given their direct exposure routes into people, better regulation is needed to limit the widespread use of PFAS in cosmetics., Environmental Science & Technology Letters, 8 (7), ISSN:2328-8930

Per- and polyfluoroalkyl substances (PFAS) are a class of over 4700 fluorinated compounds used in industry and consumer products. Studies have highlighted the use of aqueous film-forming foams (AFFFs) as an exposure source for firefighters, but little is known about PFAS occurrence inside fire stations, where firefighters spend most of their shifts. In this study, we aimed to characterize PFAS concentrations and sources inside fire stations. We measured 24 PFAS (using LC–MS/MS) and total fluorine (using particle-induced gamma ray emission) in dust from multiple rooms of 15 Massachusetts stations, many of which (60%) no longer use PFAS-containing AFFF at all and the rest of which only use it very rarely. Compared to station living rooms, turnout gear locker rooms had higher dust levels of total fluorine (p

Particle-induced gamma-ray emission spectroscopy is a quantitative, sensitive technique that measures light element abundance in materials using external reference standards with known beam energy and intensity. When the ion beam is used ex vacuo, gamma-ray spectroscopy on targets in air greatly increases sample throughput. However, for most targets the accuracy of these measurements is limited by the uncertainty of the collected charge. An indirect beam current measurement technique has been developed using an ion beam reaction on atmospheric argon, the only atmospheric component with sufficient abundance (~1%) that produces abundant gamma rays with low-energy proton beams. The 40Ar(p,nγ)40K reaction has been studied here, and the characteristic 770 keV gamma ray is observed to serve as a reliable monitor for proton flux. This method allows a real-time calibration of beam intensity on target to measured upstream currents for ion beam analysis at beam energies above 3.5 MeV.

Elevated blood sera concentrations of perfluorinated and polyfluorinated alkyl substances (PFAS) are associated with many adverse human health effects, including lower birth weight children. Yet th...

Occupational exposure to aqueous film-forming foams (AFFF) can lead to elevated concentrations of per- and polyfluorinated alkyl substances (PFAS) in firefighter blood sera. AFFF are also one expos...

In a broad environmental study in St. Joseph County, Indiana, elemental data from ∼2000 soil samples and ∼800 paint samples were collected with X-ray Fluorescence (XRF) spectroscopy. The observed lead concentrations were compared to other elemental concentrations in these data. A strong correlation between lead and bismuth concentrations was observed in a subset of the soil samples and in nearly all of the paint samples, with lead levels approximately 150 times higher than bismuth. However, some soil samples contained lead with no bismuth present. Since most lead sources likely contain bismuth as an impurity from refining of native lead ore, but leaded gasoline does not contain any bismuth impurities due to the manufacturing process of tetraethyl lead, it may be possible to distinguish environmental lead sources by XRF. To test if leaded gasoline could be the source of lead in the subset of soil samples containing no bismuth, leaded paint samples were analyzed with Inductively Coupled Plasma – Optical Emission Spectroscopy (ICP-OES), which confirmed the presence of bismuth in leaded paint. Aviation gasoline, which contains tetraethyl lead, was also analyzed by ICP-OES to confirm the absence of bismuth in leaded gasoline. This discovery suggests that XRF can be used to rapidly distinguish different legacy lead contamination sources from one another. For low lead concentrations, elemental measurements of bismuth by ICP-OES can be used in environmental forensics to distinguish leaded gasoline contamination from other sources of lead.

Many radioisotopes with potential medical applications are difficult to produce routinely, especially those on the proton-rich side of the valley of stability. Current production methods typically use light-ion (protons or deuteron) reactions on materials of similar mass to the target radioisotope, which limits the elemental target material available and may require the use of targets with poor thermal properties (as is the case for the production of radiobromine). These reactions may also create significant amounts of proton-rich decay products which require chemical separation from the desired product in a highly radioactive environment. A promising alternative method using heavy-ion fusion-evaporation reactions for the production of the medically relevant bromine radioisotopes 76Br (t1/2 = 16.2 h) and 77Br (t1/2 = 57.0 h) is presented. Heavy-ion beams of 28Si and 16O were used to bombard natural chromium and copper targets just above the Coulomb barrier at the University of Notre Dame's Nuclear Science Laboratory to produce these bromine and precursor radioisotopes by fusion-evaporation reactions. Production yields for these reactions were measured and compared to PACE4 calculations. In addition to using more robust targets for irradiation, a simple physical–chemical separation method is proposed that will lead to very high radiopurity yields. A summary of accelerator facility requirements needed for routine production of these radioisotopes is also presented.

Fabric and foam samples from popular children car seats marketed in the United States during 2018 were tested for fluorine content by particle-included gamma ray emission spectroscopy (PIGE, n = 93) and X-ray photoelectron spectroscopy (XPS, n = 36), as well as for per- and polyfluoroalkyl substances (PFAS) by liquid and gas chromatography mass spectrometry (LC/MS and GC/MS, n = 36). PFAS were detected in 97% of the car seat samples analyzed with MS, with total concentrations of 43 PFAS (∑PFAS) up to 268 ng/g. Fabric samples generally had greater ∑PFAS levels than foam and laminated composites of foam and fabric. The three fabric samples with the highest total fluorine content as represented by the highest PIGE signal were also subjected to ultraviolet (UV) irradiation and the total oxidizable precursor (TOP) assay. Results from these treatments, as well as the much higher organofluorine levels measured by PIGE compared to LC/MS and GC/MS, suggested the presence of side-chain fluorotelomer-based polymers (FTPs), which have the potential to readily degrade into perfluoroalkyl acids (PFAAs) under UV light. Furthermore, fluorotelomer (meth)acrylates were found to be indicators for the presence of (meth)acrylate-linked FTPs in consumer products, and thus confirmed that at least half of the tested car seats had FTP-treated fabrics. Finally, extraction of selected samples with synthetic sweat showed that ionic PFAS, particularly those with fluorinated carbons ≤8, can migrate from fabric to sweat, suggesting a potential dermal route of exposure.

Per- and polyfluoroalkyl substances (PFASs) are used in a wide range of consumer products for their water- and grease-resistant properties, but few studies have explored this exposure route. We used multiple regression to investigate associations between six self-reported behaviors hypothesized to influence PFAS exposure and serum concentrations of six PFAS chemicals in 178 middle-aged women enrolled in the Child Health and Development Studies, about half of whom are African American. Blood samples were collected in 2010-2013, and participants were interviewed about behavior in 2015-2016. Results showed that African American women had lower levels of perfluorooctanoic acid (PFOA) and perfluorohexanesulfonic acid (PFHxS) compared with non-Hispanic white women. In African Americans, but not others, frequent consumption of prepared food in coated cardboard containers was associated with higher levels of four PFASs. Flossing with Oral-B Glide, having stain-resistant carpet or furniture, and living in a city served by a PFAS-contaminated water supply were also associated with higher levels of some PFASs. Product testing using particle-induced γ-ray emission (PIGE) spectroscopy confirmed that Oral-B Glide and competitor flosses contained detectable fluorine. Despite the delay between blood collection and interview, these results strengthen the evidence for exposure to PFASs from food packaging and implicate exposure from polytetrafluoroethylene (PTFE)-based dental floss for the first time.

Helitrons are widespread eukaryotic DNA transposons that have significantly contributed to genome variability and evolution, in part because of their distinctive, replicative rolling-circle mechanism, which often mobilizes adjacent genes. Although most eukaryotic transposases form oligomers and use RNase H-like domains to break and rejoin double-stranded DNA (dsDNA), Helitron transposases contain a single-stranded DNA (ssDNA)-specific HUH endonuclease domain. Here, we report the cryo-electron microscopy structure of a Helitron transposase bound to the 5'-transposon end, providing insight into its multidomain architecture and function. The monomeric transposase forms a tightly packed assembly that buries the covalently attached cleaved end, protecting it until the second end becomes available. The structure reveals unexpected architectural similarity to TraI, a bacterial relaxase that also catalyzes ssDNA movement. The HUH active site suggests how two juxtaposed tyrosines, a feature of many replication initiators that use HUH nucleases, couple the conformational shift of an α-helix to control strand cleavage and ligation reactions.

A novel method for radiolabeling perfluorinated alkyl substances (PFAS) with fluorine 18 has been developed, and after purification, the stability and biological distribution in healthy mice were evaluated. Three PFAS, [18F]PFOA (C8), [18F]PFHxA (C6), and [18F]PFBA (C4), were readily labeled and isolated in average yields between 12 and 31%. The stability of each compound was monitored in 0.1% ammonium hydroxide (NH4OH) in methanol, in saline, and in human, mouse, and rat sera. The amount of intact, radiolabeled PFAS was determined by radiometric instant thin layer chromatography and was calculated by the amount of free fluorine 18 observed over time. All compounds were highly stable in 0.1% NH4OH in methanol and saline, with

A novel method for quickly and quantitatively measuring aqueous lead in drinking water has been developed. A commercially available activated carbon felt has been found to effectively capture lead from tap water, and partnered with X-ray fluorescence (XRF) spectrometry, it provides quantitative measurement of aqueous lead in drinking water. Specifically, for a 2 L volume of tap water, the linear range of detection was found to be from 1-150 ppb, encompassing the current EPA limit for lead in drinking water (15 ppb). To make a reproducible and easy to use method for filtering, a 2 L bottle cap with a 1.25 cm diameter hole was used for filtering. Utilizing this filtration method, 75 solutions from 0 to 150 ppb lead gave a 91% sensitivity, 97% specificity, and 93% accuracy, and all the misclassified samples fell between 10 and 15 ppb. This method has also proved reliable for detecting calcium as well as several other divalent metals in drinking water including copper, zinc, iron, and manganese.

Historic industrial activity led to extensive lead and arsenic contamination within residential areas of East Chicago, Indiana, United States. Although remediation is underway, community concerns about this contamination remain. Therefore, the goal for this analysis was to characterize environmental contamination in soil within and around these areas. A total of 228 samples from 32 different sites (addresses) were collected by community members or study staff. These were analyzed for metals using portable x-ray fluorescence or inductively coupled plasma optical emission spectroscopy. Concentrations exceeding EPA screening levels were found for 42% of the soil arsenic samples, 35% of the soil lead samples, and 79% of the soil manganese samples; a few samples also contained elevated copper or zinc. Concentrations above EPA screening levels were identified both within and outside of the formally designated contaminated area. Roughly 30% of all sites had at least one sample above and one sample below the screening level for arsenic, lead, and manganese. For sites within the contaminated area, more than 90% (arsenic), 60% (lead) and 60% (manganese) of the samples exceeded EPA screening levels. There was a significant association of proximity to the historic industrial site with elevated soil concentrations of arsenic and lead; a similar association was present for manganese. These results are consistent with existing data for lead and arsenic and we additionally report elevated concentrations of manganese and a high within-site variability of all metal concentrations. These findings should be considered in future remediation efforts.

While the practice of tattooing has existed for thousands of years, it has recently begun growing in popularity in the US. With the increasing prevalence of tattoos, the methods and inks involved in the tattooing process have also developed. Tattoos now use many brightly colored inks, often made using metal-based pigments. There is concern that chemicals may be present in tattoo inks in concentrations that may lead to human health concerns either during application or removal of tattoos. Since exposure to metals has been linked to tremors, liver damage, memory loss, cognitive loss, and even death, there is concern about the prevalence of metals in tattoo inks in general. To this end, a survey of 226 commercial tattoo inks was performed and each ink was analyzed for the presence of heavy metals using two different x-ray methods: Particle Induced X-Ray Emission and Scanning Electron Microscopy/ Energy Dispersive Spectroscopy. Fifteen metals were identified in various tattoo inks by these rapid x-ray methods, including chromium, manganese, nickel, copper, barium, and lead. Conclusions can be drawn about the prevalence of metals in some pigment colors and from some brands.

Hydroxyapatite is an inorganic mineral closely resembling the mineral phase in bone. However, as a biological mineral, it is highly disordered, and its composition and atomistic structure remain poorly understood. Here, synchrotron X-ray total scattering and pair distribution function analysis methods provide insight into the nature of atomistic disorder in a synthetic bone mineral analogue, chemically substituted hydroxyapatite. By varying the effective hydrolysis rate and/or carbonate concentration during growth of the mineral, compounds with varied degrees of paracrystallinity are prepared. From advanced simulations constrained by the experimental pair distribution function and density functional theory, the paracrystalline disorder prevalent in these materials appears to result from accommodation of carbonate in the lattice through random displacement of the phosphate groups. Though many substitution modalities are likely to occur in concert, the most predominant substitution places carbonate into the mirror plane of an ideal phosphate site. Understanding the mineralogical imperfections of a biologically analogous hydroxyapatite is important not only to potential bone grafting applications but also to biological mineralization processes themselves.

Discarded carpet and clothing are potential sources of per- and polyfluoroalkyl substances (PFASs) in landfill leachate, but little is known about their release when disposed in landfills. The concentrations of 70 PFASs in the aqueous phase of anaerobic model landfill reactors filled with carpet or clothing were monitored under biologically active and abiotic conditions. For carpet, total PFAS release was greater in live than abiotic reactors, with an average of 8.5 nmol/L and 0.62 nmol/L after 552 days, respectively. Release in live carpet reactors was primarily due to 5:3 fluorotelomer carboxylic acid (FTCA - 3.9 nmol/L) and perfluorohexanoic carboxylic acid (PFHxA - 2.9 nmol/L). For clothing, release was more dependent on sample heterogeneity than the presence of biological activity, with 0.63, 21.7, 2.6, and 6.3 nmol/L for two live and two abiotic reactors after 519 days, respectively. Release in the clothing reactors was largely due to perfluorooctatonic carboxylic acid (PFOA), with low relative concentrations of measured biotransformation precursors (FTCAs). For carpet and clothing reactors, the majority of PFAS release was not measured until after day 100. Results demonstrate that carpet and clothing are likely sources of PFASs in landfill leachate.

In this study we examined whether a Gram-positive and a Gram-negative bacterial species have the capability to remove perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) from solution through sorption reactions under two different pH conditions. We developed a novel approach for quantifying PFAS in solution using particle-induced gamma-ray emission (PIGE) spectroscopy, and we used the results to constrain the important PFAS-bacterial sorption mechanisms. A mass balance experiment measuring PFOS in the aqueous phase and solid phase confirmed that PIGE spectroscopy measurements can account for all PFOS in the system, demonstrating for the first time how PIGE spectroscopy can be used to quantify the extent of PFAS sorption in experimental systems. Significant sorption occurred under most conditions studied, with up to 40 ± 5% and 67 ± 11% sorption of PFOA and PFOS, respectively. PFOA and PFOS sorption were both rapid, with steady-state being attained within minutes. PFOS sorption was pH dependent while PFOA sorption was pH independent, and greater sorption occurred onto Bacillus subtilis biomass compared to Pseudomonas putida biomass for both PFAS types. This sorption behavior suggests that pH, the PFAS head molecule, and cell wall structure all have a significant effect on the extent and mechanisms of bacterial sorption of PFAS. The observed sorption behaviors suggest that sorption of both molecules involves electrostatic and hydrophobic components. PFOS desorption was rapid and exhibited complete reversibility for both bacterial species, indicating that sorption is likely a cell surface phenomenon with no internalization occurring on the timescale of these experiments, and that the process can be modeled as an equilibrium reaction. Our work demonstrates that different PFAS molecules react to bacteria differently, and thus likely have markedly different mobilities in the environment. PFAS sorption in geologic systems is strongly influenced by organic matter, and our results suggest that biosorption may represent an inexpensive and effective PFAS remediation technique.

Per- and polyfluoroalkyl substances (PFASs) are highly persistent synthetic chemicals, some of which have been associated with cancer, developmental toxicity, immunotoxicity, and other health effects. PFASs in grease-resistant food packaging can leach into food and increase dietary exposure. We collected ~400 samples of food contact papers, paperboard containers, and beverage containers from fast food restaurants throughout the United States and measured total fluorine using particle-induced γ-ray emission (PIGE) spectroscopy. PIGE can rapidly and inexpensively measure total fluorine in solid-phase samples. We found that 46% of food contact papers and 20% of paperboard samples contained detectable fluorine (>16 nmol/cm2). Liquid chromatography/high-resolution mass spectrometry analysis of a subset of 20 samples found perfluorocarboxylates, perfluorosulfonates, and other known PFASs and/or unidentified polyfluorinated compounds (based on nontargeted analysis). The total peak area for PFASs was higher in 70% of samples (10 of 14) with a total fluorine level of >200 nmol/cm2 compared to six samples with a total fluorine level of

Hazardous chemicals used in electronic and electrical consumer products can re-enter commerce when these products are recycled. The objectives of this study were to 1) identify the possible sources of unexpected chemicals and elements in consumer products, including the use of recycled E-waste plastics and 2) demonstrate bromine detection with nondestructive spectroscopy as an indicator of brominated flame retardants contaminating new products via recycled waste streams. More than 1500 consumer products of diverse types purchased in 2012-2014 were examined using X-ray fluorescence spectroscopy for correlations between bromine and other elements. New electronic products were much more likely than new non-electronics to contain greater than 1000 ppm bromine, consistent with intentionally added flame retardants, while non- electronic products were more likely to contain between 5 and 100 ppm bromine, suggesting unintentional contamination. A typical suite of elements present in E-waste was found in a majority of plastic products. Two product categories, vinyl floor tiles and beaded necklaces/garlands, were explored in more detail. Specific flame retardant chemicals in bead samples were identified by mass spectrometry and their distribution in beads was studied using scanning electron microscopy and energy dispersive spectroscopy. Five brominated chemicals typically used as flame retardants, including BDE-209, were identified in 50 of 50 Mardi Gras beads analyzed.

A novel application of particle-induced X-ray emission (PIXE) has been developed to detect the presence of chlorinated and brominated flame retardant chemicals in polyurethane foams. Traditional Gas Chromatography–Mass Spectrometry (GC–MS) methods for the detection and identification of halogenated flame retardants in foams require extensive sample preparation and data acquisition time. The elemental analysis of the halogens in polyurethane foam performed by PIXE offers the opportunity to identify the presence of halogenated flame retardants in a fraction of the time and sample preparation cost. Through comparative GC–MS and PIXE analysis of 215 foam samples, excellent agreement between the two methods was obtained. These results suggest that PIXE could be an ideal rapid screening method for the presence of chlorinated and brominated flame retardants in polyurethane foams.

Papers and textiles that are treated with per- and polyfluoroalkyl substances (PFASs) are sources of human and environmental exposure. Data for individual PFASs, such as perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA), are not placed into the context of total fluorine for papers and textiles. Gas chromatography–mass spectrometry (GC–MS) and liquid chromatography–tandem mass spectrometry (LC-MS/MS) were used to quantify volatile and ionic PFASs, respectively, and the total oxidizable precursor (TOP) assay was used to quantify precursors that form perfluoroalkyl carboxylates. Molar sums of PFASs obtained by GC-MS, LC-MS/MS, and precursors were compared to total fluorine (nmol F/cm2) determined by particle-induced gamma ray emission (PIGE) spectroscopy, measured before and after extraction. Volatile and ionic PFASs and unknown precursors accounted for 0–2.2%, 0–0.41%, and 0.021–14%, respectively, of the total nmol F/cm2 determined by PIGE. After extraction, papers and textiles retained 64 ± 28%...

Purpose Phosphorus (P) is a limiting nutrient for most US Midwestern aquatic systems and, therefore, increases of P, through point or non-point sources (NPS) of pollution such as agriculture,causeseutrophication. Identifying specific NPS contributions (e.g., upland vs. stream channels) for sediments and P is difficult due to the distributed nature of the pollution. Therefore, studies which link the spatial and temporal aspects of sediment and P transport in these systems can help better characterize the extent of NPS pollution. Materials and methods Our study used fingerprinting techniques to determine sources of sediments in an agricultural watershed (the North Fork of the Pheasant Branch watershed; 12.4 km 2 area) in Wisconsin, USA, during the spring, summer, and fallseasons of2009. Theprimary sources considered were uplands (cultivated fields), stream bank, and streambed. The model used fallout radionuclides, 137 Cs, and 210 Pbxs, along with total P to determine primary sediment sources. A shorter-lived fallout radioisotope, 7 Be, was used to determine the sediment age and percent new sediments in streambed and suspended sediment samples (via the 7 Be/ 210 Pbxs ratio). Results and discussion Upland areas were the primary source of suspended sediments in the stream channels followed by stream banks. The sediment age and percent new sediment for the streambed and suspended sediments showed that the channel contained and transported newer (or more recently tagged with 7 Be) sediments in the spring season (9–131 days sediment age), while relatively old sediments (165–318 days) were moving through the channel system during the fall season. Conclusions Upland areas are the major contributors to instream suspended sediments in this watershed. Sediment resuspension in stream channels could play an important role during the later part of the year. Best management practices should be targeted in the upland areas to reduce the export of sedimentsandsediment-boundPfromagriculturalwatersheds.

At ambient temperatures, a permanent change due to neutron irradiation has been identified in the luminescent properties of the common mineral calcite. Calcite is one of many ubiquitous minerals that are known to exhibit luminescence under electron bombardment, a process known as cathodoluminescence (CL). The UV–Visible spectra of individual calcite grains were measured with CL spectroscopy before and after neutron irradiation. Exposure to neutrons causes additional crystal lattice defects (beyond those naturally-occurring) that leave a permanent, readily-measurable CL signature in the 515 nm region of the spectrum. Dose response results following irradiation have been measured and a spectroscopic signature is described that increases proportionately to neutron dose. The CL measurements are complicated by a dependence on the orientation relative to direction of excitation. When taken into account, the total dose to the crystal can be estimated, and possibly even the direction of the neutron source can be determined. This signature could potentially be developed into a nuclear forensics tool to help identify locations where special nuclear materials have been stored.

A mechanochemical method for the rapid, bulk synthesis of kaolinite has been developed. Metal hydroxides and silicic acid are mechanically ground and hydrothermally treated for as little as a day at 250 °C to produce X-ray pure crystalline materials. This approach has been expanded to allow the synthesis of kaolinites with a portion of the aluminum sites isomorphously substituted with other trivalent metals. The synthetic parameters, such as length of mechanical and hydrothermal treatment, were studied. Products were analyzed by powder X-ray diffraction, attenuated total reflectance infrared spectrometry, scanning electron microscopy, and transmission electron microscopy. The samples exhibited strong order along the c axis and less order along the a and b axes. Trivalent transition and rare earth metals were used to replace aluminum in the structure. These metals included Cr, La, Ce, Pr, Nd, Eu, Gd, Ho, and Er. Cerium (III) substituted kaolinite was successfully synthesized utilizing air-free conditions. This approach allows bulk quantities of substituted kaolinites to be prepared in a relatively short amount of time and offers a new route to synthesize pure and substituted kaolinites that may have novel catalytic properties.

The elemental concentrations of five trace elements in tempered sheet glass fragments were determined using particle-induced X-ray emission (PIXE) spectrometry. The trace element concentrations for calcium, iron, manganese, strontium, and titanium are compared to those obtained by inductively-coupled plasma-atomic emission spectrometry (ICP-AES) following complete digestion by hydrofluoric acid. For these five elements, the absolute concentrations obtained by both methods are shown to agree well over a wide range of concentrations. The limits of detection for trace elements are typically lower for the ICP-AES method. However, we show that the concentrations of these five elements can be accurately measured by the PIXE method. Since PIXE is an entirely non-destructive method, there exists a niche for this technique to be used as a complement to the more sensitive ICP-AES technique in the forensic analysis of sheet glass.

Keywords:forensic science;particle-induced X-ray emission;nondestructive;glass;trace elements;statistical tests Abstract: A procedure has been developed to analyze the trace element concentrations in glass fragments using particle-induced X-ray emission (PIXE) spectrometry. This method involves using accelerated protons to excite inner-shell electronic transitions of target atoms and recording the resultant X-rays to characterize the trace element concentrations. The protocol was able to identify those glass fragments that originated from different sources based on their elemental analyses. The protocol includes specific approaches to calculating uncertainties and handling measurements below the level of detection. The results indicate that this approach has increased sensitivity for several elements with higher atomic number compared with X-ray fluorescence methods. While not as sensitive as laser-ablation or inductively coupled plasma mass spectrometry methods of dissolved samples, it is entirely nondestructive and entails a much simpler sample preparation process that may be used to presort glass fragments for more comprehensive elemental analysis. As such, the technique described may have a niche role in forensic glass analysis.

An absolute measurement of the heavy element concentrations in a dried sample of aqueous protein solution has been combined with the absolute measurement of protein molecular concentration in the same sample. The ratio of these two measurements yields the metal-to-protein compositional stoichiometry of the metalloprotein. This combination of two Ion Beam Analysis techniques (Particle-Induced X-ray Emission and Proton Elastic Scattering Analysis) allows quantitative assessment of the metal atom to protein ratio in metalloproteins without direct measurement of sulfur atoms within the protein for the first time. While these results only demonstrate success with a single well-known metalloprotein, this combination of measurement ratios holds promise for future Ion Beam Analysis studies of metalloproteins.

The adverse effects of metal contamination in sediments require methods that can quickly and accurately assess the extent of environmental pollution. Particle induced X-ray emission spectrometry (PIXE) is demonstrated to be a viable alternative to an established method, which consists of acid digestion and Inductively coupled plasma-optical emission spectrometry (ICP-OES) to measure trace metals in sediment. The analysis of trace metal composition by both techniques on a NIST Standard Reference Material mud gives results that are consistent with the certified values for fourteen measured metals, seven of which are common to both methods. A comparison study conducted on a sediment core from a freshwater lake with a known chromium contamination in Muskegon County, MI also shows a good correlation between the methods for transition metals of environmental interest over a wide range of metal concentrations. Total sample preparation and analysis time for the PIXE measurements is roughly one third that of acid digestion and ICP-OES. Also, the acid digestion step does not elute all the metal, while the nondestructive PIXE approach is a total metals analysis method. However the PIXE method generally has higher limits of detection for many environmental metal contaminants. By combining the two techniques, the acid digestion elution factor can be quantified by running PIXE on an original sample and on the residue resulting from acid digestion.

Isotope harvesting is a promising new method to obtain isotopes for which there is no reliable continuous supply at present. To determine the possibility of obtaining radiochemically pure radioisotopes from an aqueous beam dump at a heavy-ion fragmentation facility, preliminary experiments were performed to chemically extract a copper isotope from a large mixture of projectile fragmentation products in an aqueous medium. In this work a 93 MeV/u secondary beam cocktail was collected in an aqueous beam stop at the National Superconducting Cyclotron Laboratory (NSCL) located on the Michigan State University (MSU) campus. The beam cocktail consisted of ∼2.9% (67)Cu in a large mixture of co-produced isotopes ranging in atomic number from ∼19 to 34. The chemical extraction of (67)Cu was achieved via a two-step process: primary extraction using a divalent metal chelation disk followed by anion-exchange chromatography. A significant fraction (74 ± 4%) of the (67)Cu collected in the aqueous beam stop was recovered with99% radiochemical purity. To illustrate the utility of this product, the purified (67)Cu material was then used to radiolabel an anti-EGFR antibody, Panitumumab, and injected into mice bearing colon cancer xenografts. The tumor uptake at 5 days postinjection was found to be 12.5 ± 0.7% which was in very good agreement with previously reported studies with this radiolabeled antibody. The present results demonstrate that harvesting isotopes from a heavy-ion fragmentation facility could be a promising new method for obtaining high-quality isotopes that are not currently available by traditional methods.

Spectroscopy of neutron rich exotic isotopes via their isobaric analog states (IAS) in less exotic nuclei is discussed. Several different experimental techniques, which can be applied to search for IAS of exotic isotopes, are described. Successful application of these techniques to the studies of heavy helium isotopes 7 He and 9 He led to the observation of unknown IAS in 7 Li and 9 Li. Spectroscopic information for these states were obtained, and implication of these findings to the structure of 7,9 He is considered.

Environmental Health Perspectives, 123 (5), ISSN:1552-9924, ISSN:0091-6765

Environmental Health Perspectives, 123 (7), ISSN:1552-9924, ISSN:0091-6765

There are many isotopes that could be useful in a range of disciplines from medicine to stockpile stewardship, geology, nuclear astrophysics and biology that are not available in the quantities needed from conventional production methods based on small medical cyclotrons or reactors1,2,3,4,5,6,7. The construction of the Facility for Rare Isotope Beams (FRIB) will allow “harvesting” usable quantities of many of these isotopes, concurrent with secondary-beam operations for basic nuclear science experiments. The FRIB design has provisions for delivering research quantities (μCi to Ci) of radioisotopes as an ancillary service to the on-line experimental program by collecting radioisotopes produced or stopped in an aqueous beam dump8,9 in the primary target facility while secondary beams are produced for on-line experiments. Ideally this collection or “harvesting” of isotopes at FRIB could provide isotopic material for which there is currently no comparable source. One such radioisotope is 67Cu which can be used in medicine as a therapeutic isotope6,10,11. Its relatively long 2.58 day half-life is ideal for labeling antibodies that also have several-day biological half-lives. Obtaining therapeutic doses that are typically on the order of hundreds of mCi/patient12 has proved to be quite difficult due to inconsistent production and no reliable continuous supply6,12,13,14. 67Cu can be made via several nuclear reactions: 68Zn(p,2p)67Cu, 70Zn(p,α)67Cu, 67Zn(n,p)67Cu, and 68Zn(γ,p)67Cu; however each reaction has practical drawbacks. For example, 68Zn(p,2p)67Cu has a low but broad (in energy) cross section and in order to efficiently produce the large quantities needed for therapeutic doses thick targets and high-energy proton accelerators such as those at Brookhaven15,16 or Los Alamos National Laboratories17 need to be employed. These are multiuser facilities that cannot routinely dedicate proton beam to produce a continuous supply of 67Cu12. Studies at several facilities of the 70Zn(p,α)67Cu reaction have obtained varying yields and the production of the large quantities needed for therapeutic studies are challenging with this method18,19,20. Production via the 67Zn(n,p)67Cu and 68Zn(γ,p)67Cu reactions have undesirable side reactions and concerns about waste products create challenges for their large scale use12. It is estimated that FRIB will be able to produce a saturated activity of 67Cu as high as ~2 Ci depending on the primary beam21 so that weekly harvesting of 67Cu could provide a more consistent supply of this isotope. Therefore, given the difficulty of other production methods, the favorable half-life and well-understood chemistry of 67Cu, this isotope was selected for a proof-of-principle test of isotope harvesting from an aqueous beam stop for projectile fragments. The work reported here can be extended to other projectile fragments collected in an aqueous beam stop. Previously, a liquid-water target system/beam stop was designed and tested at the NSCL for a first attempt to harvest useful radioisotopes from a beam dump similar to what will exist at FRIB22. This system was used successfully to collect several samples of 24Na from a projectile fragment beam at ~85 MeV/u and an intensity of ~2 × 106 pps. In the present work, the liquid water target system described in ref [8] was used to collect several samples of 67Cu that were also produced as a secondary beam at the NSCL. The aqueous samples were then transported to Washington University in St Louis, MO and Hope College in Holland, MI for chemical separation, antibody labeling, and offline counting. We report here the results of these studies and the observation of relatively high chemical extraction efficiency.

This paper presents the results of our investigations on the gas sensing performance of Pt/TiO2/SiC based field effect devices. The current–voltage characteristics of these Pt/TiO2/SiC sensors at 530 °C showed a clear shift to lower voltages upon exposure to increasing hydrogen gas concentration. This indicates a reduction in the metal-oxide interface barrier height, arising from the flattening of the energy bands at the interface and can be attributed to the lowering of the Pt work function due to absorption of hydrogen. The effective change in barrier height Δφb for 1% hydrogen in air was found to be 125 meV. The thermal stability of the interfaces in the Pt/TiO2/SiC devices was studied by Rutherford backscattering spectrometry (RBS). The RBS spectra of the sample in as deposited and annealed conditions were compared and analyzed. The Pt/TiO2 and TiO2/SiC layers showed a sharp interface with minimal inter-diffusion. The film composition found to be stable even after repeated testing by exposing to analyte gases. This was further confirmed by X-ray photoelectron spectroscopy analysis of the samples.

Platinum electrodes were chemically modified with tris(5-amino-1,10-phenanthroline) ruthenium(II) via electropolymerization. The characterization of the thin films was accomplished with cyclic voltammetry (CV) and Rutherford Backscattering Spectrometry (RBS). Data indicates a strong correlation between the peak currents from the characterization cyclic voltammograms and the number of cycles of electropoly-merization. Rutherford Backscattering Spectrometry showed the same trend, and verified that film thickness is strongly dependent on the concentration of the monomer ruthenium solution. Film thickness was determined from the change in ion beam energy as it passed through the film and was calculated to be 1.0 x 1018 atoms/cm2 – 3.4 x 1018 atoms/cm2, depending upon the number of electropolymerization cycles. The electrodes also showed differences in surface roughness, which were dependent on film thickness.

The elemental composition of electrodeposited NiFe thin films was analyzed with particle-induced X-ray emission (PIXE). The thin films were electrodeposited on polycrystalline Au substrates from a 100 mM NiSO4, 10 mM FeSO4, 0.5 M H3BO3, and 1 M Na2SO4solution. PIXE spectra of these films were analyzed to obtain relative amounts of Ni and Fe as a function of deposition potential and deposition time. The results show that PIXE can measure the total deposited metal in a sample over at least four orders of magnitude with similar fractional uncertainties. The technique is also sensitive enough to observe the variations in alloy composition due to sample nonuniformity or variations in deposition parameters.

Collisions between 36Ar projectiles and 197Au target nuclei at E A = 50, 80 and 110 MeV have been studied with the MSU Miniball, a 4π phoswich array with a low detection threshold. Various impact-parameter filters, based upon total charged-particle multiplicity, transverse energy, midrapidity charge and multiplicity of emitted hydrogen nuclei, are compared and cross-correlated. The relative selectivity of each prescription for small impact-parameter collisions is evaluated by assessing the suppression of fast-particle emission at forward angles.

We report on a new methods for studies of neutron rich systems through resonant (p,n) reaction with radioactive ion beams. A specific example of the spectroscopy of 7He and future application of the proposed methods are discussed.

Glassy carbon electrodes modified with (5-amino-1,10-phenanthroline)bis(bipyridine)ruthium(II) chloride hydrate, [(bpy)2Ru(5-phenNH2)]Cl2·H2O, are shown to oxidize hydrazine with excellent sensitivity. The presence of an amine group on the ruthenium complex facilitates electropolymerization onto the electrode surface. Using cyclic voltammetry, a large catalytic current is observed upon oxidation of hydrazine in phosphate buffer (pH 5.0), compared to the current obtained from the ruthenium-modified electrode with no hydrazine present. The sensitivity of cyclic voltammetry is sufficient for obtaining a linear calibration curve for hydrazine over the range of 10−5 to 10−2 M. Hydrodynamic amperometry was used to determine the working potential for flow injection analysis. The limit of detection for hydrazine was determined to be 8.5 μM using FIA. The thickness of these films was shown to increase linearly with the number of electropolymerization cycles, in the range of 1000–2500 nm for 5–20 cycles, respectively, using Rutherford backscattering spectrometry (RBS). RBS analysis also suggests that the film is multilayered with the outermost layers containing a high ruthenium concentration, followed by layers where the concentration of ruthenium decreases linearly and approaches zero at the electrode surface.

The growth of accelerator mass spectrometry as a tool for quantitative isotope ratio analysis in the biosciences necessitates high-throughput sample preparation. A method has been developed to convert CO(2) obtained from carbonaceous samples to solid graphite for highly sensitive and precise (14)C quantification. Septa-sealed vials are used along with commercially available disposable materials, eliminating sample cross contamination, minimizing complex handling, and keeping per sample costs low. Samples containing between 0.25 and 10 mg of total carbon can be reduced to graphite in approximately 4 h in routine operation. Approximately 150 samples per 8-h day can be prepared by a single technician.

The ensemble of charged isotropically emitted ejectiles is studied for central collisions of $(17\ensuremath{-}115)A$ MeV ${}^{40}\mathrm{Ar}\mathrm{}+\mathrm{}\mathrm{Cu},$ Ag, Au. Measurements of average multiplicities, spectral slopes, and masses of the heaviest fragments are compared to statistical models for multifragmentation or sequential evaporation. The multifragmentation models predict much more complete nuclear disassembly than is observed. The evaporation model reproduces the data much more closely except for the spectra of $Z=1$ ejectiles. The kinetic energies of $Z=1$ and 2 ejectiles are much less than found for $1A$ GeV ${}^{197}\mathrm{Au}{+}^{12}\mathrm{C}$ for similar energy depositions. Entrance channel dynamics seem to affect the isotropic emission ensembles, often taken to define an equilibrated emission source.

The Hope College PIXE facility was used to perform an analysis of zircons, apatites and monazites prevalent in rocks collected in southern India. Thin sections of the samples were prepared for electron microprobe analysis at U. Chicago, and a number of rare earth elements were quantitatively measured. These samples were then fractured and individual crystals were analyzed with 2.3 MeV protons in an internal PIXE irradiation chamber. GUPIX II© software was used to identify and measure trace metals in the samples and the results have been correlated with the electron microprobe data. Whole rock analyses, prepared by making pressed pellets of the powdered rock components were also analyzed by PIXE and XRF. Each of these techniques can be used to address the geological distribution of large ion lithophiles in the mantle, and advantages and disadvantages of each technique will be presented.

Multifragment decays of central collisions in ${}^{84}\mathrm{Kr}{+}^{197}\mathrm{Au}$ at $E/A\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}70\mathrm{MeV}$ are studied. By utilizing a technique sensitive to the emission order of fragments, it is deduced that carbon fragments are emitted prior to beryllium fragments when these fragments have the same velocity. This observation is consistent with the cooling of a thermally decaying source.

A new, sensitive method allows one to search for the enhancement of events with nearly equal-sized fragments as predicted by theoretical calculations based on volume or surface instabilities. Simulations have been performed to investigate the sensitivity of the procedure. Experimentally, charge correlations of intermediate mass fragments emitted from heavy ion reactions at intermediate energies have been studied. No evidence for a preferred breakup into equal-sized fragments has been found., Comment: 12 pages, TeX type, psfig, submitted to Phys. Rev. Lett, also available at http://csa5.lbl.gov/moretto/ps/zcor_pp.ps

Position-sensitive silicon detectors with discrete position output signal levels, which have been developed for heavy ion reaction studies at the Lawrence Berkeley Laboratory are discussed. The detectors, both 300- and 5000- mu m thick, for use in Delta E-E telescopes, use a series of high and low conductivity strips on the detector p/sup +/ contact to produce a position signal with 15 discrete levels. Since the position of the signals from the strips is known, the detectors are self-calibrating against position nonlinearities. Some aspects of the fabrication of both the 300- and 5000- mu m detectors are discussed, along with their operating characteristics. Illustrative experimental results of /sup 139/La-induced reactions on /sup 40/Ca targets are presented. >