Application of SPME to the determination of alkylphenols and bisphenol A in cyanobacteria culture media

Smelling the difference: separation of healthy and infected button mushrooms via microbial volatile organic compounds

In the literature there is a lack of consensus regarding mushroom volatiles; most of the studies identify only a few volatiles. This study deals with button mushrooms, their emitted volatiles, and the main changes during infections (green mould and cobweb disease) in a time series experiment. Emitted volatile profiles were determined using HS-SPME-GC-MS coupled analytical technique. The separation of healthy and infected mushroom samples was done using different multivariate statistical methods (PCA, PLS-DA, HeatMap). The main volatile compounds were also determined. As a result, several compounds were found to successfully distinguish healthy (bisabolene, cymene, myrtenol, d-limonene, etc.) and infected (thujopsene, cedr-8-ene, chamigrene, patchulane, longifolene, etc.), mushroom samples, and an early disease detection was achieved. Results can be used for further investigation of infected mushroom identification in an early stage in packaged mushroom products. Furthermore, these results could help to identify infections in commercially available mushrooms, thus increasing shelf-life in super/hypermarkets.

Simultaneous determination of 9 environmental pollutants including bisphenol A in vegetable oil by solid phase extraction-liquid chromatography-tandem mass spectrometry

In this study, a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method with solid phase extraction was established for the simultaneous determination of bisphenol A, bisphenol F, bisphenol S, 4-nonylphenol, n-nonylphenol, octylphenol, n-octylphenol, perfluorooctane sulfonate acid and perfluorooctanoic acid in vegetable oil. The sample was extracted with ammonia acetonitrile solution (1 : 9, V/V) by ultrasonication. And the obtained extract was purified by using a PRIME HLB solid phase extraction column. The identification and quantification of the compounds was performed by liquid chromatography-tandem mass spectrometry in multiple reaction monitoring (MRM) mode. The internal standard method was used for quantitative analysis. Under optimal experimental conditions, the limits of quantitation of bisphenol A, bisphenol F, bisphenol S, 4-nonylphenol, n-nonylphenol, octylphenol and n-octylphenol in vegetable oil were 1.0 μg kg-1. The limits of quantitation of perfluorooctane sulfonic acid and perfluorooctanoic acid in vegetable oil were 0.1 μg kg-1. The average spiked recoveries of the method were in the range of 89.2-117.1% with the relative standard deviations (RSD) of 2.9-9.8% (n = 6). This method is sensitive, versatile and reproducible, and is suitable for the simultaneous determination of bisphenol A, bisphenol F, bisphenol S, 4-nonylphenol, n-nonylphenol, octylphenol, n-octylphenol, perfluorooctane sulfonate acid and perfluorooctanoic acid in vegetable oil.

Fate and effects of octylphenol in a Microcystis aeruginosa culture medium

Octylphenol (OP) is a xenobiotic with endocrine disrupting properties found in freshwaters worldwide. Its effects have been studied in organisms with nuclear receptors but effects on phytoplankton communities are poorly characterized, despite the fact that these organisms are constantly exposed to this compound. For this reason fate and effects of OP in the cyanobacterium Microcystis aeruginosa were assessed from 10 nM to 5 microM OP concentration. Up to a test concentration of 250 nM, OP removal increased significantly in the presence of cyanobacteria, the compound half-life in the absence of cells being 15 days against 9 days in the presence of the cells. Only 4% of the total OP removed was found bound to the cells, indicating an active metabolization of the compound. Moreover, the role of the exudates produced by M. aeruginosa, in the OP removal from culture medium, was assessed. Culture medium with exudates, resulting from a 7-day growth of M. aeruginosa, spiked with 50 nM OP, showed a higher half-life (22 days). Compared to culture medium without exudates, it can be hypothesized that higher organic matter concentrations make the hydrolysis or photolysis of OP more difficult. In culture media, the cells of M. aeruginosa could compensate and even counteract this, as OP half-life was shortened. At higher OP levels (1.25 and 5 microM) M. aeruginosa growth was impaired, indicating toxic effects. This shortage of biomass prevented the M. aeruginosa-assisted OP withdrawal from the culture media.

Solid-phase/supercritical-fluid extraction for liquid chromatography of phenolic compounds in freshwater microalgae and selected cyanobacterial species

In the present paper a new extraction technique based on the combination of solid-phase/supercritical-fluid extraction (SPE/SFE) with subsequent reversed-phase HPLC is described. The SPE/SFE extractor was originally constructed from SPE-cartridge incorporated into the SFE extraction cell. Selected groups of benzoic acid derivatives (p-hydroxybenzoic, protocatechuic, gallic, vanillic and syringic acid), hydroxybenzaldehydes (4-hydroxybenzaldehyde and 3,4-dihydroxybenzaldehyde) and cinnamic acid derivatives (o-coumaric, p-coumaric, caffeic, ferulic, sinapic and chlorogenic acid) were extracted. Cyclic addition of binary extraction solvent system based on methanol:water (1:1, v/v) and methanol/ammonia aqueous solution was used for extraction at 40MPa and 80 degrees C. The p-hydroxybenzoic, protocatechuic, vanillic, syringic, caffeic and chlorogenic acid; 4-hydroxybenzaldehyde and 3,4-dihydroxybenzaldehyde were identified by HPLC-electrospray mass spectrometry in SPE/SFE extracts of acid hydrolyzates of microalga (Spongiochloris spongiosa) and cyanobacterial strains (Spirulina platensis, Anabaena doliolum, Nostoc sp., and Cylindrospermum sp.). For the identification and quantification of the compounds the quasi-molecular ions [M-H](-) and specific fragments were analysed by quadrupole mass spectrometry analyzer. Our analysis showed that the microalgae and cyanobacteria usually contained phenolic acids or aldehydes at microg levels per gram of lyophilized sample. The proposed SPE/SFE extraction method would be useful for the analysis of different plant species containing trace amount of polar fraction of phenols.