Carbon stable isotope composition of modern and archaeological Cornelian cherry fruit stones: a pilot study

The carbon stable isotope content of Cornelian cherry stones collected from wild tree stands in Serbia, SE Europe, was measured using elemental analyser-isotope ratio mass spectrometry, with the aim of recording natural carbon isotope composition of the fruit stones and its possible variation. The results show a significant variation in the carbon isotope values; we identified several environmental factors that, along with a number of other possible determinants, likely contributed to this variation. The obtained data are compared with the measurement of carbon isotope content of an archaeological specimen of Cornelian cherry stone discovered at the Neolithic site of Vin?a (ca. 5600–4500 BC) in Serbia. Notwithstanding the limitedness of the data and the complexity surrounding carbon fractionation and the isotopic variation, it is suggested that the differences/similarities in carbon isotope ratios between modern and archaeological Cornelian cherry stones, when measured for much larger assemblages, could potentially offer a glimpse into growing conditions of Cornelian cherry trees in the past.     

Two polydimethylsiloxane rod extraction methods for the sensitive determination of phenolic compounds in water samples

Simple, precise, and low‐cost methods for the simultaneous determination of phenolic endocrine disrupting compounds such as bisphenol A, trichlorophenol, pentachlorophenol, 4‐nonylphenol, and 4‐octylphenol in water samples were developed. The Direct, in situ derivatization methods are based on polydimethylsiloxane rod extraction followed by liquid desorption and chromatographic analysis by liquid chromatography and diode array detection. Several parameters affecting the extraction and desorption of the phenolic compounds and their acetylated derivates were studied, as well as the chromatographic and detection conditions. For the direct method, determination coefficients (r²) > 0.990 and LODs in the 0.6–2 μg/L range were obtained for all compounds except bisphenol A (9.5 μg/L). With the derivatization‐based method, based on in situ acetylation, lower limits of detection (0.3–0.9 μg/L) were obtained for all the compounds with r² > 0.988 and RSDs in the 2–9% range. The developed methods were applied to the analysis of spiked water samples obtaining recoveries of between 60.2 and 131.7% for the direct method, and of between 76.6 and 108.2% for the derivatization‐based method. The results demonstrate the feasibility of using these two methods for determining bisphenol A, trichlorophenol, pentachlorophenol, 4‐nonylphenol, and 4‐octylphenol in water.     

Comparison of two extraction methods for the determination of selective serotonin reuptake inhibitors in sewage sludge by hollow fiber liquid-phase microextraction

This paper presents two procedures for the determination of four selective serotonin reuptake inhibitors (citalopram, paroxetine, fluoxetine, and sertraline) and one metabolite (norfluoxetine) in sewage sludge utilizing three-phase hollow fiber liquid-phase microextraction (HF-LPME). First, direct HF-LPME was used for extraction, clean-up, and preconcentration. The pharmaceuticals were extracted from slurry samples into an organic phase and then back-extracted into an aqueous phase in the lumen of the hollow fiber. Second, a procedure combining pressurized hot water extraction and HF-LPME for clean-up and preconcentration was developed for the same analytes and matrix. The extracts were subsequently analyzed by liquid chromatography-mass spectrometry. For direct HF-LPME, limits of detection were between 1 and 12 ng g(-1) (dry weight) and the relative standard deviation (RSD) values were 3-12%. For the second method, limits of detection were approximately 6 ng g(-1) for all the compounds and RSD values were 8-12%. The methods were validated by comparison of results for the same samples. Sewage sludge from a Swedish wastewater treatment plant was analyzed by both methods; average concentrations were similar for citalopram, paroxetine, and fluoxetine with values of approximately 530, 40, and 200 ng g(-1) , respectively.