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A rapid, selective and sensitive method for the quantification of Pd (II) using spectrophotometric technique associated with Z-N'-(benzo(d) thiazol-2-yl)-N,N-dimethylformimidamide BTDF as new chelating agent is described. Yellow colored complex of Pd (II) with BTDF is formed in Britton-Robinson universal buffer of pH 9 and extracted with chloroform. The formed complex clearly illustrate an absorption at ∼384 nm and follw Beer’s law in the range of concentration between 0.5–18.0 µg ml−1 of Pd (II) with absorbance of 3.62 × 104 L mol-1 cm-1 and limit of detection(LOD) of Pd (II) 0.07 µg ml−1. The effects of different experimental parameters have been established by study the optimum conditions for the extraction and quantification of palladium ion. Density functional theory (DFT) havealso been employed to computethe influence of the cation on theoretical parameters of Pd2+ complexes. The effect of donating centers was investigated theoretically which prove that Pd2+ favor coordinated with two molecules of Z-N'-(benzo(d)thiazol-2-yl)-N,N-dimethylformimidamide through two nitrogen atoms.The performance of the examined method was estimated to detect the impact of current method over the presented methods in the literature without interference effect of cations and anions. The examined method has successfully demonstrated the quantification of Pd(II) in natural and spiked water samples.

Two different techniques are developed for the determination of clopidogrel in pharmaceutical preparations. HPLC method has been developed where chromatographic analysis is performed on Nova-Pak(superscript ®) C18 column (3.9 mm×150 mm, 5 μm) with an ammonium formate buffer adjusted with formic acid to pH 4.0, acetonitrile (40:60, v/v) as mobile phase, and detection at 225 nm. Good linearity (0.9993, r), accuracy (≥99.20%) and precision (≤0.6 RSD) were obtained. Potentiometric measurments are based on tetrakis (p-chlorophenyl) borate-clopidogrel ion-pair as an electroactive material incorporating a plasticized PVC membrane with o-nitrophenyl octyl ether or dioctyl phthalate. The sensor is conditioned for at least two days in 0.1 M drug solution before use. It exhibits fast and stable Nernstian response for clopidogrel over the concentration range of 1.0×10^(-5)~1.0×10^(-2) M and pH range of 1.5-4.0. Results with an average recovery of 100.6% and a mean standard deviation of 0.86% of the nominal were obtained. The sensor shows reasonable selectivity towards clopidogrel hydrogen sulphate in presence of many cations. No significant interferences are caused by drug excipients and diluents.

Melatonin is an indolic compound that has been reported in the literature to exist in human-based samples, vertebrates, vegetables, fruits, and pharmaceutical products. Melatonin is considered a dietary supplement and can regulate circadian rhythms, although it has not been classified as a drug by the US Food and Drug Administration. Several analytical methods have been used for its detection. This study aimed to summarize the recent outcomes of the chromatographic methods such as electrophoretic methods, gas chromatography, and liquid chromatography, which have been used for the determination of melatonin in the last three decades, with the focus on gas chromatography and high-performance liquid chromatography methods.

This study involves the preparation and investigation of a novel and highly selective poly(vinyl chloride)-based membrane of 2-((5-(2-hydroxy-3-methoxybenzylideneamino)-2H-1,2,4-triazol-3-ylimino)methyl)-6-methoxyphenol Schiff base ligand (HMBT), which is a neutral ionophore with sodium tetraphenyl borate (STB) in the form of an excluder and o-nitrophenyloctyl ether (o-NPOE) in the form of solvent mediators (plasticizing) as a Ni(II)-selective electrode. The observation of optimal performance was done wherein the membrane was shown to have the HMBT–PVC–NPOE-STB composition of 4:32:63:1.It worked effectively across a broad range of concentration (1.0 × 10−8 to 1.0 × 10−2 mol L−1). Meanwhile, the Nernstian slope was recorded as 29.3 mV per decade of activity between pH 3.0 and 8.0. The response time of this electrode was fast at 11 s which was used for a span of 100 days with sound reproducibility. According to the selectivity coefficients for trivalent, divalent, and monovalent cations, excellent selectivity was indicated for Ni(II) ions across a large number of citations, whereas no interference was caused by anions like PO43-, SO42− and Cl−. The proposed method in this study was applied successfully to determine Ni(II) content in different samples of water, obtaining suitable recoveries. Additionally, the probed sensor is utilized as indicator electrode when considering Ni2+ ion potentiometric titration against EDTA. In addition, the chelate’s geometry and structure of the complex formed between Ni2+ ions and HMBT, abbreviated as HMBT-Ni2, was evaluated by separating the solid product. Complex structure was confirmed based on alternative analytical and spectral methods to be structured in the bimetallic form with the formula [Ni2(HMBT)(H2O)2 Cl2]. The diamagnetic nature of the complex, which was concluded from the room temperature magnetic moment measurement combined with the UV-Vis measurement, suggested the square planar geometry around the Ni centers.

A simple methods have been developed for determination of Cu(II) ions in aqueous solutions. The spectrophotometric method relied mainly on the reaction between Cu(II) ions and the azo dye ligand named N-diaminomethylene-4-(2,4-dihydroxy-phenylazo)-benzenesulfonamide (H2L) at pH 10.0. The influence of parameters such as concentration, pH and reaction time were inspected. A linear relationship (R2 = 0.9992) between absorbance and the concentration of Cu(II) was obtained at the maximum absorption peak of 474 nm within 1.6–9.6 × 10−6 mol L−1 concentration range. The limit of detection for Cu(II) ion and limit of quantitation were 1.1 × 10−7 mol L−1 and 3.7 × 10−7 mol L−1, respectively. The potentiometric method is based on a novel poly(vinyl chloride) membrane, containing the synthesized azo dye as an ionophore, was used to developed a Cu(II)- selective sensor. This newly developed sensor revealed a Nernstian response over Cu2+ ion in a concentration range 1.0 × 10−6–1.0 × 10−2 mol L−1 with cationic slopes of 29.5 ± 0.2 mV decade−1 and detection limits of 3.0 × 10−6 mol L−1 copper(II) for o-nitrophenyl-octyl ether (o-NPOE) based membrane sensor. The electrode showed good discrimination toward Cu2+ ions with respect to most common cations. The advantages of the proposed methods are their simplicity, selectivity, and high sensitivity. In addition, the sensor has been used as indicator electrode in the potentiometric titration of Cu2+ ion against EDTA. The structure and geometry of the complex formed between Cu(II) and H2L ligand was identified via isolation of the solid complex; Co(II) an Ni(II) complexes were synthesized as well. The geometrical structure around the metal centers were proved to be square planar for Cu(II) complex and tetrahedral for Co(II) an Ni(II) complexes.

Three neurotransmitter sensors for dopamine, serotonin, and epinephrine have been developed. Potentiometric sensors for serotonin and epinephrine are novel and first to be introduced. The neurotransmitter potentiometric sensors are based on using dibenzo-30-crown-10 (DB30C10), dibenzo-24-crown-8 (DB24C8), and dibenzo-18-crown-6 (DB18C6) as ionophores and neutral carriers incorporating in poly(vinyl chloride) matrix membrane plasticized with o-nitrophenyl octyl ether. Sensors based on dibenzo-30-crown-10 show good responses for the dopamine, serotonin, and epinephrine (Type I–III, respectively) with a cationic slope of 57.9 mV decade−1 and detection limit of 4.0×10−5 mol L−1 dopamine, cationic slope of 55.9 mV decade−1 and detection limit of 4.0×10−5 mol L−1 serotonin, and cationic slope of 54.4 mV decade−1 and detection limit of 2.0×10−5 mol L−1 epinephrine. The sensors based on DB24C8 and DB18C6 (Types IV–IX) show poor responses in terms of calibration range and slope. The effect of the interferents on the response of the sensors reveals a high selectivity for the neurotransmitters over many inorganic cations, ascorbic and uric acids. The useful pH range for the three sensors is 3–7, the response time is fast (11 s), and the life span is long (2.5 months). Sensors (Types I and III) are successfully used for the quantification of dopamine and adrenaline in pharmaceutical preparations.

A new and rapid potentiometric method to quantify aluminum ions concentration was developed. The method involves the development of an aluminum ion sensor with a membrane consists of diethyl (2-azobenzoic acid) malonate (DAM) as a novel ionophore in poly (vinyl chloride) matrix membrane plasticized with orthonitrophenyl-octyl ether or dioctylphthalate. The structure of the synthesized ionophore (DAM) was identified using Fourier transform infrared, 1H Nuclear magnetic resonance, and elemental analysis. The proposed electrode reveals a Nernstian response over Al3+ ion in a concentration range $1\times 10^{\mathrm {-7}}$ – $1\times 10^{\mathrm {-2}}$ mol $\text{L}^{\mathrm {-1}}$ with the cationic slopes of 19.6 ± 0.3 and 19.3 ± 0.2 mV decade $^{\mathrm {-1}}$ , and the limits of detection $5 \times 10^{\mathrm {-8}}$ and $7 \times 10^{\mathrm {-8}}$ mol $\text{L}^{\mathrm {-1}}$ aluminum(III) for orthonitrophenyl-octyl ether and dioctylphthalate-based membrane sensors, respectively. The electrodes showed good discrimination toward Al3+ ion in the presence of the most common cations. The electrodes show response in a short time (10 s) for the entire concentration range and used for 11 weeks without significant variation in potentials. To evaluate the application of the investigated electrodes was used to determine Al3+ ion at different collected samples from environmental sources. In addition, these sensors have been used as indicator electrodes in the potentiometric titration of Al3+ ion against Ethylenediaminetetraacetic acid.

The characteristics, performance and application of ion-selective electrodes for bromate ion based on rhodamine B and tetrahexyl ammonium bromide as electrode-active substances are described for the first time. These electrodes respond with sensitivities of (58.0±1.0) and (61.0±2.0) mV decade−1 over the range 1.0×10−8–1.0×10−2 mol l−1 at pH 4–9 and 4–8 and a detection limit of 6.0×10−8 and 4.0×10−8 mol l−1 for rhodamine B and tetrahexyl ammonium bromide sensors, respectively. The electrodes are easily constructed at a relatively low cost, have a fast response time and can be used for a period of 3 months without any considerable divergence in potential. The proposed sensors displayed good selectivity for bromate ion in the presence of several substances and inorganic anions. Sensors were used for the direct assay of bromate ion in drinking water samples.

The present article reports for the first time the use of Aliquat 336S-atorvastatin as an electroactive material in a poly(vinyl chloride) matrix membrane sensor plasticized with ortho-nitrophenyl-octylether (o-NPOE) or dioctylphthalate (DOP) for determination of atorvastatin in biological samples (human plasma) and in pharmaceutical preparations. The sensor shows fast, stable and reproducible response over the concentration range of 1.0×10−7–1.0×10−2 mol L−1 atorvastatin with anionic slopes of 60.94±0.2 and 58.22±0.2 and pH range of 5.0–9.0 for o-NPOE and DOP plasticized based membrane sensors, respectively. The response time of the sensor is stable and fast (10 s). Results were achieved with average recoveries of 99.5 % and 99.3 % and mean standard deviations of ±1.1 % and ±1.4 % for o-NPOE and DOP plasticized based membrane sensors, respectively. The sensor exhibits high selectivity towards atorvastatin in the presence of many anions, drug excipients and diluents. Validation of the method according to the quality assurance standards shows suitability of the proposed sensors for use in the quality control assessment of the drug.

A new and rapid potentiometric method for determination of flucloxacillin is developed. The method involves development of a flucloxacillin sensor with a membrane consisting of Aliquat 336S-flucloxacillin as an electroactive material in poly vinyl chloride matrix membrane plasticized with orthonitrophenyl-octylether or dioctylphthalate. The sensor shows fast, stable and reproducible response over the concentration range of 1.0 × 10 −5 –1.0 × 10 −2 M flucloxacillin with anionic slopes of 60.7 ± 0.3 and 61.2 ± 0.2 and pH ranges of 6–11 and 7–11 for o -nitrophenyloctylether ( o -NPOE) and dioctylphthalate (DOP) plasticized based membrane sensors, respectively. The response time of the sensor is stable and fast (7 s). The sensor exhibits high selectivity towards flucloxacillin in presence of amoxicillin, ampicillin, dicluxacillin, pencillin, many anions and drug excipients and diluents. Validation of the method according to the quality assurance standards shows suitability of the proposed sensors for use in the quality control assessment of the drug. Results with average recoveries of 99.6% and 99.7% and mean standard deviations of ±1.2% and ±1.5% for o -NPOE and DOP plasticized based membrane sensors, respectively, of the nominal are obtained which compare fairly well with data obtained using the British Pharmacopoeia method.

The litterfall is the major organic material deposited in soil of Brazilian Caatinga biome, thus providing the ideal conditions for plant biomass-degrading microorganisms to thrive. Herein, the phylogenetic composition and lignocellulose-degrading capacity have been explored for the first time from a fosmid library dataset of Caatinga soil by sequence-based screening. A complex bacterial community dominated by Proteobacteria and Actinobacteria was unraveled. SEED subsystems-based annotations revealed a broad range of genes assigned to carbohydrate and aromatic compounds metabolism, indicating microbial ability to utilize plant-derived material. CAZy-based annotation identified 7275 genes encoding 37 glycoside hydrolases (GHs) families related to hydrolysis of cellulose, hemicellulose, oligosaccharides and other lignin-modifying enzymes. Taxonomic affiliation of genes showed high genetic potential of the phylum Acidobacteria for hemicellulose degradation, whereas Actinobacteria members appear to play an important role in celullose hydrolysis. Additionally, comparative analyses revealed greater GHs profile similarity among soils as compared to the digestive tract of animals capable of digesting plant biomass, particularly in the hemicellulases content. Combined results suggest a complex synergistic interaction of community members required for biomass degradation into fermentable sugars. This large repertoire of lignocellulolytic enzymes opens perspectives for mining potential candidates of biochemical catalysts for biofuels production from renewable resources and other environmental applications.

This study reports that ongoing in situ anaerobic hydrocarbon biodegradation at a manufactured gas plant impacted site is occurring, 9 years after the initial investigation. Groundwater samples from the site monitoring wells (MW) were analyzed for biomarkers by GC-MS, end-point PCR, and quantitative PCR (qPCR). Metabolic biomarkers included specific intermediates of anaerobic naphthalene and/or 2-methylnaphthalene degradation: 2-naphthoic acid (2-NA); 5,6,7,8-tetrahydro-2-NA (TH-2-NA); hexahydro-2-NA (HH-2-NA); and carboxylated-2-methylnaphthalene (MNA). The analogues of gene bssA, encoding alpha subunit of enzyme benzylsuccinate synthase, were used as a genetic biomarker. Results indicate 1-2 orders of magnitude higher abundance of total bacteria in the impacted wells than in the unimpacted wells. End-point PCR analysis of bssA gene, with degenerate primers, indicated the presence of hydrocarbon degrading bacteria within the plume. In qPCR analysis, using primers based on toluene-degrading denitrifying or sulfate-reducing/methanogenic bacteria, bssA genes were detected only in MW-24, located downstream from the source. Metabolic biomarkers were detected in multiple wells. The highest abundance of 2-NA (6.7 μg/L), TH-2-NA (2.6 μg/L), HH-2-NA, and MNA was also detected in MW-24. The distribution of two independent biomarkers indicates that the site is enriched for anaerobic hydrocarbon biodegradation and provides strong evidence in support of natural attenuation.

Simple, selective and accurate sensors were developed for the determination of melatonin and oxomemazine in biological samples (urine) and in pharmaceutical preparations. Potentiometric measurements were based on bismus tetraiodate-drug ion-pair as novel electroactive materials incorporating a plasticized PVC membrane with o-nitrophenyl octyl ether or dioctyl phthalate. Each sensor was conditioned for at least two days in 0.1 M drug solution before use. It exhibited fast and stable Nernstian response for melatonin and oxomemazine over the concentration range of 1.0×10−6–1.0×10−2 M and 1.0×10−5–1.0×10−2 M, pH range of 3.0–6.5 and 3.5–6.0 for melatonin and oxomemazine sensors, respectively. Results with an average recovery not more than 101 % and a mean standard deviation less than 1.0 % of the nominal were obtained for the four sensors. The sensors showed reasonable selectivity towards investigated drugs in presence of many cations.

An instrumental setup including on-line solid phased extraction coupled to capillary liquid chromatography-electrospray ionization-mass spectrometry (SPE-capLC-ESI-MS) has been constructed to improve the sensitivity for quantification of fluoxetine hydrochloride in human plasma. Prior to injection, 0.5 mL of plasma spiked with metronidazole (internal standard) was mixed with ammonium formate buffer for effective chloroform liquid-liquid extraction. The method was validated in the range 5-60 ng mL(-1) fluoxetine, yielding a correlation coefficient of 0.999 (r(2)). The within-assay and between-assay precisions were between (8.5 and 11%) and (6.6 and 7.5%), respectively. The method was used to determine the amount of fluoxetine in a healthy male 14 h after an intake of one capsule of the antidepressant and anorectic Flutin, which contains 20mg fluoxetine per each capsule. Fluoxetine was detected, and the concentration was calculated to 9.0 ng mL(-1) plasma. In the preliminary experiments, conventional LC-UV instrumentation was employed. However, it was found that employing a capillary column with an inner diameter of (0.3mm I.D. x 50 mm, Zorbax C(18)) increased the sensitivity by a factor of approximately 100, when injecting the same mass of analyte. Incorporating an easily automated C(18) reversed phase column switching system with SPE (1.0mm I.D. x 5.0mm, 5 microm) made it possible to inject up to 100 microL of solution, and the total analysis time was 5.5 min.

Three simple, sensitive, and highly accurate spectrophotometric methods have been developed for the determination of oxomemazine hydrochloride (OXO‐HCl) in bulk and in pharmaceutical formulations. These methods are based on the formation of yellow ion‐pair complexes between the examined drug and bromocresol green (BCG), congo red (CR), and methyl orange (MO) as reagents in universal buffer solution of pH 3.0, 5.5, and 3.5, respectively. The formed complexes were extracted with chloroform and measured at 413, 495, and 484 nm, respectively for the three systems. The best conditions of the reaction were studied and optimized. Beer's law was obeyed in the concentration ranges 2.0–18.0, 2.0–14.0, and 2.0–16.0 µg ml−1 with molar absorptivity of 4.1×104, 1.1×104, and 3.5×104 mol−1cm−1, for the BCG, CR, and MO methods, respectively. Sandell's sensitivity, correlation coefficient, detection, and quantification limits are also calculated. The proposed methods have been applied successfully for the analysis...

A method based on on‐line solid phased extraction capillary liquid chromatography‐electrospray ionization‐mass spectrometry (SPE‐capLC‐ESI‐MS) has been developed for the determination of oxomemazine in human plasma. Prior to injection, 0.5 mL of plasma spiked with metronidazole (internal standard) was mixed with ammonium formate buffer and methyl orange, which served as an ion pair reagent for effective chloroform liquid–liquid extraction. The employment of methyl orange as an ion pair reagent doubled the extraction efficiency, as compared to not using methyl orange. In preliminary experiments, conventional LC‐UV instrumentation was employed. However, it was found that employing a capillary column with an inner diameter of 0.3 mm increased the sensitivity by a factor of ∼100, when injecting the same mass of analyte. Incorporating an easily automated reversed phase column switching system with SPE made it possible to inject up to 100 µL of solution, and the total analysis time was 5 minutes. The m...

An investigation of lakebed sediment found elevated polycyclic aromatic hydrocarbon (PAH) levels, and a nearby former manufactured gas plant (MGP) site was identified as the most likely source. Forensic chemistry or “chemical fingerprinting” was conducted on sediment samples from a boat slip in the vicinity of the MGP and on-shore soil samples from the MGP property in order to determine whether or not the former MGP was the origin of the PAHs found in the sediment. An analysis of the data from gas chromatography with flame ionization detection (GC/FID) and mass spectrometry (GC/MS) suggested that the PAH distributions measured in the sediment samples were similar to those measured in samples of tarry soil from the former MGP site. However, because of the urban and industrial land use surrounding the former MGP site, it was also possible that there was a PAH contribution to the sediments from urban runoff or other industrial and municipal discharges. The compound-specific isotope ratios (CSIRs) of carbon i...

A potentiometric poly(vinyl chloride) membrane sensor for determination of saccharin is described. It is based on the use of Aliquat 336S-saccharinateion-pair as an electroactive material in plasticized PVC membranes with o-nitrophenyloctylether or dioctylphthalate. The sensor is conditioned for at least two days in 0.1 mol L−1 sodium saccharinate before use. It exhibits fast, stable and Nernstian response for saccharinate ions over the concentration range of 1.0 × 10−1–5.0 × 10−5 mol L−1 and pH range of 4.5–11. The sensor is used for determination of saccharin in some dosage forms. Results with an average recovery of 101% and a mean standard deviation of 0.2% are obtained which is compared favourably with data obtained using the British pharmacopoeia method. The sensor shows reasonable selectivity towards saccharin in presence of many anions and natural sweeteners.

Recent trends in environmental remediation have increasingly employed the use of environmental chemistry techniques to decipher the source(s) and fate of the contaminants and, in some cases, to determine their age or apportion them to sources. An extensive database of pyrogenic and petrogenic 'chemical fingerprints' has been constructed by the Gas Technology Institute (GTI) and META Environmental, Inc. using gas chromatography coupled with a flame ionization detector (GC/FID) or with a mass spectrometer (GC/MS). The use of these chemical fingerprinting techniques have been highly successful in discerning wastes from wholly different sources as well as among Manufactured Gas Plant (MGP)-type wastes from different plant operations. However, these techniques have been limited when low-level polycyclic aromatic hydrocarbon (PAH) discernment is required. Specifically, these techniques often do not provide data with sufficient conclusive discriminating power between the 'urban background'PAH sources and those from MGP-operations, which is pertinent for meeting low-level, stringent site-cleanup standards. GTI has been developing a new analytical method for the measurement of 'urban background' PAH contamination. This method measures the compound-specific isotope ratio (CSIR) carbon with a GC/IRMS (isotope ratio mass spectrometer). The GC/IRMS technique is a relatively new analytical tool that has great potential as an environmental forensic method at former MGP sites. This paper focuses on the applications of both chemical and isotopic analysis of samples to discern PAH contamination in the environment.

The effect of thermal treatments on both the Morin transition and the spin flop field (Hsf) of α-Fe2O3 acicular particles (major axis:(350 ± 50) nm; minor axis: (85 ± 15) nm.) has been investigated by means of magnetization vs temperature-magnetic field measurements. Both the Morin transition and the spin flop process have been observed only after an annealing treatment at 500 °C. Due to the finite size effect, the values of the Morin temperature and spin-flop field are significantly below the bulk value.

A sensitive, selective and rapid method has been developed for the determination micrograms per liter level of vanadium ion based on the rapid reaction of vanadium(V) with 2,3-dichloro-6-(2,7-dihydroxy-1-naphthylazo)quinoxaline (DCDHNAQ) and the solid phase extraction of the colored complex with C18 cartridge. The DCDHNAQ reacts with V(V) in the presence of citric acid-sodium hydroxide buffer solution (pH 3.3) and benzyldimethyl tetradecylammonium chloride (zephiramine) medium to form a violet complex of a molar ratio 1:2 [V(V) to DCDHNAQ]. This complex was enriched by solid phase extraction with C18 cartridge and the enrichment factor of 100 was obtained by elution of the complex from the cartridge with acetonitrile. The molar absorptivity and Sandell sensitivity of the complex are 2.45x10(5) L mol(-1) cm(-1) and 0.0208 ng cm(-2) at 573 nm in the measured solution. Beer's law is obeyed in the range of 0.01-0.45 microg mL(-1), whereas Ringbom optimum concentration ranges found to be 0.025-0.425 microg mL(-1). The detection and quantification limits are 3.2 and 9.9 microg L(-1), respectively in the original samples. This method was applied to the determination of vanadium(V) in steel, soil, water and biological samples with good results.

Indomethacin-treated bovine iris-ciliary body microsomes (IBIM) have been studied for their ability to convert PG endoperoxides into either thromboxane-A2 (TxA2)-like or prostacyclin (PGI2)-like activity. The biological activity of the ocular tissue microsomes were compared with either indomethacin-treated human platelet microsomes (for TxA2-like activity) or rabbit aorta microsomes (for PGI2-like activity) under appropriate incubation conditions. No evidence could be found for the formation of TxA2-like activity from PG endoperoxides by the IBIM. In contrast, when the IBIM were incubated with PGH2 for 1 min at 22 degrees C without cofactors, PGI2-like activity was produced, causing profound relaxation of the isolated dog coronary artery preparation without contracting the rabbit aorta and inhibiting arachidonic acid-induced platelet aggregation. Equivalent quantities of boiled IBIM failed to alter the biological activity of PGH2 under identical conditions. Tranylcypromine (500 microgram/ml) completely abolished the appearance of PGI2-like activity. Furthermore, the PGI2-like activity found was stable for 10 min at 22 degrees C at pH 8.5 but completely lost under similar conditions at pH 5.5. It is concluded that microsomal preparations of normal bovine iris-ciliary body can synthesize PGI2-like activity in substantial amounts but not TxA2-like activity.

Bacteria able to mineralize 100 to 200 ppm of pentachlorophenol (PCP) were isolated by selective enrichment from PCP-contaminated soils from three geographic areas of Minnesota. Although differing somewhat in their responses to various biochemical and biophysical tests, all strains were assigned to the genus Flavobacterium. Five representative strains were examined in detail. All strains metabolized PCP as a sole source of carbon and energy; 73 to 83% of all carbon in the form of [U-14C]PCP was returned as 14CO2, with full liberation of chlorine as chloride. A comparison between strains in their ability to metabolize PCP showed some strains to be more efficient than others. Guanine-plus-cytosine contents of DNA ranged from 58.8 to 63.8%, and DNA/DNA hybridization studies with total DNA digests suggested substantial genetic homology between strains. All strains were shown to possess an 80- to 100-kilobase plasmid, and evidence suggested the presence of a larger plasmid (greater than 200 kilobases).