Influence of Different Redox Conditions on the Biodegradation of the Pesticide Metabolites Phenol and Chlorophenols

Abstract

The fate and behaviour of phenol and monochlorophenols during bankfiltration and underground passage with variable redox conditions were investigated. A model ecosystem was used consisting in laboratory filter columns filled with natural underground material and operated with natural aerobic and anaerobic groundwater to create different redox situations.

The test substances (phenol, 2-chlorophenol, 3-chlorophenol, 4-chlorophenol) were added continuously to the infiltrating water and their concentration in the filter effluents determined. Beside the redox conditions other factors known to affect microbial degradation processes like the substrate concentration and the underground material were varied stepwise.

Phenol was degraded under both, aerobic and anaerobic conditions. The presence of oxygen is more favourable to degradation; no lag phase was observed under aerobic conditions. In a sulfate reducing environment, phenol could only be degraded after microbial adaptation. The length of the lag phase was strongly influenced by the substrate concentration and the undergroundmaterial. Prior contact with phenol resulted in a shorter lag phase.

Monochlorophenols behaved almost persistent in the model system. Degradation could only be observed in a test filter that provided a more active microbial population due to prior adaptation to phenol and a more favourable underground material.     

Anti-steatosis compounds from leaves of Mallotus furetianus

There is no drug administration-approved therapy for non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). In this study, eight compounds, gallic acid (1), methyl gallate (2), corilagin (3), 3,4,8,9,10-pentahydroxydibenzo[b,d]pyran-6-one (4), repandinin B (5), (Z)-3-hexenyl-β-D-glucopyranoside (6), (+)-lyoniresinol-3α-O-α-L-rhamnopyranoside (7) and mallophenol A (8) were isolated from the active fractions of Mallotus furetianus. Three compounds, (6, 7 and 8) revealed potent anti-steatosis activity in the oleic acid (OA)-induced steatosis cell model, with the minimum effective concentration of 0.05 (6), 0.0005 (7) and 0.0005 (8) μg/mL, which were much lower than the control compound, fibrate (72.4 μg/mL).     

Determination of Fumonisin B1 in Corn by High Performance Liquid Chromatography With Fluorescence Detection

Abstract

A method is described for the determination of fumonisin B1 in corn. The method involves sample extraction with methanol:water (75:25) and partial purification using a solid phase extraction. Fumonisin B1 is reacted with naphthalene-2,3-dicarboxaldehyde (NDA) to produce a highly fluorescent derivative, 1-cyano-2-alkyl-benz[f]isoindole (CBI) and then separated from the sample matrix on a reverse phase C-18 column with a mobile phase of acetonitrile:water:acetic acid (55:45:1). The NDA-derivative is quantitated by fluorescence detection at 410 nm excitation and a 440 nm, long past emission filter. Recoveries of fumonisin B1 added to corn at levels of 0.25–20.0 μg/g averaged 88.1% with a coefficient of variation of 10.3%. Confirmation of fumonisin B1 in corn samples was accomplished by fast atom bombardment (FAB) spectroscopy.     

Determination of Iron (II) in Water by a Spectrophotometric Method After Preconcentration on an Organic Solvent-Soluble Membrane Filter

Abstract

A solvent-soluble membrane filter is proposed for a simple and rapid preconcentration and spectrophotometric determination of iron (II), which was collected on a nitrocellulose membrane filter as an ion-associate of the cationic complex of iron (II)-1,10-phenanthroline with an anionic surfactant of dodecyl sulfate. The ion-associate collected was dissolved in 5 ml of 2-methoxyethanol together with the filter. The color intensity due to the ion-associate in the resulting solution was measured at 510 nm against a reagent blank. Beer's law is obeyed in the range 1–15 μg Fe (II) in 5 ml of solvent with excellent reproducibility, and detection limits better than 0.5 μg dm^?3 as Fe (II) can be achieved. The diverse components normally present in water do not interfere when proper masking reagent is added. The proposed method has been applied to the analysis of water samples from several sources such as river water, ground water and tapwater samples, the recoveries of the iron (II) added to the samples are quantitative, and results found are satisfactory.     

A Piezoelectric Sensor for Dissolved Careon Dioxide

Abstract

Piezoelectric crystals undergo a change in vibrational frequency proportional to a change in their mass. A sensor based on this microweighing principle was investigated for use in continuous monitoring of dissolved CO₂. The crystal coated with a primary amine was sealed into a compartment covered with a gas permeable membrane. A probe utilizing a didodecylamine coated crystal and a microporous Teflon filter membrane measured dissolved carbon dioxide in aqueous samples. A differential mode of measurement with a reference probe referred to water vapor was used to compensate for water vapor interference.     

A new antiviral pregnane from a gorgonian-derived Cladosporium sp. fungus

A new pregnane, 3α-hydroxy-7-ene-6,20-dione (1), and five known steroids (2–6), along with one known steroidal glycoside (7) were obtained from the fungus Cladosporium sp. WZ-2008-0042 cultured from a gorgonian Dichotella gemmacea collected from the South China Sea. The structure and absolute configuration of the new compound (1) were elucidated by comprehensive spectroscopic data and X-ray diffraction data. The compound has a rare configuration of 3α-OH that is different from most of pregnanes. All of the isolated compounds were evaluated for their antiviral activities against respiratory syncytial virus (RSV). Among them, 1 exhibited potential antiviral activity with the IC₅₀ value of 0.12 mM.     

An efficient synthesis of α-hydroxyphosphonates and α-aminophosphonates in the presence of chlorotrimethylsilane

Abstract

Solvent free, and quantitative yielding synthesis of α-hydroxyphosphonates (2a–h) from 2-chloroquinolin-3-carbaldehyde (1a–h) and α-aminophosphonates (4a–p) from imines (3a–p), obtained from 2-chloroquinoline-3-carbaldehyde by using triethylphosphite in the presence of chlorotrimethylsilane at room temperature in short time.     

An efficient synthesis,spectral characterization,antimicrobial, and antioxidant activities of novel α-hydroxyphosphonates and α-hydroxyphosphinates

A simple, novel, and an efficient synthesis of α-hydroxy phosphonates (3a–d) and phosphinates (5a–f) has been accomplished from febuxostat aldehyde (1) with various dialkylphosphites (2) and dialkylphosphinates (4) in the presence of 1, 4-dimethylpiperazine as a strong base with good to excellent yields (78%–95%) is reported. The structures of the title compounds were established by elemental analysis and spectral data (IR, ¹H, ¹³C and ³¹P NMR, and LC-MS). All the title compounds (3a–d) and (5a–f) were tested for their antimicrobial and antioxidant activities. Bioassay results reveal that a few of the title compounds exhibited promising antimicrobial and antioxidant activities.     

Precise and Sensitive Water Soluble Ion Extraction Method for Aerosol Samples Collected on Polytetrafluoroethylene Filters

Abstract

The widely used aerosol collection filters composed of polytetrafluoroethylene (Teflon) present a problem in the extraction of water soluble ions from the collection surface due to the hydrophobic nature of the Teflon. A method is presented for the extraction and analysis of water soluble ions from Teflon aerosol filters which is efficient and sensitive. This method uses a direct application of ethanol to the filter surface to decrease the surface tension of the filter and allow a dilute HC10, solution to contact the collection surface and extract any water soluble ions. This study compares this extraction method with other extraction methods currently being used. The results obtained from the extraction of water soluble ions from the Teflon filters were also compared to the results obtained from quartz filters collected on a colocated high volume sampler. From these studies, it is concluded that the hydrophobic nature of the Teflon filters makes the complete dissolution of water soluble ions exceptionally difficult and that the prewetting of the Teflon filters with ethanol minimizes dissolution and extraction problems.     

A Quick Color Test to Detect Lead Release From Glazed Ceramic and Enameled Metalware

Abstract

A color test is presented for the purpose of quickly identifying glazed ceramic and/or enameled metalware which releases excessive Pb. Citric acid solution on filter paper is used to extract Pb from the ware and a Pb-sensitive chromogen indicates the presence of Pb on the paper. The quick color test takes approximately 30 min and is useful for screening ware to determine the need for testing by the 24-h method of the Association of Official Analytical Chemists/American Society for Testing and Materials.     

Triterpenoids,megastigmanes and hydroxycinnamic acid derivatives from Anisomeles indica

Six triterpenoids (1–6), four megastigmanes (7–10) and five hydroxycinnamic acid derivatives (11–15) were isolated from the aerial part of Anisomeles indica (Lamiaceae). Of these components, compound 1 was identified to be a new triterpenoid with the structure of 2α,3α,19α-trihydroxyurs-12,20(30)-dien-28-oic acid based on extensive analysis of MS, 1D and 2D NMR spectroscopic data, while compounds 2–13 were obtained for the first time from Anisomeles species.     

Spectrophotometric Determination of Chromium(VI) with Cr(VI)-o-Cl-PF–TDPC Ternary Complex after Preconcentration on an Organic Solvent-soluble Membrane Filter

Abstract

A simple and rapid preconcentration technique, based on collecting trace hexavalent chromium on an organic soluble membrane filter is described. At pH 5.0, chromium(VI), o-chlorophenyl-fluorone (o-Cl-PF) and tetradecylpyridinium chloride (TDPC) form the ternary ion-associate chelate, which can be collected on a 0.2μm nitrocellulose membrane. The filter is dissolved in a small volume of dimethyl sulfoxide (DMSO) acidified with 0.15 mL 3 mol/L sulfuric acid, and the absorbance of the resulting solution is measured at 545 nm wavelength against the reagent blank. The absorbance is proportional to the content of hexavalent chromium in the range of 0.1–1.8μg, in 5 mL solvent. The sensitivity of the ternary complex reaction is very high with molar absorptivity of 1.2 × 10⁵. A detection limit better than 0.3 μg/L can be achieved. The ions normally present in water do not interfere when mixed masking agents are added. The proposed method has been applied to the analysis of water samples from several sources, the recoveries of the hexavalent chromium added to the samples are quantitative, and results found are satisfactory.     

Conversion of Alkynes into α,α-Dichloro Ketones and α,α-Dichlorodimethyl Ketals Using Trichloroisocyanuric Acid

Abstract

Trichloroisocyanuric acid reacts with alkynes in the presence of water in acetone or acetonitrile to form α,α-dichloro ketones and in methanol to form α,α-dichlorodimethyl ketals.     

New flavonoid and pentacyclic triterpene from Sesamum indicum leaves

Two new and one known compounds were isolated from the methanol extract of Sesamum indicum leaves. By means of spectroscopic methods, their structures were elucidated and identified to be 3-epibartogenic acid (1), kaempferol 3-O-[2-O-(trans-p-coumaroyl)-3-O-α-L-rhamnopyranosyl]-β-d-glucopyranoside (2) and epigallocatechin (3). Compound 1 and 3 strongly inhibited α-amylase with the IC₅₀ values of 146.7 and 303.9 μM, respectively, in comparison with acarbose (IC₅₀ 124.0 μM).     

Urinary Screen for α-Methyldopa by TLC

Abstract

A method for the detection of α-methyldopa in urine of individuals taking the drug at its therapeutic dose was developed. This test would be useful to ascertain patient compliance and to detect surreptitious use of the drug. The method is effective for detecting α-methyldopa in urine also known to contain azulfidine and/or other antihypertensive agents. No false positive or false negative analysis were obtained to date.     

pitfalls in Using Filter Paper Disks as Standard Supports In X-Ray Fluorescence Spectrometry

Abstract

Standard solutions of dimethylarsinic acid in water and methanol are deposited on Whatman No. 1 and No. 114 filter papers. The arsenic content is measured by X-ray fluorescence spectrometry. The observed specific count depends on the nature of solvents, the volume of spotting solutions, the method of spotting and the type of filter papers.     

An Investigation of Filter Types,Extraction Solvents and Storage Conditions Used for PAH Measurement in Diesel Exhaust

Abstract

A device capable of collecting simultaneously eight equivalent particulate diesel exhaust samples was constructed to test the effect of filter type, extraction solvent and storage condition on the measured concentration of five PAH compounds (fluoranthene-Ft, pyrene-Py, benz(a)anthracene-BaA, benzo(k)fluoranthene-BkFT, and benzo(a)pyrene-BaP) in diesel exhaust. An experimental design was used to most efficiently test the variables. A linear model (GLM) was used to analyze the data.     

α-Aminophosphonate derivatives of triethoxysilane for the synthesis of surface-modified silica

Abstract

A convenient synthetic route for the preparation of α-aminophosphonate derivatives of triethoxysilane, attractive precursors for silica surface functionalization, was developed. The condensation of commercially available APTES with carbonyl compounds followed by Pudovik reaction of imines with diethyl phosphite yielded desired N-phosphonomethyl functionalized (3-aminopropyl)triethoxysilanes in high yields without further purification. The chemical structures of obtained products were undoubtedly proved by ¹H, ¹³C and ³¹P NMR spectroscopy, elemental analysis and mass spectrometry.     

A Simple Microdetermination Of Polymer Flocculants (Polyacrylamides And Guar) In Mine Water

Abstract

An extremely simple, sensitive and selective microdetermination of polymer flocculants in mine water is feasible by measuring the laminar flow rate through membrane filter under vacuum.     

THE REACTION OF O-SILYLATED α-KETOLS WITH TRIMETHYLSILYL CYANIDE

Abstract

The reactions of a series of O-silylated α-ketols with trimethylsilyl cyanide have been investigated. Formation of the expected 0-trimethylsilyl cyanohydrins as major products has been shown to be accompanied by the hitherto unsuspected formation of a disiloxane by a proposed intramolecular S_N2 displacement mechanism. The latter reaction is, surprisingly, independent of the substitution pattern in the silylated ketol. Formation of the side-product, however, increases in all cases with increasing dilution. The α,β-epoxynitrile 9, a second side-product expected, along with the observed disiloxane, by our proposed mechanism was synthesized by an unambiguous route. A control experiment showed the epoxynitrile to be completely destroyed under the usual conditions of reaction with trimethylsilyl cyanide. ¹³C NMR data have been obtained for most of the compounds in this study.