We present a compilation of tropospheric 14 CO 2 for the period 1950–2010, based on published radiocarbon data from selected records of atmospheric CO 2 sampling and tree-ring series. This compilation is a new version of the compilation by Hua and Barbetti (2004) and consists of yearly summer data sets for zonal, hemispheric, and global levels of atmospheric 14 C. In addition, compiled (and extended) monthly data sets for 5 atmospheric zones (3 in the Northern Hemisphere and 2 in the Southern Hemisphere) are reported. The annual data sets are for use in regional and global carbon model calculations, while the extended monthly data sets serve as calibration curves for 14 C dating of recent, short-lived terrestrial organic materials. DOI:  10.2458/azu_js_rc.v55i2.16177

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Atmospheric Radiocarbon for the Period 1950–2010

With the development of rapid measurement techniques, stable oxygen isotope analysis of plant tissue is poised to become an important tool in plant physiological, ecological, paleoclimatic and forensic studies. Recent advances in mechanistic understanding have led to the improvement of process-based models that accurately predict variability in the oxygen isotope composition of plant organic material (δ18Op). δ18Op has been shown to reflect the isotope composition of soil water, evaporative enrichment in transpiring leaves, and isotopic exchange between oxygen atoms in organic molecules and local water in the cells in which organic molecules are formed. This review presents current theoretical models describing the influences on δ18Op, using recently published experimental work to outline strengths and weaknesses in the models. The potential and realised applications of the technique are described.

Stable oxygen isotope composition of plant tissue: a review

Enantioselective determination by capillary electrophoresis with cyclodextrins as chiral selectors.

https://escholarship.org/content/qt8xh0s7nf/qt8xh0s7nf.pdf?t=oyg19p

Fentanyl, fentanyl analogs and novel synthetic opioids: A comprehensive review

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Fentanyl, fentanyl analogs and novel synthetic opioids: A comprehensive review - eScholarship

Cocaine carries a chemical fingerprint from the region where the coca was grown. Here we show that cocaine originating from different geographic regions in South America can be identified by its isotope-ratio signature. The distinct carbon (δ13C) and nitrogen (δ15N) isotope-ratio combinations allow the country of origin to be determined for the principal coca-growing regions along the Andean Ridge. By combining this information with detectable differences in the patterns of the trace alkaloids truxilline and trimethoxycocaine, we correctly identified the source of 96% of 200 cocaine samples.

Tracing the geographical origin of cocaine.

The signature patterns of cocaine samples were examined by capillary gas chromatography using 14 impurities commonly found in illicit cocaine samples. The procedure is based on acidic, basic, and neutral impurities introduced from the coca plant and from the processing of cocaine in clandestine laboratories. Impurities containing either alcoholic, N-nor, or carboxylic acid functional groups were analyzed as their silyl derivatives. The reported procedure provides a simple one-step assay for obtaining chromatographic impurity signature profile analyses (CISPA) of illicit cocaine samples using flame ionization detection (FID).

John F. Casale

Papers

Tracing the geographical origin of cocaine.

A Chromatographic Impurity Signature Profile Analysis for Cocaine Using Capillary Gas Chromatography

In-depth chromatographic analyses of illicit cocaine and its precursor, coca leaves

Separation and detection of acidic and neutral impurities in illicit heroin via capillary electrophoresis

Determination and in-depth chromatographic analyses of alkaloids in South American and greenhouse-cultivated coca leaves