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Abstract: A new coating material was used for a stir bar sorptive extraction (SBSE) method coupled to a high throughput sample analysis technique. This allowed for a simple procedure for fast determinations of eight steroid hormones (estriol, estradiol, ethynylestradiol, estrone, progesterone, medroxyprogesterone, levonorgestrel, northindrone) in water. Sample pre-treatment was performed using an in-house SBSE method based on a polydimethylsiloxane/phenyltrimethylsiloxane/β-cyclodextrin sol–gel material. The analytes were desorbed by liquid extraction prior to their analysis by laser diode thermal desorption/atmospheric pressure chemical ionization coupled to tandem mass spectrometry (LDTD–APCI–MS/MS). Several parameters, including ionic strength, volume and time of extraction as well as volume and time of desorption, were investigated to maximize extraction efficiency by SBSE in aqueous solutions. The in-house stir bar showed good reproducibility and could be used for at least 50 extractions without affecting analytical performance. The recoveries of the spiked steroid hormones ranged from 55% to 96% in all water matrices studied (HPLC grade water, tap water and raw wastewater). Only one compound showed poor recovery values (<2% for estriol) in all matrices. The method detection limits (MDLs) in real matrices were within the range of 0.1–0.3μgL−1 except for estriol at 48μgL−1. The extraction performance of the in-house SBSE for the eight selected hormones was also compared with that of a commercially-available stir bar coated with polydimethylsiloxane (PDMS). This novel stir bar coating could prove to be useful method for the detection and quantification of trace levels of steroid hormones. [Copyright &y& Elsevier]

Abstract: Plasmodium falciparum is the causative agent of malaria, a deadly infectious disease for which treatments are scarce and drug-resistant parasites are now increasingly found. A comprehensive method of identifying and quantifying metabolites of this intracellular parasite could expand the arsenal of tools to understand its biology, and be used to develop new treatments against the disease. Here, we present two methods based on liquid chromatography tandem mass spectrometry for reliable measurement of water-soluble metabolites involved in phospholipid biosynthesis, as well as several other metabolites that reflect the metabolic status of the parasite including amino acids, carboxylic acids, energy-related carbohydrates, and nucleotides. A total of 35 compounds was quantified. In the first method, polar compounds were retained by hydrophilic interaction chromatography (amino column) and detected in negative mode using succinic acid-13C4 and fluorovaline as internal standards. In the second method, separations were carried out using reverse phase (C18) ion-pair liquid chromatography, with heptafluorobutyric acid as a volatile ion pairing reagent in positive detection mode, using d9-choline and 4-aminobutanol as internal standards. Standard curves were performed in P. falciparum-infected and uninfected red blood cells using standard addition method (r 2 >0.99). The intra- and inter-day accuracy and precision as well as the extraction recovery of each compound were determined. The lower limit of quantitation varied from 50pmol to 100fmol/3×107 cells. These methods were validated and successfully applied to determine intracellular concentrations of metabolites from uninfected host RBCs and isolated Plasmodium parasites. [Copyright &y& Elsevier]

Excess rainfall events could lead to overflows and combined sewer overflows, which could threaten local mussel populations. This study sought to compare the long- term effects of combined sewer overflows and treated municipal effluents in caged Elliptio complanata mussels. Mussels were caged at 2 overflow sites, one downstream site of a major municipal effluent dispersion plume and a reference upstream site for 3 months during the summer. At the end of the exposure period, mussels were collected, analyzed for municipal contaminants (including pharmaceuticals), and effects biomarkers based on endocrine disruption (vitellogenin expression), xenobiotic detoxification (glutathione S-transferase and metallothioneins), oxidative stress/inflammation (cyclooxygenase and lipid peroxidation) and DNA damage. The data revealed that surface waters contained less pharmaceutical products than the downstream site but atrazine and its metabolite were at higher levels in overflow sites. Mussels contained elevated amounts of total heterotrophic bacteria, caffeine, acebutolol and venlafaxine at the downstream site relative to the upstream site where caffeine was higher at one of the overflow site. The levels of vitellogenin gene expression were significantly increased in both sexes of mussels caged at the downstream site only. Multivariate analysis revealed that the biomarker responses were completely separated between upstream, overflow and downstream sites. The site discrimination was based on vitellogenin, metallothioneins, DNA damage in gonad and digestive gland, gonad lipids/proteins reserves, lipid peroxidation, gonado-somatic index and condition factor. Adverse outcome pathways analysis using the power law approach revealed that most changes in the biomarkers identified by discriminant function analysis were significantly scaled to gonad energy reserves, tissue/ mussel size and loss of weight following air emersion stress. In conclusion, the toxic effects of mussels caged at overflow sites generally displayed lower responses than mussels caged downstream a treated municipal effluent suggesting that these overflows pose a lower risk than the continuous exposure to treated municipal effluent. [ABSTRACT FROM AUTHOR]