We present two new methods for purifying dinosterol (4a,23,24-trimethyl-5a-cholest-22E-en-3b-ol) from sediments for the purpose of hydrogen isotope analysis via gas chromatography–isotope ratio mass spectrometry (GC–IRMS). The first method uses reversed phase-high performance liquid chromatography (RP-HPLC) to purify dinosterol from structurally similar 4a-methyl sterols that co-elute on GC ana...

In knowledge Economy Times, it’s necessary for knowledge alliance Enterprise (KAE) to build up efficient, reliable information resources management system (IRMS) to make use of the information resources (IR) more availably. This article starts from the characteristics of enterprise information resources (EIR) based on knowledge alliance, analyzing the requirements of establishing IRMS, designin...

RATIONALE Steroids are potent hormones that are found in many environments. Yet, contributions from synthetic and endogenous sources are largely uncharacterized. The goal of this study was to evaluate whether carbon isotopes could be used to distinguish between synthetic and endogenous steroids in wastewater and other environmental matrices. METHODS Estrogens and progestogens were isolated fr...

Paleoenvironmental information is better preserved in carbonate concretions. In this study, concretions the Cretaceous Nenjiang shale, Songliao Basin, were examined to determine whether molecular fossils reflective of paleoenvironment at these sites. Organic and inorganic geochemical characteristics surrounding rocks analyzed using a series techniques, including SEM, LA-ICP-MS, GC-MS-MS, GC-IRM...

In spite of extensive efforts, even the most experienced laboratories dealing with isotopic measurements of atmospheric CO2 still suffer from poor inter-laboratory consistency. One of the complicating factors of these isotope measurements is the presence of N2O, giving rise to mass overlap in the isotope ratio mass spectrometer (IRMS). The aim of the experiment reported here has been twofold: f...

RATIONALE Liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) is currently the most accurate and precise technique for the measurement of compound-specific stable carbon isotope ratios ((13)C/(12)C) in biological metabolites, at their natural abundance. However, until now this technique could not be applied for the analysis of nucleic acids, the building blocks of the carriers of ge...

There is a growing need for novel vaccine adjuvants that can provide safe and potent T-helper type 1 (Th1) activity. RNA-like immune response modifiers (IRMs) are candidate T-cell adjuvants that skew acquired immune responses towards a Th1 phenotype. We set out to delineate the essential signaling pathways by which the RNA-like IRMs, resiquimod (R-848) and polyinosinic:polycytidylic acid (poly ...

With the difference in photosynthesis process between C3- and C4-plants, 13C/12C stable isotope ratio of ethanol, i.e., δ13C-ethanol, can potentially be a basis for discrimination Scotch whiskies derived from different raw materials. This study analyzed 51 authentic single malt 34 blended by gas chromatography–combustion–isotope mass spectrometry (GC-C-IRMS) examined resulting data series fitti...

Architectural paints are commonly found as trace evidence at scenes of crime. Currently the most widely used technique for the analysis of architectural paints is Fourier Transformed Infra-Red Spectroscopy (FTIR). There are, however, limitations to the forensic analysis of white paints, and the ability to discriminate between samples. Isotope ratio mass spectrometry (IRMS) has been investigated...