Bioaccumulation And Biotransformation of BDE-47 Using Zebrafish Eleutheroembryos (Danio Rerio)

Polybrominated diphenyl ethers (PBDEs) industrially used as flame retardants are nowadays considered emerging pollutants as they are endocrine disrupting chemicals (EDCs), persistent in the environment, bioaccumulative and in addition, its hydroxylated (OH-BDEs) and methoxylated (MeO-BDEs) metabolites have similar ecotoxic properties. The aim of this work was to develop an analytical method to be applied in the study of the bioconcentration and biotransformation of BDE-47 due to its bioavailability, toxicity and high persistence and abundance in environmental samples, including humans. So, a dependable ultrasonic extraction process followed to dispersive SPE clean-up step and GC-MS-μECD detection has worked out for the determination of BDE-47 and its main biotransformation products (MeO-BDEs and OH-BDEs), considering the polarity difference. In addition, an alternative method to bioconcentration official guideline OECD 305, developed previously with zebrafish (Danio rerio) eleutheroembryos (i.e., hatched but not yet free feeding embryos) is used, reducing dramatically the animal suffering but also time and reagents. Bioconcentration factors (BCF) were calculated using first order one-compartment toxicokinetic model. The profiles found show rapid absorption in the first hours of larval development and great bioaccumulative with capacity, finding bioconcentration factors (BCF) of 6631 and 44210 at nominal concentrations of 10 and 1 μg·L-1 (< 1% LC50), respectively. Metabolization studies show increasing concentrations of the metabolites BDE-28, 2'-OH-BDE-28 and 5-MeO-BDE-47 throughout the exposure time. The results obtained show the feasibility of the method for bioaccumulation and opens the possibility of metabolic studies with zebrafish eleutheroembryos, which is a very underdeveloped field without official testing or regulation.

Development of a method for assessing the accumulation and metabolization of antidepressant drugs in zebrafish (Danio rerio) eleutheroembryos

Antidepressant drugs are widely used for the treatment of common mental or other psychiatric disorders such as depression, which affect about 121 million people worldwide. This widespread use has contributed to the input of these pharmaceuticals and their metabolites into the environment. The aim of this work was to develop an analytical method to quantify the most widely used antidepressant drugs, selective serotonin reuptake inhibitors (SSRI), and their main metabolites in the environment. For this, a new and reliable miniaturized extraction method based on dispersive SPE cleanup procedure for extraction of SSRI followed by derivatization with n-heptafluorobutyrylimidazole, and detection by GC-MS was developed. The methodology, including a first-order one-compartment model, was then applied to a bioconcentration study in zebrafish (Danio rerio) eleutheroembryos. The results showed low bioaccumulation of these compounds; however, a biotransformation evidence of the parent compounds into their metabolites was observed after 6 h of exposure. These results indicate the need to integrate metabolic transformation rates to fully model and understand the bioaccumulation patterns of SSRI and their metabolites.

Development of an analytical method for pesticide residues in berries with dispersive solid phase extraction using multiwalled carbon nanotubes and primary secondary amine sorbents

A dispersive SPE with PSA and MWCNTs as sorbent material was developed for pesticide residue analysis in berry samples.

Multiresidue Method for Targeted Screening of Pesticide Residues in Spice Cardamom (Elettaria cardamomum) by Liquid Chromatography with Tandem Mass Spectrometry

A QuEChERS technique–based sample preparation method was optimized and validated in small cardamom to monitor the residues of 154 pesticides by LC with tandem MS. The proposed multiresidue method involved soaking powdered cardamom (2 g) in water (8 mL) for 30 min, followed by extraction with acetonitrile (10 mL). Cleanup by dispersive SPE was performed using primary secondary amine (25 mg/mL), C18 (25 mg/mL), and anhydrous magnesium sulfate (150 mg/mL). The method was validated as per the SANTE/11945/2015 guidelines at 5, 10, 50, and 100 ng/g spiking levels, and most of the analytes showed recoveries between 70 and 120% (with RSDs ≤20%). The LOQ of ≤10 ng/g was achieved for almost 90% of the target pesticides. The measurement uncertainties were evaluated at 100 ng/g, and the global uncertainty values were below 22% for all the analytes.