Development of two fine particulate matter standard reference materials (<4 µm and <10 µm) for the determination of organic and inorganic constituents.

Two new Standard Reference Materials (SRMs), SRM 2786 Fine Particulate Matter (<4 µm) and SRM 2787 Fine Particulate Matter (<10 µm) have been developed in support of the US Environmental Protection Agency's National Ambient Air Quality Standards for particulate matter (PM). These materials have been characterized for the mass fractions of selected polycyclic aromatic hydrocarbons (PAHs), nitrated PAHs, brominated diphenyl ether (BDE) congeners, hexabromocyclododecane (HBCD) isomers, sugars, polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners, and inorganic constituents, as well as particle-size characteristics. These materials are the first Certified Reference Materials available to support measurements of both organic and inorganic constituents in fine PM. In addition, values for PAHs are available for RM 8785 Air Particulate Matter on Filter Media. As such, these SRMs will be useful as quality control samples for ensuring compatibility of results among PM monitoring studies and will fill a void to assess the accuracy of analytical methods used in these studies. Graphical Abstract Removal of PM from filter for the preparation of SRM 2786 Fine Particulate Matter.

Splinting and hand exercise for three common hand deformities in rheumatoid arthritis: a clinical perspective.

PURPOSE OF REVIEW: Hand deformities (ulnar drift, swan neck and boutonniere) are prevalent in rheumatoid arthritis and develop early in the disease process. These deformities cause significant functional impairment and impact quality of life. This review will provide a clinical perspective using the most recent evidence regarding the role of splinting and hand exercise in their management. The pathomechanics and functional consequences of these deformities are also described. RECENT FINDINGS: Patients tend to under-report their hand problems and are often reluctant to seek treatment for their deformities. There is limited evidence to support or refute the role of splinting and hand exercises in their management. Clinical experience suggests splinting and hand exercise are most beneficial when prescribed for early, flexible deformities. SUMMARY: More research is required to guide clinicians on the most effective approach to the management of these three hand deformities. It is imperative that clinicians assess for and recognize these deformities in order to ensure timely and appropriate treatment. Until more evidence becomes available, an evidenced-informed approach is recommended.

Characterization of three berry standard reference materials for nutrients.

The National Institute of Standards and Technology (NIST) has been working with the National Institutes of Health Office of Dietary Supplements to produce Standard Reference Materials (SRMs) of interest to analysts of dietary supplements. Some of these SRMs are traditional foods including SRM 3281 Cranberry (Fruit), SRM 3282 Low-Calorie Cranberry Juice Cocktail, and SRM 3287 Blueberry (Fruit), which have been characterized for nine nutritional elements and sugars. The blueberries have also been characterized for proximates, two water-soluble vitamins, and amino acids. These new materials are intended for use in method development and validation as well as for quality assurance and traceability in the assignment of values to in-house control materials. Foods can be difficult to analyze because of matrix effects. With the addition of these three new SRMs, it is now possible to more closely match controls to matrices and analyte levels for fruit and vegetable test samples. Several nutritional elements in these three SRMs are present at lower levels than in other food-matrix SRMs.

Marine mammal blubber reference and control materials for use in the determination of halogenated organic compounds and fatty acids.

The National Institute of Standards and Technology (NIST) has a diverse collection of control materials derived from marine mammal blubber, fat, and serum. Standard Reference Material (SRM) 1945 Organics in Whale Blubber was recertified for polychlorinated biphenyl (PCB) congeners, organochlorine pesticides, and polybrominated diphenyl ether (PBDE) congeners. SRM 1945 has also been assigned mass fraction values for compounds not frequently determined in marine samples including toxaphene congeners, coplanar PCBs, and methoxylated PBDE congeners which are natural products. NIST also has assigned mass fraction values, as a result of interlaboratory comparison exercises, for PCB congeners, organochlorine pesticides, PBDE congeners, and fatty acids in six homogenate materials produced from marine mammal blubber or serum. The materials are available from NIST upon request; however, the supply is very limited for some of the materials. The materials include those obtained from pilot whale blubber (Homogenates III and IV), Blainville's beaked whale blubber (Homogenate VII), polar bear fat (Homogenate VI), and California sea lion serum (Marine Mammal Control Material-1 Serum) and blubber (Homogenate V).

Separation of 26 toxaphene congeners and measurement in air particulate matter SRMs compared to technical toxaphene SRM 3067.

Toxaphene is a complex technical mixture that has been found ubiquitously in the environment but has caused issues for analysis, especially of individual congeners. This paper reports the elution order of 26 major toxaphene congeners on three gas chromatographic columns. The three different stationary phases generally had similar elution orders for the toxaphene congeners, but fewer co-elutions occurred on a low-bleed, low-polarity column. These congeners (except for two that co-eluted and were not added to the calibration mixture) were examined in air particulate matter standard reference materials (SRMs), 1648a, 1649a, and 1649b as well as SRM 3067 toxaphene in methanol for assignment of reference values. SRM 3067 had mass fractions an order of magnitude greater than the air particulate SRMs, which ranged from 0.568 +/- 0.018 ng g(-1) dry mass (B9-2006 in SRM 1648a) to 12.9 +/- 0.20 ng g(-1) dry mass (B9-715 (P 58) in SRM 1649a). The three air particulate SRMs all had different mass fractions and proportions of congeners relative to the sum of the toxaphene congeners. SRM 3067 may be useful as a technical mixture toxaphene congener calibrant. SRMs 1648a and 1649b will serve as reference materials for the analysis of 21 (three congeners were not included due to values below the detection limit or a potential polychlorinated biphenyl co-elution) toxaphene congeners in atmospheric particulate samples.

Development of saw palmetto (Serenoa repens) fruit and extract standard reference materials.

As part of a collaboration with the National Institutes of Health's Office of Dietary Supplements and the Food and Drug Administration's Center for Drug Evaluation and Research, the National Institute of Standards and Technology has developed two standard reference materials (SRMs) representing different forms of saw palmetto (Serenoa repens), SRM 3250 Serenoa repens fruit and SRM 3251 Serenoa repens extract. Both of these SRMs have been characterized for their fatty acid and phytosterol content. The fatty acid concentration values are based on results from gas chromatography with flame ionization detection (GC-FID) and mass spectrometry (GC/MS) analysis while the sterol concentration values are based on results from GC-FID and liquid chromatography with mass spectrometry analysis. In addition, SRM 3250 has been characterized for lead content, and SRM 3251 has been characterized for the content of beta-carotene and tocopherols. SRM 3250 (fruit) has certified concentration values for three phytosterols, 14 fatty acids as triglycerides, and lead along with reference concentration values for four fatty acids as triglycerides and 16 free fatty acids. SRM 3251 (extract) has certified concentration values for three phytosterols, 17 fatty acids as triglycerides, beta-carotene, and gamma-tocopherol along with reference concentration values for three fatty acids as triglycerides, 17 fatty acids as free fatty acids, beta-carotene isomers, and delta-tocopherol and information values for two phytosterols. These SRMs will complement other reference materials currently available with concentrations for similar analytes and are part of a series of SRMs being developed for dietary supplements.

Hexabromocyclododecane in white-sided dolphins: temporal trend and stereoisomer distribution in tissues.

Hexabromocyclododecane (HBCD) is a brominated flame retardant used primarily in expanded polystyrene foams and other styrene resins. Samples of blubber (n = 57) and liver (n = 16) from Atlantic white-sided dolphins, Lagenorhynchus acutus, that stranded on the eastern coast of United States between 1993 and 2004 were obtained from the National Marine Mammal Tissue Bank (NMMTB). Blubber samples from most of these animals (n = 47) were previously analyzed for polybrominated diphenyl ethers (PBDE), polychlorinated biphenyls (PCB), and several toxaphene congeners. The three most abundant diastereomers in the technical HBCD mixture (alpha-HBCD, beta-HBCD, and gamma-HBCD) and their enantiomers were determined using liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS). alpha-HBCD was found in all blubber and liver samples while beta-HBCD and gamma-HBCD were not detected in any samples. The alpha-HBCD concentration in blubber and liver ranged from 14 ng/g wet mass (19 ng/g lipid) to 280 ng/g wet mass (380 ng/g lipid) and 0.051 ng/g wet mass (2.9 ng/g lipid) to 3.6 ng/g wet mass (140 ng/g lipid), respectively. Concentrations of alpha-HBCD were 2 to 3 orders of magnitude lower than previously reported PBDE, PCB, and toxaphene concentrations in these same animals. There was not a significant temporal trend for these compounds in white-sided dolphin blubber. The enantiomeric fractions (EF) measured in blubber and liver were not statistically different and ranged from 0.34 to 0.53. Blubber EFs were significantly correlated with both alpha-HBCD concentrations and white-sided dolphin body length. In general, concentrations of HBCDs were lower in these white-sided dolphins than in cetaceans from Western Europe.

Characterization of a suite of ginkgo-containing standard reference materials.

A suite of three ginkgo-containing dietary supplement Standard Reference Materials (SRMs) has been issued by the National Institute of Standards and Technology (NIST) with certified values for flavonoid aglycones, ginkgolides, bilobalide, and selected toxic trace elements. The materials represent a range of matrices (i.e., plant, extract, and finished product) that provide different analytical challenges. The constituents have been determined by at least two independent analytical methods with measurements performed by NIST and at least one collaborating laboratory. The methods utilized different extractions, chromatographic separations, modes of detection, and approaches to quantitation. The SRMs are primarily intended for method validation and for use as control materials to support the analysis of dietary supplements and related botanical materials.

Development and application of an ultratrace method for speciation of organotin compounds in cryogenically archived and homogenized biological materials.

An accurate, ultra-sensitive and robust method for speciation of mono, di, and tributyltin (MBT, DBT, and TBT) by speciated isotope-dilution gas chromatography-inductively coupled plasma-mass spectrometry (SID-GC-ICPMS) has been developed for quantification of butyltin concentrations in cryogenic biological materials maintained in an uninterrupted cryo-chain from storage conditions through homogenization and bottling. The method significantly reduces the detection limits, to the low pg g(-1) level (as Sn), and was validated by using the European reference material (ERM) CE477, mussel tissue, produced by the Institute for Reference Materials and Measurements. It was applied to three different cryogenic biological materials-a fresh-frozen mussel tissue (SRM 1974b) together with complex materials, a protein-rich material (whale liver control material, QC03LH03), and a lipid-rich material (whale blubber, SRM 1945) containing up to 72% lipids. The commutability between frozen and freeze-dried materials with regard to spike equilibration/interaction, extraction efficiency, and the absence of detectable transformations was carefully investigated by applying complementary methods and by varying extraction conditions and spiking strategies. The inter-method results enabled assignment of reference concentrations of butyltins in cryogenic SRMs and control materials for the first time. The reference concentrations of MBT, DBT, and TBT in SRM 1974b were 0.92 +/- 0.06, 2.7 +/- 0.4, and 6.58 +/- 0.19 ng g(-1) as Sn (wet-mass), respectively; in SRM 1945 they were 0.38 +/- 0.06, 1.19 +/- 0.26, and 3.55 +/- 0.44 ng g(-1), respectively, as Sn (wet-mass). In QC03LH03, DBT and TBT concentrations were 30.0 +/- 2.7 and 2.26 +/- 0.38 ng g(-1) as Sn (wet-mass). The concentration range of butyltins in these materials is one to three orders of magnitude lower than in ERM CE477. This study demonstrated that cryogenically processed and stored biological materials are a promising alternative to conventional freeze-dried materials for organotin speciation analysis, because these are, at present, the best conditions for minimizing degradation of thermolabile species and for long-term archival. Finally, the potential of the analytical method was illustrated by analysis of polar bear (Ursus maritimus) and beluga whale (Delphinapterus leuca) liver samples that had been collected in the Arctic and archived at the Marine Environmental Specimen Bank. Significant concentrations of butyltin compounds were found in the samples and provide the first evidence of the presence of this class of contaminant in the Arctic marine ecosystem. Figure Eye catch image.

Certification of methylmercury content in two fresh-frozen reference materials: SRM 1947 Lake Michigan fish tissue and SRM 1974b organics in mussel tissue (Mytilus edulis).

This paper describes the development of two independent analytical methods for the extraction and quantification of methylmercury from marine biota. The procedures involve microwave extraction, followed by derivatization and either headspace solid-phase microextraction (SPME) with a polydimethylsiloxane (PDMS)-coated silica fiber or back-extraction into iso-octane. The identification and quantification of the extracted compounds is carried out by capillary gas chromatography/mass spectrometric (GC/MS) and inductively coupled plasma mass spectrometric (GC/ICP-MS) detection. Both methods were validated for the determination of methylmercury (MeHg) concentrations in a variety of biological standard reference materials (SRMs) including fresh-frozen tissue homogenates of SRM 1946 Lake Superior fish tissue and SRM 1974a organics in mussel tissue (Mytilus edulis) and then applied to the certification effort of SRM 1947 Lake Michigan fish tissue and SRM 1974b organics in mussel tissue (Mytilus edulis). While past certifications of methylmercury in tissue SRMs have been based on two independent methods from the National Institute of Standards and Technology (NIST) and participating laboratories, the methods described within provide improved protocols and will allow future certification efforts to be based on at least two independent analytical methods within NIST.

Persistent organic pollutants in Alaskan ringed seal (Phoca hispida) and walrus (Odobenus rosmarus) blubber.

Since 1987, the Alaska Marine Mammal Tissue Archival Project (AMMTAP) has collected tissues from 18 marine mammal species. Specimens are archived in the National Institute of Standards and Technology's National Biomonitoring Specimen Bank (NIST-NBSB). AMMTAP has collected blubber, liver and/or kidney specimens from a number of ringed seals (Phoca hispida) from the areas near Nome and Barrow, Alaska and walruses (Odobenus rosmarus) from several locations in the Bering Sea. Thirty-three ringed seal and 15 walrus blubber samples from the NIST-NBSB were analyzed for persistent organic pollutants (POPs). The compounds determined included PCBs (28 congeners or congener groups), DDT and related compounds, hexachlorobenzene (HCB), hexachlorocyclohexane isomers (HCHs), chlordanes, dieldrin, and mirex. POP concentrations in ringed seal blubber were significantly higher in Barrow than in Nome when statistically accounting for the interaction of age and gender; HCB, however, was not statistically different between the two locations. Unlike males, POP concentrations and age were not significantly correlated in females probably as a result of lactational loss. POP concentrations in walrus blubber were lower than in ringed seal blubber for SigmaPCBs, chlordanes, and HCHs, but higher for dieldrin and mirex. POP concentrations in ringed seals and walrus from Alaska provide further evidence that the western Arctic tends to have lower or similar POP concentrations compared to the eastern Canadian Arctic.

Preparation and characterization of a suite of ephedra-containing standard reference materials.

The National Institute of Standards and Technology, the U.S. Food and Drug Administration, Center for Drug Evaluation and Research and Center for Food Safety and Applied Nutrition, and the National Institutes of Health, Office of Dietary Supplements, are collaborating to produce a series of Standard Reference Materials (SRMs) for dietary supplements. A suite of ephedra materials is the first in the series, and this paper describes the acquisition, preparation, and value assignment of these materials: SRMs 3240 Ephedra sinica Stapf Aerial Parts, 3241 E. sinica Stapf Native Extract, 3242 E. sinica Stapf Commercial Extract, 3243 Ephedra-Containing Solid Oral Dosage Form, and 3244 Ephedra-Containing Protein Powder. Values are assigned for ephedrine alkaloids and toxic elements in all 5 materials. Values are assigned for other analytes (e.g., caffeine, nutrient elements, proximates, etc.) in some of the materials, as appropriate. Materials in this suite of SRMs are intended for use as primary control materials when values are assigned to in-house (secondary) control materials and for validation of analytical methods for the measurement of alkaloids, toxic elements, and, in the case of SRM 3244, nutrients in similar materials.

Determination of caffeine, theobromine, and theophylline in standard reference material 2384, baking chocolate, using reversed-phase liquid chromatography.

A rapid and selective isocratic reversed-phase liquid chromatographic method has been developed at the National Institute of Standards and Technology to simultaneously measure caffeine, theobromine, and theophylline in a food-matrix standard reference material (SRM) 2384, Baking Chocolate. The method uses isocratic elution with a mobile phase composition (volume fractions) of 10% acetronitrile/90% water (pH adjusted to 2.5 using acetic acid) at a flow rate of 1.5 mL/min with ultraviolet absorbance detection (274 nm). Total elution time for these analytes is less than 15 min. Concentration levels of caffeine, theobromine, and theophylline were measured in single 1-g samples taken from each of eight bars of chocolate over an eight-day period. Samples were defatted with hexane, and beta-hydroxyethyltheophylline was added as the internal standard. The repeatability for the caffeine, theobromine, and theophylline measurements was 5.1, 2.3, and 1.9%, respectively. The limit of quantitation for all analytes was <100 ng/mL. The measurements from this method were used in the value-assignment of caffeine, theobromine, and theophylline in SRM 2384.

Three new mussel tissue standard reference materials (SRMs) for the determination of organic contaminants.

Three new mussel tissue standard reference materials (SRMs) have been developed by the National Institute of Standards and Technology (NIST) for the determination of the concentrations of organic contaminants. The most recently prepared material, SRM 1974b, is a fresh frozen tissue homogenate prepared from mussels ( Mytilus edulis) collected in Boston Harbor, Massachusetts. The other two materials, SRMs 2977 and 2978, are freeze-dried tissue homogenates prepared from mussels collected in Guanabara Bay, Brazil and Raritan Bay, New Jersey, respectively. All three new mussel tissue SRMs complement the current suite of marine natural-matrix SRMs available from NIST that are characterized for a wide range of contaminants (organic and inorganic). SRM 1974b has been developed to replace its predecessor SRM 1974a, Organics in Mussel Tissue, for which the supply is depleted. Similarly, SRMs 2977 and 2978 were developed to replace a previously available (supply depleted) freeze-dried version of SRM 1974a, SRM 2974, Organics in Freeze-Dried Mussel Tissue. SRM 1974b is the third in a series of fresh frozen mussel tissue homogenate SRMs prepared from mussels collected in Boston Harbor starting in 1988. SRM 1974b has certified concentration values for 22 polycyclic aromatic hydrocarbons (PAHs), 31 polychlorinated biphenyl congeners (PCBs), and 7 chlorinated pesticides. Reference values are provided for additional constituents: 16 PAHs, 8 PCBs plus total PCBs, 6 pesticides, total extractable organics, methylmercury, and 11 trace elements. PAH concentrations range from about 2 ng g(-1 )dry mass (cyclopenta[ cd]pyrene) to 180 ng g(-1 )dry mass (pyrene). PCB concentrations range from about 2 ng g(-1 )dry mass (PCB 157) to 120 ng g(-1 )dry mass (PCB 153). The reference value for total PCBs in SRM 1974b is (2020 +/- 420) ng g(-1 )dry mass. Pesticide concentrations range from about 4 ng g(-1 )dry mass (4,4'-DDT) to 40 ng g(-1 )dry mass (4,4'-DDE). SRM 2977 has certified values for 14 PAHs, 25 PCB congeners, 7 pesticides, 6 trace elements, and methylmercury. Reference values for 16 additional PAHs and 9 inorganic constituents are provided, and information values are given for 23 additional trace elements. SRM 2978 has certified and reference concentrations for 41 and 22 organic compounds, respectively, and contains contaminant levels similar to those of SRM 1974b. Organic contaminant levels in SRM 2977 (mussels from Guanabara Bay, Brazil) are typically a factor of 2 to 4 lower than those in SRM 1974b and SRM 2978. The organic contaminant concentrations in each new mussel tissue SRM are presented and compared in this paper. In addition, a chronological review of contaminant concentrations associated with mussels collected in Boston Harbor is discussed as well as a stability assessment of SRM 1974a.

Two new marine sediment standard reference materials (SRMs) for the determination of organic contaminants.

Two new marine sediment standard reference materials (SRMs), SRM 1941b Organics in Marine Sediment and SRM 1944 New York/New Jersey Waterway Sediment, have been recently issued by the National Institute of Standards and Technology (NIST) for the determination of organic contaminants including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyl (PCB) congeners, and chlorinated pesticides. Both sediment SRMs were analyzed using multiple analytical methods including gas chromatography/mass spectrometry (GC/MS) on columns with different selectivity, reversed-phase liquid chromatography with fluorescence detection (for PAHs only), and GC with electron capture detection (for PCBs and pesticides only). SRM 1941b has certified concentrations for 24 PAHs, 29 PCB congeners, and 7 pesticides, and SRM 1944 has certified concentrations for 24 PAHs, 29 PCB congeners, and 4 pesticides. Reference concentrations are also provided for an additional 58 (SRM 1941b) and 39 (SRM 1944) PAHs, PCB congeners, and pesticides. SRM 1944, which was collected from multiple sites within New York/New Jersey coastal waterways, has contaminant concentrations that are generally a factor of 10-20 greater than SRM 1941b, which was collected in the Baltimore (Maryland) harbor. These two SRMs represent the most extensively characterized marine sediment certified reference materials available for the determination of organic contaminants.

Determination of polychlorinated biphenyl congeners and chlorinated pesticides in a fish tissue standard reference material.

The concentrations of a wide range of polychlorinated biphenyl congeners (PCBs) and chlorinated pesticides in a fish tissue Standard Reference Material (SRM) have been determined using multiple methods of analysis. This material, SRM 1946, Lake Superior Fish Tissue, was recently issued by the National Institute of Standards and Technology (NIST) and complements a suite of marine environmental natural-matrix SRMs that are currently available from NIST for the determination of organic contaminants such as aliphatic hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), PCBs, and chlorinated pesticides. SRM 1946 is a fresh tissue homogenate (frozen) prepared from filleted adult lake trout (Salvelinus namaycush namaycush) collected from the Apostle Islands region of Lake Superior. SRM 1946 has certified and reference concentrations for PCB congeners, including the three non- ortho PCB congeners, and chlorinated pesticides. Certified concentrations are available for 30 PCB congeners and 15 chlorinated pesticides. Reference concentrations are available for 12 PCB congeners and 2 chlorinated pesticides. In addition, SRM 1946 is characterized for additional chemical constituents and properties: fatty acids, extractable fat, methylmercury, total mercury, selected trace elements, proximates, and caloric content. The characterization of chlorinated compounds is described in this paper with an emphasis on the approach used for the certification of the concentrations of PCB congeners and chlorinated pesticides. The PCB congener and chlorinated pesticide data are also compared to concentrations in other marine natural-matrix reference materials available from NIST (fish oil, mussel tissue, whale blubber, and a second fresh frozen fish tissue homogenate prepared from filleted adult lake trout collected from Lake Michigan) and from other organizations such as the National Research Council Canada (ground whole carp), the International Atomic Energy Agency (fish homogenate), and the European Commission Joint Research Centre [fish oils (cod and mackerel) and mussel tissue].