Benzo(b)fluoranthene and benzo(k)fluoranthene removal by microalgae in the presence of triazine herbicides: Matrix solid-phase dispersion and solid-phase extraction (MSPD/SPE) for HPLC-UV analysis of the different culture components.

Over the last decade, human activities in the industrial and agricultural sectors have significantly increased the concentration of persistent and harmful pollutants in aquatic ecosystems. The use of microorganisms is a green strategy for the bio-removal of certain contaminants. However, other pollutants in the same ecosystems can reduce their degrading activity and even affect their survival.

Benzo(k)fluoranthene and benzo(b)fluoranthene degradation by Selenastrum capricornutum and identification of metabolites using HPLC-FD and HPLC-ESI-QqQ-MS/MS.

Selenastrum capricornutum efficiently degrades high molecular weight polycyclic aromatic hydrocarbons (HMW PAHs). Until now, there are few studies on the benzo(k)fluoranthene (BkF) and benzo(b)fluoranthene (BbF) biodegradation by this microalga. For this reason, in the present work, extracts obtained from cultures of S.

Electrophoretic characterization of cellular and extracellular proteins from Selenastrum capricornutum cultures degrading benzo(a)pyrene and their identification by UPLC-ESI-TOF mass spectrometry.

Selenastrum capricornutum efficiently degrades benzo(a)pyrene (BaP) but few proteins related to BaP degradation have been identified in this microalgae. So far, it has only been suggested that it could degrade BaP via the monooxygenase and/or dioxygenase pathways. To know more about this fact, in this work, cultures of S.

Semi-continuous monitoring of HMWPAH in microalgae cultures by PT-SPE/HPLC/FD-UV: Estimation of the degradation constant.

A degradation study has been performed with Selenastrum capricornutum incubated with benzo[a]anthracene and benzo[a]pyrene at 50, 100 and 266 ng mL in liquid cultures. After incubation, these high molecular weight polycyclic aromatic hydrocarbons (HMW PAH) were extracted from both, the medium and biomass in a single step, and then quantified by a sensitive and validated analytical methodology based on pipette-tip SPE and HPLC with fluorescence and UV detection (PT-SPE/HPLC/FD-UV). The methodology presented good linearity r > 0.

A review on the enzymes and metabolites identified by mass spectrometry from bacteria and microalgae involved in the degradation of high molecular weight PAHs.

High molecular weight PAHs (HMW PAHs) are dangerous pollutants widely distributed in the environment. The use of microorganisms represents an important tool for HMW PAHs bioremediation, so, the understanding of their biochemical pathways facilitates the development of biodegradation strategies. For this reason, the potential role of species of microalgae, bacteria, and microalga-bacteria consortia in the degradation of HMW PAHs is discussed.

On-line SPE chromatography with spectrophotometric diode array detection as a simple and advantageous choice for the selective trace analysis of benzo(a)anthracene degradation products from microalgae.

In this work, a methodology based on on-line solid phase extraction (SPE) chromatography with spectrophotometric diode array detection was optimized and validated for the trace analysis of benzo(a)anthracene dihydrodiol degradation products from microalgae cultures 5,6-dihydrodiol, 8,9-dihydrodiol and 10,11-dihydrodiol. The two on-line methods for the constituents of the culture, an SPE/on-line SPE chromatographic method for liquid medium and a matrix solid phase dispersion (MSPD)/on-line SPE chromatographic method for biomass presented good linearity in the ranges of 0.5-47ngmL and 2-80ngmg of samples, respectively, with correlation coefficients r>0.

On-line MSPD-SPE-HPLC/FLD analysis of polycyclic aromatic hydrocarbons in bovine tissues.

A fast method was optimized and validated for simultaneous trace determination of four polycyclic aromatic hydrocarbons: benzo[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene in bovine tissues. The determination was performed by matrix solid-phase dispersion (MSPD) coupled on-line to solid phase extraction (SPE) and high performance liquid chromatography (HPLC) with fluorescence detection (FLD). The sample was dispersed on C silica sorbent and then the on-line MSPD-SPE-HPLC/FLD method was applied.

Monitoring dihydrodiol polyaromatic hydrocarbon metabolites produced by the freshwater microalgae Selenastrum capricornutum.

We found that microalgae exposed to a mixture of polycyclic aromatic hydrocarbons (PAHs) did not show growth inhibition. Thus, we assumed that they could metabolize these compounds. In this study, the dihydrodiol-type PAH metabolites of benzo(a)pyrene (BaP), benzo(a)anthracene (BaA), benzo(b)fluoranthene (BbF) and benzo(k)fluoranthene (BkF) produced by the freshwater microalgae Selenastrum capricornutum were monitored and quantified using high-performance liquid chromatography with fluorescence detection (HPLC-FD) techniques.

Biodegradation of benzo(a)pyrene by two freshwater microalgae Selenastrum capricornutum and Scenedesmus acutus: a comparative study useful for bioremediation.

A comparative evaluation of the removal of benzo(a)pyrene (BaP) by sorption and degradation by two microalgal species, Selenastrum capricornutum and Scenedesmus acutus was performed. The monitoring of the amount of BaP remaining in the liquid culture media and the biomass along with the appearance of three metabolites (4,5 dihydrodiol-BaP; 7,8-dihydrodiol-BaP; and 9,10 dihydrodiol-BaP) at short time periods (from 0.25 to 72 h) in cultures exposed to BaP was made by high-performance liquid chromatography (HPLC) with fluorescence and UV detection.

Extraction and analysis of polycyclic aromatic hydrocarbons and benzo[a]pyrene metabolites in microalgae cultures by off-line/on-line methodology based on matrix solid-phase dispersion, solid-phase extraction and high-performance liquid chromatography.

This paper describes the development and validation of an analytical methodology to determine the presence of four PAHs: benzo[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene and benzo[a]pyrene in cultures of the green microalgae Selenastrum capricornutum. The metabolites of benzo[a]pyrene (BaP), 4,5-dihydrodiol benzo[a]pyrene, 9,10-dihydrodiol benzo[a]pyrene, 3-hydroxy benzo[a]pyrene and 9-hydroxy benzo[a]pyrene were also included. The methodology consisted of three parts: (1) separation of liquid media from biomass samples by centrifugation of pure cultures, (2) off-line extraction of analytes from biomass by a miniaturized matrix solid phase dispersion (MSPD) method and from liquid media by a solid phase extraction (SPE) method and (3) on-line SPE preconcentration and analysis of the MSPD and SPE extracts, separately, by high performance liquid chromatography with fluorescence detection (HPLC-FD).

Determination of organophosphorus pesticides in bovine tissue by an on-line coupled matrix solid-phase dispersion-solid phase extraction-high performance liquid chromatography with diode array detection method.

A miniaturized method based on matrix solid-phase dispersion coupled to solid phase extraction and high performance liquid chromatography with diode array detection (MSPD-SPE-HPLC/DAD) was developed for the trace simultaneous determination of the following organophosphorus pesticides (OPPs) in bovine tissue: parathion-methyl, fenitrothion, parathion, chlorfenvinphos, diazinon, ethion, fenchlorphos, chlorpyrifos and carbophenothion. To perform the coupling between MSPD and SPE, 0.05 g of sample was dispersed with 0.

Speciation and transformation pathways of chlorophenols formed from chlorination of phenol at trace level concentration.

Trace organic precursors remaining in water after primary treatment can originate a variety of toxic disinfection by-products during chlorination. Therefore, knowledge of conditions leading to their persistence or transformation in chlorinated media is crucial for human health protection. Using phenol as model compound at trace level (50 ppb), the short term formation and degradation of chlorophenols (CPs) in plain water and buffered water (pH 4.

A method for the analysis of organophosphorus pesticide residues in Mexican axolotl.

A method based on matrix solid-phase dispersion (MSPD) was developed for quantitative extraction of three organophosphorus pesticides (OPPs) from the Mexican axolotl, Ambystoma mexicanum. The determination was carried out using high- performance liquid chromatography (HPLC) with diode array spectrophotometric UV detection (DAD). The MSPD extraction with octadecylsilyl (C18) sorbent combined with a silica gel clean-up and acetonitrile elution was optimised for chlorpyrifos, fenthion and methyl parathion.

Binding characteristics of bovine serum albumin encapsulated in sol-gel glasses: an alternative for protein interaction studies.

Silica glasses doped with 500-700 microg of bovine serum albumin were prepared by the sol-gel method; two pH conditions (pH 5 and 7) were assayed for protein encapsulation. Both biomaterials showed a highly porous structure, with pore sizes in the range 5-28 nm. Columns packed with the ground biogels were on-line coupled to a C18 HPLC column for evaluation of the entrapped protein binding properties using propranolol.

Relative influence of the dissolved humic material on the solid-phase extraction efficiency of pesticides from environmental water.

The effect of organic matter on the solid-phase extraction (SPE) efficiency for pesticides belonging to different chemical groups (urea-derivatives, carbamates and triazines) and having different polarities, was simultaneously studied for the first time in pure and simulated water samples. SPE was carried out in precolumns packed with C18 silica or styrene-divinylbenzene copolymer PLRP-S phases on-line coupled to high performance liquid chromatography (HPLC) analysis. Retention factors in water (k'(W)) were estimated for 25 compounds and used for the calculation of the theoretical breakthrough volume (Vb(T)) in pure water.

Sol-gel immunosorbents doped with polyclonal antibodies for the selective extraction of malathion and triazines from aqueous samples.

Sol-gel immunosorbents (IS) prepared by encapsulation of polyclonal antibodies in silica were packed in cartridges and evaluated for selective immunoaffinity extraction (IAE) of malathion and triazines from aqueous samples. Encapsulated atrazine antibodies highly cross-reacted with simazine and propazine but did not recognize prometon and prometryn. No cross-reactivity of malathion antibodies was observed with the closely related metabolites oxomalathion and isomalathion.