Synthesis and Biological Evaluation of N,N′-di(thiopheneacetyl)diamines Series as Antitubercular Agents

The series of new N,N′-di(thiopheneacetyl)diamines derivatives, 8–17, were synthesized and evaluated for their in vitro antibacterial activity against Mycobacterium tuberculosis(TB), and the activity expressed as the minimum inhibitory concentration (MIC) in μ g/mL. Compound 13 was the only one determined to be active and exhibited a MIC 50 μg/mL, indicating that the alkyl chain-length of the diamines is critical for biological activity. This class of compound has not been evaluated before, and it could be a good starting point to find new lead compounds in the fight against multi-drug resistant TB.     

Spectrophotometry Determination of Ciprofloxacin in Serum Using Iron(III) Ion as Chromogenic Agent

ABSTRACT

An analytical procedure for the determination of ciprofloxacin in serum without previous extraction has been developed. The determination was carried out using iron(III) nitrate as chromogenic agent, with the addition of sodium dodecylsulfate, at pH = 3.0. Absorbance was measured at 430 nm. The range of linearity was between 0.5 – 20.0 μg/mL with a detection limit 0.2 μg/mL.     

Bio Availability of Polychlorinated Biphenyl Congeners in the Soil to Earthworm (L. rubellus) System

Abstract

The earthworm's (Lumbricus rubellus) uptake of polychlorinated biphenyls (PCBs) from a soil contaminated with a commercial PCB formulation (Askarel at 150 μg g^?1) and their elimination of PCBs into a low contaminated soil (15 μg g^?1) has been studied. 17 individual congeners were monitored. The uptake and the elimination rate were similar for all PCB congeners notwithstanding their different chloro-substitution pattern which suggested that bioaccumulation of PCBs in earthworms is governed by passive, possibly diffusion controlled processes. The equilibrium state in the three-phase system, soil/soil water/earthworm was reached with a half-time around 3–4 days. The soil to earthworm bioconcentration factor ranged from 4 to 20 for tetra- to octa-chlorinated biphenyls and was weakly depending on the octanol-water partition coefficient: BCF = ?(1.3?1.8) × K _OW ^(0.35?0.40).     

Anodic Stripping Potentiometric Determination of Cu,Pb, Cd and Zn In Natural Waters on a Novel Combined Electrode System

Abstract

A method is described for the reliable determination of copper, lead, cadmium and zinc in natural waters by anodic stripping potentiometry with the use of a novel combined electrode. The method involves two stripping cycles during which copper is initially determined on its own, followed by simultaneous determination of lead, cadmium and zinc after addition of gallium (III) ions. The optimum conditions include 0.01 M HCl as supporting electrolyte, 10 mg/L Hg (II) as chemical oxidant; E_dep(Cu) -700 mV vs Ag/AgCl; E_{dep(Pb,Cd,Zn)} -1200 mV vs Ag/AgCl; t_dep 10s; 150 μg/L Ga (III); sample rotation rate 5 and rest period 30s. Under these conditions, as low as 0.06 μg/L Cu (0.7% RSD); 0.2 μg/L Pb (13% RSD); 0.04 μg/L Cd (7.8% RSD) and 0.06 μg/L Zn (5.5% RSD) can be determined reliably. A linear concentration range of 0–110 μg/L was obtained for the four metals. The successful application of the method to reference fresh water, creek water and tap water is demonstrated.     

Loss of Pendimethalin in Surface Runoff from Plots Untilled and Tilled with Tobacco

Abstract

The loss of pendimethalin (N-(ethylpropyl)-2,6-dinitro-3,4-xylidine), a selective herbicide in runoff water was determined on sandy-clay-loam soil plots cultivated with tobacco in relation with the use of ammonium nitrate limestone as fertelizer, for a period of two years, 1990 and 1991. The surface slope of plots was 11% and the use of fertilizer decreased the soil erosion from a value 617 g/m²to 320 g/m². The runoff of surface waters were between 16-24% of the rainfall amounts. Reduction in pendimethalin in waterways results from water loss by infiltration, sediment loss, and by attachment adsorption on vegetative and organic matter. Surface runoff levels were highest for the first runoff event after herbicide application, 1.5 g/10 m² and initial concentrations were related to the time lapse between herbicide application and the date of the first run-off event. Maximum concentrations were 5.95 and 8.54 μg/L in 1990 and 1991 respectively. Persistence studies showed that pendimethalin concentration in runoff of 0.5 cm soil layer decreased by 88.2%, from 2.46 to 0.29 μg/g within 233 days, in 1990 and by 87.6%, from 2.42 to 0.30 μg/g within 235 days in 1991. After 310 day the concentration of pendimethalin was only 0.1 μg/g.     

Kinetic Spectrophotometric Determination of Acetaldehyde

ABSTRACT

A method for determination of trace quantities of acetaldehyde based on its inhibition effect on the malachite green-sulfite reaction is described. The reaction is monitored spectrophotometrically by measuring the decrease in absorbance at 613 nm by a fixed time method of 60 seconds. The method allows the determination of acetaldehyde in the range of 0.2-10 μg/ml. The limit of detection was 0.1 μg/ml and the relative standard deviation for ten determinations of 2 μg/ml acetaldehyde was 1.8%. The method is applied to the determination of acetaldehyde in chemical industrial waste water with satisfactory results.     

GC-ECD determination of cypermethrin and its major metabolites in soil, elm bark, and litter

An analytical method has been developed for the simultaneous determination of residues of four pairs of isomers of the pyrethroid insecticide cypermethrin, and their main metabolites, cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-cyclopropanecarboxylic acid (CCA) and 3-phenoxybenzoic acid (PBA), in elm bark, litter, and soil in the control of elm bark beetles, the vector of the Dutch elm disease. The residues of cypermethrin isomers and their metabolites were extracted with methanol under acidic conditions from elm bark, litter, and soil, cleaned up with liquid-liquid partitioning, and chromatographed by GC-ECD together after the CCA and PBA in the sample had been derivatized with α-bromo-2,3,4,5,6-pentafluorotoluene. The average recoveries of cypermethrin isomer pairs were 82 to 112% with relative standard deviations (RSDs) of 2.3 to 10% at the fortification levels of 2, 10, 100 μg/g in elm bark, 2, 15, 150 μg/g in litter, and 0.2, 2, 20 μg/g in soil. The recoveries of cypermethrin metabolites were 83 to 107% with RSDs from 2 to 12% at the fortification levels of 0.5, 5, and 10 μg/g in elm bark, and litter, and 0.1, 1, and 10 μg/g in soil.     

A High-Performance Liquid Chromatographic Approach for Monitoring Ethofumesate in Plant,Soil and Water

Abstract

A simple quantitative HPLC-UV method for the analysis of ethofumesate in fodder beet, soil and water samples is described. This method is based on a simple extraction step, gel-chromatographic and/or minisilica gel column clean up step and a separation step on a reversed phase column with uv-detection. The method is sensitive down to 10 μg/L in water and 50 μg/kg in plant and soil.

This approach shows recoveries between 90% and 110% in almost all matrices. Preliminary tests show that this method is also applicable for the analysis of ethofumesate in other plant materials.     

The Determination of Sodium Monofluoroacetate (Compound 1080) in Formulation and Technical Samples by High Pressure Liquid Chromatography

Abstract

A high pressure liquid chromatographic (HPLC) procedure was developed for the determination of sodium monofluoroacetate (Compound 1080). The procedure utilized an amine (NH₂) bonded column for the reverse phase determination of sodium monofluoroacetate in formulation and technical samples.     

Gas Chromatographic Determination of Urinary Androstanediol in Cases of Idiopatic Hirsutism

Abstract

The urinary androstanediol was determined in cases of idiopatic hirsutism by means of GLC. The determination was carried out on urines of 9 women before the beginning of a treatment with placebo and after three and six months of estrogen treatment. The initial range of values was between 39 and 99 μg/24h; at the end of the treatment the values ranged between 13 and 25 μg/24 h.

The yield of the whole procedure of determination was 70% and the detection limit was about 0.2 μg of androstanediol in urine.     

Bioanalysis of Naproxen by High Performance Reversed Phase Liquid Chromatography with Photometric and Fluorimetric Detection

Abstract

Methods for the quantitative determination of NAPROXEN and its main metabolite in plasma and urine are described. The separation is based on reversed phase liquid chromatography with LiChrosorb RP 8 (5 μm) as the support and methanol/phosphate buffer pH 7 as mobile phase, in some cases with addition of tetrabutyl ammonium ion as ion-pairing agent to improve the chromatographic selectivity. With UV-detector and a simple filter fluorometer an extraction-evaporation procedure is used for both plasma and urine determinations, while the high selectivity and sensitivity of a sophisticated fluorescence detector permits the direct injection of diluted samples on to the column. Use of an internal standard improves the within-run precision (s_rel%), which for plasma determinations of NAPROXEN are - with UV-detection, 0.2 – 1.7% (range 10 – 40 μg/ml), with filter fluorometer, 2.4 – 5.9% (range 12 – 58 μg/ml), and with fluorescence detector, 0.8 – 4.1% (range 5 – 20 μg/ml).     

Absorption Spectra of 4f Electron Transitions of Neodymium and Erbium with 8-Hydroxyquinoline-5-sulphonic Acid and Diethylamine Systems and Its Analytical Application

Abstract

In this paper the absorption spectra of 4f electron transitions of the systems of neodymium and erbium with 8-hydroxyquino-line-5-sulphonic acid and diethylamine have been studied by normal and third-derivative spectrophotometry. Their molar absorptivities are 80 l.mol^?1.cm^?1 for neodymium and 65 l.mol^?1.cm^?1 for erbium. Use of the third-derivative spectra, eliminates the interference by other rare earths and increases the sensitivity for Nd and Er. The derivative molar absorptivities are 390 1.mol^?1.cm^?1 for Nd and 367 1.mol^?1.cm^?1 for Er. The calibration graphs were linear up to 11.8 μg/ml of Nd and 12.3 μg/ml of Er, respectively. The relative standard deviations evaluated from eleven independent determinations of 7.2 μg/ml (for Nd) and 8.3 μg/ml (for Er) are 1.3% and 1.4%, respectively. The detection limits (signal to noise ratio = 2) are 0.2 μg/ml for Nd and 0.3 μg/ml for Er. The method has been developed for determining those two elements in mixture of lanthanides by means of the third-derivative spectra and the analytical results obtained are satisfactory.     

Simultaneous Determination of Norfloxacin and Tinidazole in Tablets by Reverse Phase High Performance Liquid Chromatography (RP - HPLC).

Abstract

A new simple, precise, rapid and selective HPLC-RP method has been developed for the simultaneous determination of Norfloxacin and Tinidazole in formulations, using 0.2 % Triethylamine (TEA) in water : Acetonitrile (80:20,v/v) and pH adjusted to 2.6 to 2.8 with Phosphoric acid, as a mobile phase, and C₁₈ SHODEX column (5 micron, 25 cm × 3.9 mm, ID) as stationary phase. Detection was carried out using a UV detector at 311 nm Linearity range and percentage recoveries for Norfloxacin and Tinidazole were 20 - 200 μg/mL and 30 - 300 μg/mL, 999.91 % and 99.94 % respectively.     

A new isoprenyl phenyl ether compound from mangrove fungus

A new isoprenyl phenyl ether, 3-hydroxy-4-(3-methylbut-2-enyloxy)benzoic acid methyl ester (1), together with 4-hydroxybenzoic acid (2), 2-hydroxy-6-methylbenzoic acid (3), and 4-hydroxy-3-methoxybenzoic acid (4) were isolated from Mangrove fungus (No. B60) from the South China Sea. The structures of the compounds were established on the basis of NMR spectroscopic and mass spectrometric data. In the preliminary bioassay, compound 1 exhibited antibacterial and antifungal activities. Compound 1 also inhibited cytotoxicity to the hepG2 cell line with an IC₅₀ value of 10.0 μg/mL. Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 313–314, July–August, 2007.     

High Pressure Liquid Chromatographic Determination of Mecillinam in Human Plasma and Urine

Abstract

A simple, specific, rapid and sensitive method for the analysis of mecillinam in plasma and urine using high pressure liquid chromatography is described. The assay is performed by direct injection of a plasma protein free supernatant or a dilution of urine. A μBondapak phenyl column with an eluting solvent of 16% CH₃CN-0.2% H₃PO₄ was used, with UV detection of the effluent at 220 nm. Desacetyl-cephalothin was used as the internal standard and quantitation was based on peak height ratio of mecillinam to that of the internal standard. The lowest concentration detectable without extraction was 0.25 μg/ml for plasma and 8.9 μg/ml for urine. No interference from plasma and urine was noted.     

Some Arylidene-2-Pyridylhydrazone Derivatives as Reagents for Spectrophotometric Determination of Palladium (II)

Abstract

A method for spectrophotometric determination of palladium by complexation with Arylidene-2-pyridylhydrazone derivatives in 50% (V/V) ethanolic solution are described-Pd(II) forms a 1:1 complex with the reagents. Beer's law is obeyed over the range 0.2-6.5 μg ml^?1. The effect of pH, effect of excess reagent, stability of complexes as well as the tolerance amount of many metal ions have been reported. The method is applied, with fair accuracy, to the determination of pd(II) in synthetic solutions.     

Influence of Air Velocity,Application Dose,and Test Area Size on the Volatilisation of Lindane

Abstract

The volatilisation of lindane from soil and French beans was tested in a wind tunnel under defined conditions. Volatilised lindane was determined directly by passing a partial air stream through an adsorbent. Applications of a lindane formulation onto soil and plant surfaces were performed using a moving nozzle.

Soil volatilisation experiments were conducted using different air velocities (0.4, 1.1, 1.7 m/s). At higher air velocities the volatilisation rate increased from 12% to 31% within 24 h (initial dose 100%). For plant experiments with different velocities (0.4,1.0,2.0 m/s) the volatilisation rate increased from 52% to 62% at the highest velocity. Additionally, as higher air velocities were applied, air concentrations of lindane during the first hour decreased from 1.61 μg/m3 at 0.4 m/s to 0.61 μg/m3 at 2.0 m/s.

In soil experiments with different application doses of lindane (33 mg/m², 117 mg/m²) the volatilisation rate was decreased (23%) at the higher application dose in comparison to the lower dose (39%). The volatilisation rate was also influenced by the size of the treated area in the wind tunnel. From a larger soil surface (0.84 m2) a lower amount of lindane (23%) volatilised than from a smaller surface (31% at 0.28 m).     

Determination of Total Selenium in Human Urine and Serum by Graphite-Furnace Atomic-Absorption Spectrophotometry with Palladium-Nickel-Ammonium Nitrates as a Matrix Modifier

After human urine or serum was diluted (1 + 9) with HNO₃ (0.2%, v/v) and standard additions of Se solution (100 μ L^?1), the diluted sample (10 μL) was introduced into the graphite cuvette. The matrix modifier [10μL, containing Pd (0.6 μg) + Ni (25 μg) + NH₄NO₃ (80 μg) in HNO₃ (0.2%, v/v) for urine, or Pd (0.3 μg) + Ni (30 μg) + NH₄NO₃ (80 μg) + Triton X-100 (0.04%) in HNO₃ (0.2%, v/v) for serum, respectively] was added and the mixture was heated according to a temperature program. The matrix modifier containing NH₄NO₃ in a suitable amount and a small amount of Pd enhanced the sensitivity for Se. The method detection limits (3σ) after dilution were about 4.9 ± 0.8 and 2.36 ± 0.18 μg L^?1 for urine and serum, respectively. The accuracy of this method was tested with SRM #2670 human urine Se and Seronorm Trace Elements #116 human serum Se, respectively, and the results of 97.6 – 101% and 100 – 104% were obtained with precision ± 0.3% and ± 2%, respectively. This method can be applied easily and accurately to the determination of concentration of total Se in human urine and serum.     

The impact of nitrogen fertilizers on degradation and leaching of chlorotoluron in soil

Abstract

This study presents the developed and applied methods for the determination of carbendazim in environmental samples originating from several field studies.

For water samples sample pretreatment consisted of a solid phase extraction (SPE) on cartridges packed with 200 mg SDB-1. In case of solid samples the performance of microwave assisted solvent extraction (MASE) and classical ultrasonic extraction with acetone-ethyl acetate were studied. The latter technique was selected because of the reduced time of manual operations. Instrumental analysis of extracts of water samples was performed on-line with coupled column reversed phase liquid chromatography (LC/LC) and UV detection (280 nm) allowing to assay carbendazim to a level of at least 0.1 μg/l. Improved column life time was obtained by performing the favorable LC separation of carbendazim at high pH on newly developed 5 μm Extend-pH bidentate C18 material.

The combination of a short column packed with 5 μm Inertsil ODS-5 and a mobile phase at low pH material was most adequate as the regards the robust and fast processing of extracts of solid samples and allowed in most cases the screening of carbendazim in soils and sediments to a level of 10μg/kg.

The developed procedures yield overall recoveries for carbendazim of 101, 80 and 71 % in water (levels, 0.1—1.2 μg/l: n=12), soil (levels, 10 and 100 μg/kg; n=22) and sediments (levels, 10 and 100 μg/kg; n=11), respectively, with a repeatability and reproducibility below 7 % for all method/matrix combinations. Soil samples with aged residues (level, 100 μg/kg; n=10) provided an overall recovery of 71% and no significant decrease of carbendazim was observed during nine weeks of storage in the refrigerator.     

Metabolism of Ecdysteroids During the Embryogenesis of Manduca Sexta

Abstract

The combination of ion suppression, reverse phase high pressure liquid chromatography (IS-RPHPLC) and radioimmunoassay (RIA) employing two relatively non-specific, complimentary antisera was used to identify and quantify ecdysteroids of divergent polarities during embryogenesis of the tobacco hornworm, Manduca sexta. Newly layed eggs (0–1 hr) contained high levels (>30 μg/g) of a maternally derived, polar conjugate of 26-hydroxy-ecdysone (26E) but less than 0.6 and 0.2 μg/g of the polar conjugates of ecdysone (E) and 20-hydroxyecdysone (20E), respectively. The only free ecdysteroid detected was 26E (0.4 μg/g). Between 4 and 12 hr after oviposition, marked deconjugation activity occurred as titers of free 26E increased to 14 μg/g while levels of conjugated 26E fell to 19 μg/g. By this time there were only negligible levels of free E (less than 0.1 μg/g). After 12 hr, the deconjugation of the maternal polar 26E-26-phosphate conjugate slowed and levels of free 26E fell as it was metabolized. At 24 hr, low titers of free 20,26-dihydroxyecdysone (20,26E, 0.4 μg/g) and a β-D-glucose conjugate of 26E (0.8 μg/g) were detected, presumably formed by embryonic 20-monooxygenase and uridine diphospho-α-D-glucose (UDPG) glucosyltransferase activities, respectively. About the time of the deposition of the first larval cuticle (66–72 hr), these 26E metabolites reached high concentrations, (5 μg/g free 20,26E and 7 μg/g 26E-glucose conjugate) while free 26E fell to 2 μg/g. In newly hatched larvae, the 26E-glucose conjugate was the major detectable ecdysteroid. At no time during embryogenesis did the concentrations of free E and 20E exceed 0.5 μg/g and 0.3 μg/g, respectively.