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Jorge O. Ona Ruales, Lane C. Sander, Walter Brent Wilson, Stephen Wise
The relationship of reversed-phase liquid chromatography retention on a polymeric C18 stationary phase and the shape of polycyclic aromatic hydrocarbons (PAHs) was investigated for three-ring to seven-ring cata-condensed isomers. We report the first
Walter B. Wilson, Hugh Hayes, Lane C. Sander, Andres D. Campiglia, Stephen A. Wise
Retention indices for 124 polycyclic aromatic hydrocarbons (PAHs) and 62 methyl-substituted (Me-) PAHs were determined using normal-phase liquid chromatography (NPLC) on a aminopropyl (NH2) stationary phase. PAH retention behavior on the NH2 phase is
Karen W. Phinney, Johanna Camara, Susan Tai, Lane C. Sander, Stephen A. Wise, Linde A. De Grande, Linda M. Thienpont, Antonio M. Possolo, Blaza Toman, Christopher T. Sempos, J. M. Betz, Paul M. Coates
Assay variability has been cited as an obstacle to establishing optimal vitamin D exposure. As part of the Vitamin D Standardization Program (VDSP) effort to standardize the measurement of total 25(OH)D, value assignment of total 25(OH)D in 50 single donor
Karen W. Phinney, Susan S. Tai, Mary Bedner, Johanna Camara, Rosalind R. Chia, Lane C. Sander, Katherine E. Sharpless, Stephen A. Wise, James H. Yen, Rosemary L. Schleicher, Madhulika Chaudhary-Webb, Khin L. Maw, Yasamin Rahmani, Hubert W. Vesper, Joseph M. Betz, Joyce Merkel, Christopher T. Sempos, Paul M. Coates, Ramon Durazo-Arvizu, Kurtis Sarafin, Stephen P. Brooks
Column selection is probably the single most important aspect of method development that will directly affect measurement accuracy and precision of liquid chromatographic (LC) measurements. An understanding of physical and chemical properties of LC columns
The development of fit-for-purpose analytical methods is an essential component of chemical metrology. This presentation will provide guidance on approaches for establishing robust analytical methods, particularly with applications to liquid chromatography
Solid Phase Extraction [video, running time 29 minutes 2 seconds] \\europa\839.02\training\Solid Phase Extraction (29.02 minutes).mp4 Lane C. Sander Chemical Sciences Division Material Measurement Laboratory National Institute of Standards and Technology
The determination of solution density is required for conversion of liquid solution levels from a mass fraction basis to a volume fraction basis. This presentation will provide information about three approaches in common use for the determination of
Chromatography is an example of a process by which a mixture is separated into at least two fractions with different compositions. This presentation will provide a brief overview of the practice of liquid chromatography (LC), with an emphasis on
The setup and maintenance of liquid chromatographic equipment requires a basic knowledge of chromatographic hardware. Tubing connections are an essential component in liquid chromatography instrumentation. System function and performance depend on the
Calibration solutions provide the basis for quantitation for most instrumental techniques. The instrumental responses for analytes in calibrants of known composition are compared with corresponding responses in samples to provide quantitation of the
Pressurized fluid extraction (PFE) is one of several sample preparation methods that can be used to extract targeted analytes from a sample matrix into a solvent, to permit subsequent analysis. With PFE, samples are extracted with solvent in a pressurized
The accurate characterization of the chemical composition of a sample depends on a variety of factors that must be considered by the analyst. Knowledge of how different approaches to quantitation affect the measurement accuracy is requisite to the
Sample Concentration and Processing Sample concentration is a common step in sample preparation prior to analysis that is performed to increase method sensitivity or to exchange solvent environment. Sample concentration can be thought of as a separation
Soxhlet extraction is one of several sample preparation methods that can be used to transfer targeted analytes from a sample matrix into a solvent, to permit subsequent analysis. With Soxhlet extraction, samples are repeatedly extracted with solvent
The ability to assess analytical performance is a fundamental component of measurement science. Ultimately, measurement quality depends on the proper function of instrumentation in combination with appropriate methods. Evidence of proper function is
The determination of mass is a fundamental component in quantitative analysis, and weighing accuracy is an important factor for most applications. This presentation will highlight the use of different types of analytical balances and will demonstrate
Although volumetric measurements are usually less accurate than gravimetric based measurements, volumetric measurements are still in common use due to the convenience, and often higher throughput, that may be afforded by automatic pipettes. Analysts should
Chromatography is an example of a process by which a mixture is separated into at least two fractions with different compositions. Other separation methods exist, such as distillation, recrystallization, and extraction. Chromatography is used to analyze
Walter B. Wilson, Lane C. Sander, Jorge O. Ona Ruales, Stephanie Mossner, Leonard M. Sidisky, Milton Lee, Stephen A. Wise
Retention indices for 10 sets of alkyl-substituted polycyclic aromatic sulfur heterocycles (PASHs) isomers (total of 80 PASHs) were determined using gas chromatography with three different stationary phases: a 50% phenyl phase, a 50% liquid crystalline
Walter B. Wilson, Lane C. Sander, Jorge O. Ona Ruales, Leonard M. Sidisky, Milton Lee, Stephen A. Wise
Retention indices for 70 polycyclic aromatic sulfur heterocycles (PASHs) were determined using gas chromatography with three different stationary phases: a 50% phenyl phase, a 50% liquid crystalline dimethylpolysiloxane (LC-DMPS) phase, and an ionic liquid
Jeanita Pritchett, Katrice A. Lippa, Mary Bedner, Carolyn Q. Burdette, Johanna Camara, Brian E. Lang, Michael A. Nelson, Lane C. Sander, Lorna T. Sniegoski
The one week NIST-SIM chemical metrology training opportunity was designed to provide SIM NMI/DI laboratory personnel with in-depth classroom and hands-on laboratory experience for the implementation of isotope dilution/mass spectrometry (ID/MS) methods in
Melissa M. Phillips, Mary Bedner, Manuela Reitz, Carolyn Q. Burdette, Michael A. Nelson, James H. Yen, Lane C. Sander, Catherine A. Rimmer
Two independent analytical approaches, based on liquid chromatography with absorbance detection and liquid chromatography with mass spectrometric detection, have been developed for determination of isoflavones in soy materials. These two methods yield
Jorge O. Ona Ruales, Walter B. Wilson, Federica Nalin, Lane C. Sander, Patricia Schubert, Stephen A. Wise
A link between the aromatic character of polycyclic aromatic hydrocarbons (PAHs) and gas chromatography (GC) elution order in columns with a polysiloxane backbone in the stationary phase is reported for the first time. The aromatic character was calculated
Walter B. Wilson, Lane C. Sander, M. J. Lopez de Alda, Milton Lee, Stephen A. Wise
Retention indices for 79 alkyl-substituted polycyclic aromatic sulfur heterocycles (PASHs) were determined by using reversed-phase liquid chromatography (LC) on a monomeric and polymeric octadecylsilane (C18) stationary phase. Molecular shape parameters