Glucose Sensing by Time-Resolved Fluorescence of Sol-Gel Immobilized Glucose Oxidase

A monolithic silica gel matrix with entrapped glucose oxidase (GOD) was constructed as a bioactive element in an optical biosensor for glucose determination. Intrinsic fluorescence of free and immobilised GOD was investigated in the visible range in presence of different glucose concentrations by time-resolved spectroscopy with time-correlated single-photon counting detector. A three-exponential model was used for analysing the fluorescence transients. Fractional intensities and mean lifetime were shown to be sensitive to the enzymatic reaction and were used for obtaining calibration curve for glucose concentration determination. The sensing system proposed achieved high resolution (up to 0.17 mM) glucose determination with a detection range from 0.4 mM to 5 mM

Endocrine Disruptors: Hidden killers in our food.A review on some Italian products (Chapter 8)

This book provided experimental evidence supporting the fact that some synthetic chemicals were able to interfere with the hormonal messages involved in the growth and development of living organisms, starting from the fetus. Endocrine Disruptors (EDs) are a heterogeneous class of chemicals encompassing persistent contaminants (dioxins, polychlorinated, biphenyls, flame retardants), pesticides (triazoles, triazines, organic chlorinated or phosphoric compounds), substances from the industrial world (phthalates, bisphenols), and synthetic drugs (diethylstilbestrol or 17-alfa ethinylestradiol). EDCs interact with germ cells by altering the epigenoma. Human exposure to EDCs cover the entire life: from the gestation to the dead. The main route of EDCs assumption by living organisms is food.More studied EDCs are phenol compounds such as bisphenols and plasticizers such as phthalates, pesticides and dioxins. In chapter 8 EDCs presence in some food of major consumption , such as milk, fresh or canned fish, canned tomatoes, beverages and soft drinks of Italian market was considered

Simultaneous determination of fifteen multiclass organic pollutants in human saliva and serum by liquid chromatography–tandem ultraviolet/fluorescence detection: A validated method

A quick and inexpensive validated method, based on sample treatment by liquid–liquid microextraction followed by liquid chromatography (LC) coupled with ultraviolet tandem fluorescence detection is proposed for the determination of 15 multiclass pollutants both in serum and in saliva, as a simple and easy to draw matrix. The method was set up and validated according to European guidelines. The compounds of interest include some endocrine‐disrupting chemicals (i.e. bisphenol A, bisphenol B, bisphenol E, bisphenol F, bisphenol AF, bisphenol A diglycidyl ether, bisphenol M, diethylhexyl phthalate, monoethylhexyl phthalate, triclosan and 4‐nonylphenol), as well as other pollutants belonging to the class of volatile organic compounds (2‐chlorophenol, 1,2 dichlorobenzene, 1,2,4,5‐tetrachlorobenzene). The limits of quantifications ranged from 2.28 × 10−3 μg mL−1 (bisphenol A diglycidyl ether) to 6.29 μg mL−1 (diethylhexyl phthalate), while those of detection ranged from 0.068 × 10−3 μg mL−1 (bisphenol A diglycidyl ether) to 1.031 μg mL−1 (diethylhexyl phthalate). To test method suitability, it was applied to real saliva and serum samples of healthy human volunteers and was found to meet the demands of the laboratories handling simple and relatively inexpensive equipment for screening oriented at rapid and reliable contamination assessment of a population

Occurrence of Bisphenol A and its analogues in some foodstuff marketed in Europe

Bisphenol A and its analogues belong to the class of endocrine disrupting chemicals, massively employed by industries to produce polycarbonate and epoxy resins, designed to be in direct contact with foodstuffs. Their leaching from the canned packaging into its content results in food contamination. This review aims at offering a country-specific overview of the occurrence of bisphenols in six main categories of foodstuff marketed in the EU, based on monitoring studies performed in the 27 EU countries for which data are available and prevalently published in the last five years.The general overview of the literature data shows that concentration values of BPs detected into foodstuff is lower in Northern Europe than Southern Europe. A probable daily intake was hypothesized for some countries to provide an EU population exposure assessment. The consumption of canned meat and vegetables is responsible of PDI values higher than those of other food categories. These data emphasize that food and beverage monitoring should deserve greater attention especially by European countries for which no studies are available and especially with regards to bisphenols other than BPA whose limits are not set by the European regulations and whose toxicity has not been fully established

Bisphenol A removal by a Pseudomonas aeruginosa immobilized on granular activated carbon and operating in a fluidized bed reactor

Serratia rubidiae, Pseudomonas aeruginosa and Escherichia coli K12 have been studied for their ability ofBisphenol A removal from aqueous systems and biofilm formation on activated granule carbon. Math-ematical equations for biodegradation process have been elaborated and discussed. P. aeruginosa wasfound the best strain to be employed in the process of Bisphenol A removal. The yield in BPA removalof a P. aeruginosa biofilm grown on GAC and operating in a fluidized bed reactor has been evaluated.The results confirm the usefulness in using biological activated carbon (BAC process) to remove phenolcompounds from aqueous systems

S2O8(2-)/UV-C and H2O2/UV-C treatment of Bisphenol A: Assessment of toxicity, estrogenic activity, degradation products and results in real water

The performance of S2O8 2/UV-C and H2O2/UV-C treatments was investigated for the degradation and detoxification of Bisphenol A (BPA). The acute toxicity of BPA and its degradation products was examined with the Vibrio fischeri bioassay, whereas changes in estrogenic activity were followed with the Yeast Estrogen Screen (YES) assay. LC and LC–MS/MS analyses were conducted to determine degradation products evolving during photochemical treatment. In addition, BPA-spiked real freshwater samples were also subjected to S2O82/UV-C and H2O2/UV-C treatment to study the effect of a real water matrix on BPA removal and detoxification rates. BPA removal in pure water was very fast (67 min) and complete via both H2O2/UV-C and S2O82/UV-C treatment, accompanied with rapid and significant mineralization rates ranging between 70% and 85%. V. fischeri bioassay results indicated that degradation products being more toxic than BPA were formed at the initial stages of H2O2/UV-C whereas a rapid and steady reduction in toxicity was observed during S2O82/UV-C treatment in pure water. UV-C treatment products exhibited a higher estrogenic activity than the original BPA solution while the estrogenicity of BPA was completely removed during H2O2/UV-C and S2O82/UV-C treatments parallel to its degradation. 3-methylbenzoic and 4-sulfobenzoic acids, as well as the ring opening products fumaric, succinic and oxalic acids could be identified as degradation products. BPA degradation required extended treatment periods (>20 min) and TOC removals were considerably retarded (by 40%) in the raw freshwater matrix most probably due to its natural organic matter content (TOC = 5.1 mg L1). H2O2/UV-C and S2O82/UV-C treatment in raw freshwater did not result in toxic degradation products