The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health (NIH), has developed a Standard Reference Material (SRM) to support technology development in metabolomics research. SRM 1950 Metabolites in Human Plasma is intended to have metabolite concentrations that are representative of those found in adult human plasma. The plasma used in the preparation of SRM 1950 was collected from both male and female donors, and donor ethnicity targets were selected based upon the ethnic makeup of the U.S. population. Metabolomics research is diverse in terms of both instrumentation and scientific goals. This SRM was designed to apply broadly to the field, not toward specific applications. Therefore, concentrations of approximately 100 analytes, including amino acids, fatty acids, trace elements, vitamins, hormones, selenoproteins, clinical markers, and perfluorinated compounds (PFCs), were determined. Value assignment measurements were performed by NIST and the Centers for Disease Control and Prevention (CDC). SRM 1950 is the first reference material developed specifically for metabolomics research.

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The solubility of water in octan-1-ol was measured from 275.15 K to 369.15 K by coulometric Karl Fischer titration. The mass fraction solubility, s c, at 298.15 K was found to be (48.91 ± 0.13) mg·g–1. Experiments indicated the existence of a pseudoequilibrium state when there was a significant difference in the temperature of the liquid and the headspace gas. The density of water-saturated octanol (WSO) was measured from 288.15 K to 318.15 K. The density at 298.15 K was determined to be (831.7 ± 1.7) kg·m–3 with a change in density of −0.6 kg·m–3·K–1.

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a b s t r a c tThe thermochemistry of samples of amorphous cellulose, cellulose I, cellulose II, and cellulose III was studied by using oxygen bomb calorimetry, solution calorimetry in which the solvent was cadoxen (a cadmium ethylenediamine solvent), and with a Physical Property Measurement System (PPMS) in zero magnetic field to measure standard massic heat capacities C p;w over the temperature range T = (2 to 302) K. The samples used in this study were prepared so as to have different values of crystallinity indexes CI and were characterized by X-ray diffraction, by Karl Fischer moisture determination, and by using gel permeation chromatography to determine the weight average degree of polymerization DP w . NMR measurements on solutions containing the samples dissolved in cadoxen were also performed in an attempt to resolve the issue of the equivalency or non-equivalency of the nuclei in the different forms of cellulose that were dissolved in cadoxen. While large differences in the NMR spectra for the various cellulose samples in cadoxen were not observed, one cannot be absolutely certain that these cellulose samples are chemically equivalent in cadoxen. Equations were derived which allow one to adjust measured property values of cellulose samples having a mass fraction of water w H 2 O to a reference value of the mass fraction of water w ref . The measured thermodynamic properties (standard massic enthalpy of combustion D c H w , standard massic enthalpy of solution D sol H w , and C p;w ) were used in conjunction with the measured CI values to calculate values of the changes in the standard massic enthalpies of reactionD r H Ã w , the standard massic entropies of reaction D r S Ã w , the standard massic Gibbs free energies of reaction D r G Ã w , and the standard massic heat capacity D r C p;w , for the interconversion reactions of the pure (CI = 100) cellulose allomorphs, i.e., cellulose(am), cellulose I(cr), cellulose II(cr), and cellulose II(cr), at the temperature T = 298.15 K, the pressure p = 0.1 MPa, and w H 2 O = 0.073. The '' ⁄ '' denotes that the thermodynamic property pertains to pure cellulose allomorphs. Values of standard massic enthalpy differences D T 0 H w , standard massic entropy differences D T 0 S w , and the standard massic thermal functionwere calculated from the measured heat capacities for the cellulose samples and for the pure cellulose allomorphs. The extensive literature pertinent to the thermodynamic properties of cellulose has been summarized and, in many cases, property values have been calculated or recalculated from previously reported data. The thermodynamic property data show that cellulose(am) is the least stable of the cellulose allomorphs considered in this study. However, due to the uncertainties in the measured property values, it is not possible to use these values to order the relative stabilities of the cellulose (I, II, and III) crystalline allomorphs with a reasonable degree of certainty. Nevertheless, http://dx.

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A material containing single-wall carbon nanotubes (SWCNTs) with other carbon species, catalyst residues, and trace element contaminants has been prepared by the National Institute of Standards and Technology for characterization and distribution as Standard Reference Material SRM 2483 Carbon Nanotube Soot. Neutron activation analysis (NAA) and inductively coupled plasma mass spectrometry (ICP-MS) were selected to characterize the elemental composition. Catalyst residues at percentage mass fraction level were determined with independent NAA procedures and a number of trace elements, including selected rare earth elements, were determined with NAA and ICP-MS procedures. The results of the investigated materials agreed well among the NAA and ICP-MS procedures and good agreement of measured values with certified values was found in selected SRMs included in the analyses. Based on this work mass fraction values for catalyst and trace elements were assigned to the candidate SRM.