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To better understand the photodegradation of polycyclic aromatic hydrocarbons (PAH) in solid phase in natural environment, laboratory experiments were conducted to study the influencing factors, kinetics and intermediate compound of pyrene photodegradation by iron oxides. The results showed that the pyrene photodegradation rate followed the order of α-FeOOH>α-Fe2O3 >γ-Fe2O3 >γ-FeOOH at the same reaction conditions. Lower dosage of α-FeOOH and higher light intensity increased the photodegradation rate of pyrene. Iron oxides and oxalic acid can set up a photo-Fenton-like system without additional H2O2 in solid phase to enhance the photodegradation of pyrene under UV irradiation. All reaction followed the first-order reaction kinetics. The half-life (t 1/2) of pyrene in the system showed the higher efficiencies of using iron oxide as photocatalyst to degrade pyrene. Intermediate compound pyreno was found during photodegradation reactions by gas chromatography–mass spectrometry (GC–MS). The photodegradation efficiency for PAHs in this photo-Fenton-like system was also confirmed by using the contaminated soil samples. This work provides some useful information to understand the remediation of PAHs contaminated soils by photochemical techniques under practical condition. [Copyright &y& Elsevier]

AbstractAim:The aim of this study was to design and synthesize a series of high activity compounds against aspartyl protease β-secretase (BACE-1) bearing hydroxyethylene (HE) framework.Methods:First, we designed the small library based on our previous work and rational analysis. Subsequently, thirteen compounds were selected and synthesized using skilled solid phase synthetic methods to explore the relationship between structure and activity. We then used molecular modeling to explain the possible binding mode.Results:Thirteen new compounds (6-18) have been designed, synthesized and bioassayed. Their structures were determined by nuclear magnetic resonance (NMR) spectra, low- and high-resolution mass spectra and optical rotation. Most compounds have shown moderate to excellent activities, and compound 10, which contains fewer amino acids and amide bonds than GRL-7234, was about 5-fold more potent than the control compound 4 discovered by Merck. The molecular modeling results have indicated the possible binding mode and explained the difference between compounds 10 and 16, providing direction for further study.Conclusion:This study yielded several high activity compounds bearing fewer amino acids and amide bonds than previous compounds, providing insight into the further development of potent BACE-1 inhibitors for the treatment of Alzheimer's disease.Acta Pharmacologica Sinica (2009) 30: 259–269; doi: 10.1038/aps.2008.26; published online 26th January 2009 [ABSTRACT FROM AUTHOR]

Abstract: In this work, the monoclonal antibodies (McAbs) to α-fetoprotein (AFP) were immobilized on two different solid phases, i.e., magnetic particles (MP) and coated tubes (CT). Based on this, a MP based chemiluminescence enzyme immunoassay (MP-CLEIA) and a CT based CLEIA (CT-CLEIA) were proposed for the evaluation of AFP in human serum and their analytical merits were studied and compared. By detailed discussion of several performance variants, including the concentration of immobilized McAb, dilution ratio of horseradish peroxidase (HRP) labeled McAb (HRP-McAb), total assay time, substrate volume, chemiluminescent kinetics, and hook effect concentration, the advantages of MP-CLEIA became conspicuously apparent. Moreover, in the presence of MP, the catalytic activity of labeled enzyme was kept to high extent and the stability of immunoreagents was satisfied. Finally, 59 human serum samples were detected by the MP-CLEIA and a good correlation was obtained when comparing the results with that from a commercial electrochemiluminescence immunoassay kit. [Copyright &y& Elsevier]

Abstract: The chemical nature of a nanoparticle surface determines its bioactivity and toxicity in vivo. Rational surface-chemistry modifications play a key role in modulating the toxicity of nanoparticles and applying nanotechnology to life sciences and medicine. However, there is a bottleneck in characterizing the organic molecules attached to the nanoparticle surface after such modifications. This review summarizes recent developments in analysis of surface chemistry of nanomaterials using various proton nuclear magnetic resonance spectroscopy (1H NMR) techniques. While these developments have had a substantial impact on nanoparticle-surface chemistry, more quantitative, flexible, and practical analytical techniques and strategies have still to be developed. [Copyright &y& Elsevier]

Direct measurement of time-resolved fluorescence from a washed surface of an immunoassay well constitutes an advantage compared with label development options involving signal generation in solution. Epi-fluorometric detection collects the signal from only a small part of the microtiter well’s bottom surface and it is inadequate for the optimal assay sensitivity when using binding surfaces introduced by large coating volume. This study reports on the use of streptavidin-coated spots intended to condense the binding of the labeled antibodies to coincide with the excitation beam. The spots were generated in special microtiter wells containing 2.5-mm, 3.5-mm, and 4.5-mm diameter indentations by adsorption from liquid droplets containing either native (SAv) or modified high-capacity (GA-SAv) streptavidin. The SAv-coated and GA-SAv-coated spots exhibited maximum Eu–biotin binding densities of 0.080 and 0.47 pmol/mm2, respectively. A sandwich-type immunoassay of thyroid-stimulating hormone (TSH) provided a fivefold to sixfold increase in the signal-to-background ratios of the spot assay and an equivalent improvement in the detection limit (DL < 0.01 mU/L) compared with a reference assay. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

This work describes a procedure for the separation–preconcentration of Fe(III), Pb(II) and Cr(III) from some water samples using a column-filled Amberlite XAD-2000 resin. The analyte ions retained on the column were eluted with 0.5molL−1 HNO3. The analytes in the effluent were determined by atomic absorption spectrometry. Several parameters governing the efficiency of the method were evaluated including pH, resin amount, sample volume, flow rates, eluent type and divers ion effects. The recoveries under the optimum working conditions were found to be as 100±1% Fe, 96±1% Pb and 93±2% Cr. The relative standard deviations and errors were less than 2% and 5%, respectively. The detection limit based on three standard deviations of the blank was found to be 0.32, 0.51 and 0.81μgL−1, for Fe, Pb and Cr, respectively. The procedure was applied to the determination of Fe, Cr and Pb in hot spring water and drinking water samples. [Copyright &y& Elsevier]

Abstract: The need for self-protecting polymer or alloy implants resistant to a broad spectrum of bacterial challenges led us to investigate covalent bonding of minocycline (MIN), a tetracycline derivative, to polystyrene beads and to titanium alloy foils by oligoethylene glycol spacers. 9-Hydrazino-acetyl-amido-MIN, and simpler glycylcycline derivatives, retained minimum inhibitory concentration (MIC) against Staphylococcus aureus comparable to MIN. However, PEG-glycyl-amido-MIN showed very low activity. Hence, we coupled 9-hydrazino-acetyl-amido-MIN to the aldehyde termini of oligoethylene glycol spacers bonded to polystyrene and titanium alloy surfaces to form acid-releasable hydrazone linkages. 9-Hydrazino-acetyl-amido-MIN was released from the monolayers more rapidly at pH 5.0 than at pH 7.4. [Copyright &y& Elsevier]

Synthesis of a monoester of symmetrical diphenolic compound curcumin (1,7-bis(4-hydroxy-3-methoxy phenyl)-1,6-heptadiene-3,5-dione) with glycine has been carried out by anchoring one of its free phenolic groups to an insoluble polymeric solid-support resin controlled pore glass-long chain alkylamine (CPG-LCAA) via a 2-carbon linker by solid-phase synthesis. The other free phenolic was esterified selectively with N-protected glycinoyl chloride to give the monoester exclusively. Subsequent deprotection of the amino group and deblocking of the monoester from polymer support by treatment with hydriodic acid (HI) gave the desired product. We earlier reported synthesis of a large number of diesters of curcumin, but selective esterification of one phenolic has been accomplished by this novel method, which can be used for preparing monoesters of any symmetric diphenol in quantitative yields. [ABSTRACT FROM AUTHOR]

The synthesis and modification of 2'-deoxyuridine has been realized under Suzuki-Miyaura palladium-catalyzed cross-coupling conditions. Using Pd(PPh3)4 and Na2CO3, 5-iodo-2'-deoxyuridine bound to solid support is coupled with various boronic acids to give 5-(hetero)aryl-2'-deoxyuridine. Pd(PPh3)4 palladium catalyzed was found to be superior to Pd(OAc)2 and (NHC)Pd(allyl)Cl for Suzuki-Miyaura palladium-catalyzed reactions. [ABSTRACT FROM AUTHOR]

We have developed an efficient and inexpensive method of reverse transfection from the solid phase to suppress genes with siRNA. The method enabled the realization of (i) a high efficiency of transfection; (ii) transfection of various types of cell; (iii) a high efficiency of gene knockdown by siRNA; (iv) a low toxicity to cells; and (v) a long-term stabilization (more than 210 d) of attached transfection mixture including siRNA in multiple wells. Although array-based reverse transfection has advantages in terms of miniaturization, the method has the advantage of enabling the inclusion of various soluble factors, such as humoral factors, drugs and ligands that affect gene expression, because the liquid phase is partitioned within the individual wells of each microtiter plate. Our method of reverse transfection with siRNA in multiple wells is a powerful and high-throughput tool for the analysis of signaling pathways. [Copyright &y& Elsevier]

Abstract: Gellan gum beads are presented as a novel substrate for protein immobilization and immobilized protein activity measurements. The optical transparency of the gellan beads down to 200nm provides a method for direct quantitation of the amount of protein immobilized onto the beads. The ability to utilize these beads in a non-aqueous activation step allowed for a fourfold increase in the amount of protein immobilized, and this method was used to immobilize Protein A onto gellan beads at a final yield of 1.42±0.07mg of Protein A/g of beads. The optical transparency also allowed for detection of the activity of the immobilized Protein A simply by measuring the absorbance of the beads following capture of rabbit IgG. This activity measurement method was compared with a traditional method utilizing the amount of protein remaining in solution after the IgG capture step. The traditional method yielded an activity measurement of 10.9±0.2mg IgG/mg of Protein A, while the absorbance method showed an activity of only 7.5±0.3mg IgG/mg of Protein A. The difference can be explained by the more direct measurement used in the absorbance method. The optical transparency of the beads was also evaluated in a fluorescence based IgG capture experiment, showing that detection of fluorescent IgG captured on the beads was possible with no interference from the beads. [Copyright &y& Elsevier]

Abstract: Polymorph screening of a model compound (nitrofurantoin) was performed. Nitrofurantoin was crystallized from acetone–water mixtures with varying process parameters. Two anhydrate forms (α and β) and one monohydrate form (II) were crystallized in the polymorph screen. The solid forms were analyzed with three complementary spectroscopic techniques: near-infrared (NIR) spectroscopy, Raman spectroscopy and terahertz pulsed spectroscopy (TPS), and the results of the solid phase analysis were verified with X-ray powder diffraction (XRPD). NIR and Raman spectroscopy were coupled to achieve a rapid and comprehensive method of solid phase analysis. The hyphenated NIR/Raman spectroscopic data were analyzed with a multivariate method, principal component analysis (PCA). The combination was found effective in screening solid forms due to the complementary characteristics of the methods. NIR spectroscopy is powerful in differentiating between anhydrate and hydrate forms and intermolecular features, whereas Raman spectroscopy is sensitive to intramolecular alterations in the molecular backbone. [Copyright &y& Elsevier]

Abstract: We found that the flash motion of Ga droplets induced by Joule heating transformed an amorphous carbon pillar into a multi-walled carbon nanotube through a solid phase reaction. The base material of the amorphous carbon pillar was fabricated by focused ion beam induced chemical vapor deposition (FIB-CVD), in which fine gallium droplets were consequently incorporated for use as the primary Ga ions in the FIB-CVD process, and dispersed locally in the core region of the pillar. Thus, a flush discharge into the pillar quickly heated up the Ga droplets, inducing a flash motion of Ga toward the negative electrode. The heated Ga droplets dug out a tunnel inside the pillar, simultaneously inducing a catalytic transformation into a multi-walled graphitic tube. [Copyright &y& Elsevier]

Abstract: Fluorescently labeled antibodies are very important tools in cell biology, providing for specific and quantitative detection of antigens. To date, fluorophore labeling of antibodies has been performed in solution and has been limited by low-throughput methods requiring a substantial amount of pure antibody sample at a high concentration. We have developed a novel solid-phase labeling protocol for small amounts (i.e. micrograms) of antibodies with fluorescent dyes. Protein A affinity medium was used as solid support in a micropipette tip format. This solid-phase approach, including the advantage of the strong and specific interaction between Protein A and antibodies, allows for simultaneous purification, labeling and concentration of the antibody sample, making it possible to start with unpure antibody samples at low concentrations. We have optimized the protocol with regard to reaction pH, time, temperature and amount of amine reactive dye. In addition, we have evaluated the stability and activity of the labeled antibodies. To evaluate the reproducibility and robustness of this method we labeled eight antibodies with amine reactive fluorescent dyes followed by evaluation of antibody specificity on protein arrays. Interestingly, this gave an extremely high conformity in the degree of labeling, showing the robustness of the method. The solid-phase method also gave predictable and reproducible results and by varying the amount of reactive dye, the desired degree of labeling can easily be achieved. Antibodies labeled using this solid-phase method were similar in stability and activity to antibodies labeled in solution. This novel solid-phase antibody labeling method may also be applicable for other conjugation chemistries and labels, and has potential for high-throughput applications. [Copyright &y& Elsevier]

Abstract: A rapid and convenient one-pot route to solid supported benzhydrylamine linkers with high chemical loading is described. Such linkers possess differing levels of acid lability, which could be exploited in solid phase synthesis applications. They have also been utilised to prepare novel and potentially useful N-methylated derivatives. We also report an effective on-resin purification strategy for reductive amination, which is facilitated by the varying acid lability of resin-linked secondary amines or tertiary amine by-products. [Copyright &y& Elsevier]

Abstract: We report here the first method to load acidic heterocyclic compounds (1,2,4-oxadiazol-5-one, 1,2,4-oxadiazol-5-thione and 1,2,3,5-oxathiadazol-2-oxide) on a polymer. Using Mitsunobu conditions, these heterocycles were anchored on a 4-hydroxymethyl-3-methoxyphenoxybutyric acid benzhydrylamine (HMPB-BHA) resin. After diversification, compounds can be recovered by a simple treatment in diluted TFA. To illustrate the utility of this procedure, iodophenyl derivatives were anchored on the same resin. A HRMAS-NMR analysis shed light on the reactivity of these heterocycles in Mitsunobu conditions. A subsequent diversification using a Sonogashira coupling produced a small array of novel (arylethynyl)-phenyl-1,2,4-oxadiazol-5-ones. [Copyright &y& Elsevier]

Abstract: Magnetic bead-based solid phases are widely used for the separation of nucleic acids from complex mixtures. The challenge to selectively separate specific DNA molecules (via complementary hybridization) in a single step is the selection of a linker between the capture probe and the solid support that can be exposed to high temperatures in the presence of a high salt media. This article presents a general platform for the fabrication of a magnetic bead-based selective solid phase that can be used for subtractive hybridization or sequence capture applications. Phosphorus dendrimers are used for the first time as linkers in a magnetic bead-based selective solid phase for capture of genomic DNA. Aside from providing a high loading capacity, they render a stable bond between the capture probe and the surface under the high temperature and salt conditions required for denaturation and capture to proceed in a single step. The thermal stability of the solid phase under these conditions is first demonstrated by hybridizing a Cy3-labeled target. The selective capture of DNA targets in a single step is then demonstrated by subtractive hybridization of fragmented human genomic DNA. The specificity and selectivity of the solid phase are demonstrated by the recovery of adenovirus serotype 4 DNA spiked into the human DNA target. The effect of steric and electrostatic constraints was also investigated by using dendrimers of different generations that vary in their size and the number of branches. The results demonstrate that this platform can be used for single-step subtractive hybridization applications with better performance over the conventional two-step method using streptavidin-coated magnetic beads. [Copyright &y& Elsevier]

Abstract: Gastrointestinal processing and assimilation of Cu in vivo was investigated by sequential chyme analysis over a 72 h period following ingestion of a single satiation meal (3% body weight) of commercial trout food (Cu content=0.42 μmol g−1) by adult rainbow trout. Leaded glass ballotini beads incorporated into the food and detected by X-ray radiography were employed as an inert marker in order to quantify net Cu absorption or secretion in various parts of the tract. Cu concentrations in the supernatant (fluid phase) fell from about 0.06 μmol mL−1 (63 μM) in the stomach at 2 h to about 0.003 μmol mL−1 (3 μM) in the posterior intestine at 72 h. Cu concentrations in the solid phase were 10 to 30-fold higher than in the fluid phase, and increased about 4-fold from the stomach at 2 h to the posterior intestine at 72 h. By reference to the inert marker, overall net Cu absorption from the ingested food by 72 h was about 50%. The mid-intestine, and posterior intestine emerged as important sites of net Cu and water absorption and a potential role for the stomach in this process was also indicated. The anterior intestine was a site of large net Cu addition to the chyme, probably due to large net additions of Cu-containing fluids in the form of bile and other secretions in this segment. The results provide valuable information about sites of Cu absorption and realistic concentrations of Cu in chyme fluid for future in vitro mechanistic studies on Cu transport in the trout gastrointestinal tract. [Copyright &y& Elsevier]

Abstract: The use of a periodic acid/alumina system for the iodination of activated aromatics and 1,3-dicarbonyl compounds is described. [Copyright &y& Elsevier]

Microarray technology provides an opportunity to monitor multiple parameters simultaneously. High-throughput applications such as blood donation screening could greatly benefit from performing various tests on a single testing platform. Blood grouping represents one part of the donation testing complementing the screening for blood-borne pathogens. Blood group serology traditionally exploited agglutination as the detection method. In this investigation, we have adapted blood grouping reactions to a solid-phase microarray substrate in a non-agglutination reaction format as an initial step in the development of a combined microarray testing platform. We have investigated immobilization of proprietary antibodies on multiple surfaces and monitored their performance under various reaction conditions. For the first time, highly specific blood grouping has been achieved on a planar microarray using directly labelled erythrocytes or a secondary labelled reagent using fluorescent signal end point readout. We have also complemented microarray data with a label-free, surface plasmon resonance-based Biacore platform data and used the real time quantitative measurement to rank anti-A antibodies according to the strength of reaction with the immobilized synthetic blood group antigen A. [ABSTRACT FROM AUTHOR]

Abstract: Dimethyl sulfoxide (DMSO) was simply immobilized to neutral alumina via quite strong hydrogen bonding between sulfoxide oxygen and surface alumina hydroxo groups. The produced alumina-modified dimethyl sulfoxide (AMDMSO) solid phase (SP)-extractor experienced high thermal and medium stability. Moreover, the small and compact size of DMSO moiety permit high surface coverage evaluated to be 2.1±0.1mmolg−1 of alumina. Hg(II) uptake was 1.90mmolg−1(distribution coefficient log K d =5.658) at pH 1.0 or 2.0, 1.68mmolg−1 (log K d =4.067) at pH 3.0 or 4.0 while the metal ions Ca(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II) showed low values 0.513–0.118mmolg−1 (log K d <3.0) in the pH range 4.0–7.0. A mechanism was suggested to explain the unique uptake of Hg(II) ions by binding as neutral and chloroanionic species predominate at pH values≤3.0 of a medium rich in chloride ions. A direct and fast batch separation mode was achieved successfully to retain selectively Hg(II) in presence of other eight coexisting metal ions. Thus, Hg(II) was completely retained; Ca(II), Co(II), Ni(II) and Cd(II) were not retained, while Pb(II), Cu(II), Zn(II) and Fe(III) exhibited very low percentage retention evaluated to be 0.42, 0.49, 1.4 and 5.43%, respectively. The utility of the new modified alumina sorbent for concentrating of ultratrace amounts of Hg(II) was performed by percolating 2l of doubly distilled water, drinking tap water, and Nile river water spiked with 10ng/l over 100mg of the sorbent packed in a minicolumn used as a thin layer enrichment bed prior to the determination by CV-AAS. The high recovery values obtained (98.5±0.5, 98.5±0.5 and 103.0±1.0) based on excellent enrichment factor 1000, along with a good precision (R.S.D.% 0.51–0.97%, N =3) demonstrate the accuracy and validity of the new modified alumina sorbent for preconcentrating ultratrace amounts of Hg(II) with no matrix interference. [Copyright &y& Elsevier]

Ecotoxicological screening of dust sampled throughout a Kenyan tannery was conducted using a luminescence ( lux )-based bacterial biosensor for both solid and liquid assays. This was complemented by chemical analysis in an attempt to identify possible causative toxic components. The biosensor results showed a highly significant ( p 3 for total Cr (highest Cr concentration was at chemical handling at 209.24 mg l -1 ) in all dust samples. The weighing area had the highest Ni concentration (1.87 mg l -1 ) and the chemical handling area showed the highest Zn concentration (31.9 mg l -1 ). These results raise environmental health concerns, as occupational exposure to dust samples from this site has been shown to give rise to elevated concentrations (above the stipulated levels) of chromium in blood, urine and some body tissues, with inhalation being the main route. Health and Safety Executive (HSE), UK, and American Conference of Governmental Industrial Hygienist (ACGIH) and National Institute for Occupational Safety and Health (NIOSH), USA stipulates an occupational exposure limit of 0.5 mg Cr/m 3 (8 h TWA) for total chromium. However, schedule 1 of Controls of substances hazardous to health (COSHH) regulations developed by HSE, indicate 0.05 mg m 3 (8 h TWA reference periods) to be the limit for Cr (VI) exposure. The exposure limit for individual (e.g., Cr, Zn, Ni etc.) contaminants (homogeneity) was not exceeded, but potential impact of heterogeneity (multi-element synergistic effect) on toxicity requires application of the precautionary principle. [ABSTRACT FROM AUTHOR]

Abstract: Peptidotriazoles, unnatural oligomers with alternating amide and triazole linkages, are synthesized efficiently on solid support. The key transformations involve multiple cycles of 1,2,3-triazole formation, using soluble Cu(I) catalyst and conditions that do not generate precipitate on solid support nor require exclusion of oxygen. Our synthetic protocol will enable the preparation of other unnatural oligomers with multiple triazoles using solid phase methodologies. [Copyright &y& Elsevier]

Abstract: Streptavidin (SAv)-coated 96-well microtitration plates from commercial suppliers (six plates) and our laboratory (two plates) were tested with respect to their binding capacity for small and large molecules, leaching, well-to-well variation and immunoassay performance. The binding capacities for europium-labelled biotin (Eu-biotin) varied from 4.4 to above 150 pmol/well depending on the plate, and for biotinylated monoclonal antibody from 1.2 to 6.4 pmol/well (190–1030 ng). Incubation for 1 h in regular immunoassay buffer resulted in leaching of 0.6–76 ng of SAv from unwashed wells and 0.5–60 ng from pre-washed wells. The desorbed quantity represented up to 3.4% of the maximal Eu-biotin binding capacity. Coating-related variation of 96 wells (CV% values) ranged from 1.2% to 8.0% when tested with respect to maximum binding capacity. Immunofluorometric assay for TSH as well as enzyme immunoassays for CA125 and PSA revealed immunoassay-related performance of the plates, regarding signal levels, variation and non-specific binding characteristics. Non-specific binding and variation tended to increase in the highest capacity plates, whereas some low capacity plates fulfilled the assay requirements optimally. Good performance with respect to capacity, coating homogeneity or leaching was not by definition reflected in the performance of two-site heterogeneous immunoassays. [Copyright &y& Elsevier]

Solid‐phase phosphorescence (SPP) has become an established approach for the trace analysis of organic compounds. More recently, SPP has been successfully applied to the trace analysis for inorganic species. In this mini review, initially a brief overview of SPP is given. Then the important aspects related to adsorption of the phosphors on the solid phase are discussed. In addition, the basic photophysical aspects of phosphorescence are presented. The physicochemical interactions in SPP, such as the rigidity of the solid phase, effects of oxygen and moisture, heavy‐atom salts, and temperature, are considered. Finally, several recent applications of SPP to both organic and inorganic compounds are discussed. [ABSTRACT FROM AUTHOR]

Abstract: A solid-phase synthetic route to quinoxaline, thiazine, and oxazine analogs is described. N-Alloc-3-amino-3-(2,4-difluoro-5-nitrophenyl)propanoic acid was tethered to Rink resin via its carboxylic acid group. The 4-arylfluorine was displaced with a primary amine, alcohol, or thiol to create, respectively, a resin bound aniline, phenol, or thiophenol derivative with one diversity element and one single atom (e.g., N, S, or O) diversity point. A fused heterocyclic system was subsequently created via a benzyne heterocyclization initiated by dehydrofluorination with strong base. Acid treatment released the desired products in high yield and moderate purity. [Copyright &y& Elsevier]

A new sensor based on oxalic acid esters (bis(2,4,6-trichlorophenyl) oxalate-TCPO and bis(2,4-dinitrophenyl) oxalate-DNPO) is presented in this work. The sensor is used for determination of hydrogen peroxide in different samples. Influence of different substances as possible interferences for the determination of new sensor was tested. Water is the biggest interfering substance but it was proved that it does not interfere with determination when it is present in traces. Different organic substances showed influence in different concentration ranges for two esters. Because of this it was possible to choose the system for different determinations depending on the sample matrix. Due to influence of water on esters, the new method was tested on the samples that contain water in traces. Since the samples were washing powders that contained sodium perborate and percarbonate, it was necessary to make calibration curves for both esters. In all cases the calibration curve was linear for concentrations of 1000&ThickSpace;µg&ThickSpace;L -1 . The detection limit for the TCPO ester and in the case of sodium perborate was 86&ThickSpace;µg&ThickSpace;L -1 and for the DNPO ester is 48&ThickSpace;µg&ThickSpace;L -1 . The lowest concentrations that could be measured were 100&ThickSpace;µg&ThickSpace;L -1 in both cases. Detection limits in the case of sodium percarbonate were 54&ThickSpace;µg&ThickSpace;L -1 (for TCPO) and 48&ThickSpace;µg&ThickSpace;L -1 (for DNPO). The lowest concentrations that could be measured in both cases was 100&ThickSpace;µg&ThickSpace;L -1 . The results obtained with the new sensor were compared with results obtained with the standard iodometric method for determination of hydrogen peroxide in per-salts. The results showed that new sensors could be applied successfully for the determination of hydrogen peroxide in the bleaching component of washing powder. [ABSTRACT FROM AUTHOR]

The synthesis of pyrazolo[4,3-d]pyrimidine nucleoside library using solid-phase parallel synthesis methodology is described. Glycosylation of the trimethylsilyl (TMS) derivative of 1- and 2-(methyl)-1H and 2H-pyrazolo[4,3-d]pyrimidine-5,7-(4H,6H)-dione (5) with 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose in the presence of TMS triflate provided two novel protected nucleosides 6 and 7. The structures of 6 and 7 were assigned by 1H and 2D NMR experiments. Nucleosides 6 and 7 were then transformed to the key intermediates 12 and 15 respectively. Reaction of 12 and 15 with MMTCl resin in the presence of 2,6-lutidine afforded the necessary scaffolds B and C. Different amines (96) were introduced selectively by nucleophilic substitution on scaffolds B and C using solid-phase parallel semi-automated synthesizer. Cleavage of the products from the solid support with 30% HFIP in a parallel fashion yielded nucleoside libraries simultaneously, and they were analyzed and characterized by high-throughput LC-MS. [ABSTRACT FROM AUTHOR]

Abstract: In this letter, we describe the iterative solution phase synthesis of a triarylamine trimer as proof of concept towards the synthesis of oligomeric materials by solid-phase synthesis. Our model system utilises the stability of germanium linkers to nucleophilic conditions to develop efficient steps towards oligomer synthesis via (i) selective deprotection of tert-butyl-dimethyl-silyl ether (OTBDMS) functionality, (ii) conversion to reactive trifluoromethanesulfonate (triflate) functionality and (iii) Suzuki cross-coupling reactions. [Copyright &y& Elsevier]

Abstract: The attachment of two aniline-based chromophores, Disperse Black 3 and Pararosaniline, to beaded controlled pore glass (CPG) and their testing as fibre optic based pH sensors is described. Synthetic methods for their attachment at specified loadings to CPG were developed. The Disperse Black 3 sensor displayed a rapid response time and a dynamic range between pH1.0 and 2.5, while the Pararosaniline-bearing sensor gave an extremely slow response time but a large sensing range from pH1 to 11. [Copyright &y& Elsevier]

Abstract: A solid-phase vibrational spectrometry-based methodology (solid-phase Fourier transform-Raman spectrometry, SP-FT-Raman) has been developed for caffeine determination in commercial energy drink samples. The Raman spectra of caffeine, fixed on a C18 solid phase packed into a glass tube of 5mm i.d., was obtained directly between 3500 and 70cm−1. In order to quantify caffeine, Raman intensity between 573 and 542cm−1 corrected using a baseline defined between 580 and 540cm−1 was used. A repeatability of 3%, as relative standard deviation of five analysis of a 200mgl−1 concentration, and a limit of detection of 18mgl−1 were obtained. The SP-FT-Raman procedure provides a sampling frequency of 13.3h−1, higher than that of liquid chromatography (LC), which was 7.0h−1. The use of FT-Raman reduces the reagent consumption and waste generation, also minimizing the sample handling. Results obtained by the developed procedure were statistically comparable with those found by a reference LC method. [Copyright &y& Elsevier]

Ligand displacement immunoassay (LDI) is an immunoassay that uses an immunocomplex consisting of immobilized antibodies that have been presaturated with labeled analyte ligand, or conversely, it can use a complex of immobilized analyte ligands that are prebound with corresponding labeled antibodies. The complex of antibody-antigens dissociates when it is exposed to analytes. Thus, the labeled reagents are displaced by the analyte in the test sample. This review focuses on three aspects of immunochemistry that are germane to the development of an LDI. The interaction of antibody with antigen, the solid phase and methods used for the immobilization of immuno-reagents and the labels and labeling methods used in LDI are discussed in details. [ABSTRACT FROM AUTHOR]

Abstract: Two chemiluminescence enzyme-linked immunosorbent assay (ELISA) methods based on avidin–biotin system and Fluorescein-iso-thiocyanate (FITC)-anti-FITC system as two different solid phase for the determination of albumin in urine were optimized, characterized and compared. Avidin or anti-FITC antibody was coated in the microplates to provide a universal solid phase which improved the variability and sensitivity. Alkaline phosphatase (ALP) labeled albumin and albumin from standard or patient samples compete for biotinylated-antibody or FITC labeled antibody binding sites. Enzyme activity in the bound fraction was detected with the chemiluminescence substrate 4-methoxy-4-(3-phosphatephenyl)-spiro-(1,2-dioxetane-3,2′-adamantane) (AMPPD). The influence of several physico-chemical parameters, such as incubation time, detergent concentration and solid phase conditions were also studied. For the two solid phase, both the linear range and the limit of detection of albumin were 0.15–15 and 0.089μg/mL, compared with the commercially ELISA kit, a good correlation were obtained. Moreover, three different solid phases include avidin–biotin system, FITC–anti-FITC system and the anti-albumin Ab directly coated the microtitre plates were compared mainly from the cost and precision, the results showed: (1) when the avidin–biotin system as solid phase, the amounts of the antibody used was only the 1/10 than those of the anti-FITC antibody as solid phase and antibody directly coated the microtiter plates; (2) the C.V. of these two solid-phase CL ELISA methods were lower than that of antibody directly coated solid phase. [Copyright &y& Elsevier]

Abstract: This paper covers efforts to discover orally active potent and selective oxytocin antagonists. Screening pooled libraries identified a novel series of 2,5-diketopiperazine derivatives with antagonist activity at the human oxytocin receptor. We report the initial structure–activity relationship investigations and the determination of the stereochemistry of the most potent compounds. [Copyright &y& Elsevier]

In solid-phase analytical techniques, a reduction in nonspecific binding at the solid-phase surface is key to obtaining excellent assay performance. We have developed a new preparation method to minimize nonspecific protein binding in the solid phase. Microwave irradiation (2.45 GHz, 500 W) was used to produce a highly protein- resistant, dense coating layer of bovine serum albumin (BSA) that was acid-denatured at pH 4.0. The protein resistance in the BSA-coated magnetic bead was assessed by measuring the enzyme activity of alkaline phosphatase-labeled mouse immunoglobulin G (ALP-IgG) that nonspecifically bound to the surface. In addition, we observed the BSA-coated beads by atomic force microscopy (AFM) and also quantitatively measured the bound BSA, enabling us to propose a model for the denaturation processes caused by microwave irradiation. Compared to conventional BSA-coated beads prepared at pH 8.0 without microwave treatment, the activity of nonspecifically bound ALP-IgG was markedly reduced to 3%. Our results strongly suggest that a meshwork film of extensively associated BSA molecules is formed on the bead surface. This new technique should be useful for the development of polymer supports for use in solid-phase separation analyses, such as heterogeneous immunosorbent assay and column chromatography. [ABSTRACT FROM AUTHOR]

A mechanism of phase-transfer catalysis in a solid/liquid system was proposed during akinetic investigation of the aminolysis of 4-nitrophenyl acetate with solid potassium glycinate in chlorobenzene in the presence of 18-crown-6. The quantitative parameters were determined for all the stages of the catalytic cycle, including the distribution of the reagents between the phases and the chemical reactions that occur. [ABSTRACT FROM AUTHOR]

Streptavidin-coated microtitration plates have an important role as a solid phase in clinical diagnostics. We have designed techniques for evaluating quantitative and functional aspects of streptavidin adsorbed in microtitration wells. The theoretical monolayer adsorption capacity was modeled based on the molecular dimensions of the protein. Adsorbed streptavidin was quantified by direct labeling of protein with terbium chelate and with a sensitive bicinchoninic acid-based protein assay. A new small molecular weight (1037 Da) reporter molecule, a europium-labeled biotin (Eu-biotin), was synthesized and used for monitoring adsorption and for determination of biotin-binding capacities of the streptavidin-coated wells. The theoretical monolayer adsorption of streptavidin yielded 6.20 pmol/cm2 (370 ng) and consequently the theoretical adsorption capacity of a C12-format microtitration well (200 μl liquid, coated area 1.54 cm2) was 9.55 pmol/well (570 ng). Adsorption properties of streptavidin from two suppliers were tested, one of which yielded 350–380 ng/well while the other yielded over 500 ng/well. The biotin binding capacities were about 11 and 14 pmol/well, respectively. We managed to quantify surface-adsorbed streptavidin with sensitive fluorescence and protein measurement methods in the microtitration well. The new Eu-biotin reporter molecule enabled an exact and convenient determination of the biotin-binding capacities of streptavidin surfaces. [Copyright &y& Elsevier]

Coumarin and its derivatives occur widely in nature. Many attempts were made for synthesis of various coumarin derivatives because of their interesting biological activities. In this study, solid phase synthetic approach of 3-(4-hydroxyphenyl)coumarin was achieved for combinatorial synthesis of substituted 3-phenylcoumarin analogues. Starting from 4-hydroxyphenylacetic acid methyl ester, release of 3-(4-hydroxypnehyl)coumarin from polymer support was accomplished. [ABSTRACT FROM AUTHOR]

A small library of kojic acid-tripeptides (Ko-X1X2X3) was prepared by solid-phase parallel synthesis and assayed to evaluate their tyrosinase inhibitory activity. Most of the kojic acid-tripeptides showed better activities than kojic acid. Kojic acid-FWY was the best compound, and it exhibited 100-fold tyrosinase inhibitory activity compared with kojic acid. In addition, their storage stabilities were approximately 15 times higher and their toxicity was lower than that of kojic acid. [Copyright &y& Elsevier]

A linear pixel-array detector was employed to create spatially resolved multi-layered IR-images of a large collection of polymer beads supporting carbonyl and nitrile monomers. The feasibility of creating multi-layered IR-images with nitrile IR-band separation of 4 cm-1 was demonstrated, an important issue when considering that many monomers used to develop combinatorial libraries are structurally analogous and therefore occupy very similar positions in the IR-spectrum. Strategies for obtaining high quality spectral data from both imaging and mapping IR-microscopes without compromising on sample area, analysis time, or spatial resolution are also described. [ABSTRACT FROM AUTHOR]

The first example of a dynamic kinetic resolution (DKR) using immobilized amine nucleophiles is described. This approach utilizes a nucleophilic amine attached to a solid phase resin via an organic spacer. The optical purities of the N-substituted α-amino ester products are superior to the solution phase DKR with diastereomeric ratios ranging from 11:1 to 18:1 and chemical yields between 66% and 98%. [Copyright &y& Elsevier]

The development of a flow-through solid-phase room temperature phosphorescence (RTP) method for the sensitive determination of orthophosphate in aqueous samples, based on the energy transfer from a phosphor molecule (acting as a donor) to an orthophosphate dye-indicator (acting as an acceptor) is described.The proposed method, to our knowledge the first RTP optosensor for orthophosphate developed so far, is based on the injection in a flow system of 1 ml sample treated to form phosphomolybdenum blue from the orthophosphate. After injection, the phosphomolybdenum blue is on-line co-immobilised onto a polymeric resin containing adsorbed erythrosine B. This selected donor molecule exhibits strong RTP in a de-oxygenated aqueous media when retained on the surface of polymeric resin beads. Absorption spectra of the phosphomolybdenum blue possess a desirable spectral overlap with the emission spectra of the RTP donor and a non-radiative energy transfer occurs from the phosphor molecule to the acceptor dye. An increase in the concentration of orthophosphate of the solution causes an absorption increase of the acceptor (phosphomolybdenum blue) and, therefore, an increase in the energy transfer, which brings about a decrease of the RTP emission. After measurement, the active sensing phase can be regenerated by passing 2 ml of 2 M sodium hydroxide plus 2 ml of methanol. After the injection of 1 ml of 2×10−6 M erythrosine B the system is prepared again for a new sample injection.Potential interferences by ions present in natural waters, which could affect the optosensor response, and analytical performance characteristics of the RTP method are discussed in detail. An orthophosphate detection limit of 0.5 ng ml−1 (for 1 ml sample injection volume) was achieved. Finally, the selected RTP flow-through optical sensor has been successfully tested for the determination of orthophosphate in different water samples at a very few ng ml−1 levels. [Copyright &y& Elsevier]

We describe the synthesis of a series of low molecular weight inhibitors of the αvβ3 integrin obtained by modifying a high-throughput screening hit with micromolar activity. A solid phase synthesis to prepare 3-phenylthio-3-nicotinyl propionic acid derivatives, exemplified by 13c, was set up. Compounds with nanomolar activity in the biochemical assay and able to efficiently inhibit cell adhesion mediated by vitronectin have been obtained. [Copyright &y& Elsevier]

The performance of remedial treatments is typically evaluated by measuring the concentration of specific chemicals. By adding toxicity bioassays to treatment evaluations, a fuller understanding of treatment performance is obtained. The solid phase Microtox® assay is a useful tool in characterizing the toxicity of contaminated soils and sediments. This study compares the performance of the solid phase and saline extract Microtox assays in two experiments using two soils contaminated with polycyclic aromatic hydrocarbons (PAHs). The first experiment, conducted to refine the solid phase assay procedures, evaluated sample holding times, sample replication, and reference toxicant controls. The effective concentration reducing light emission by 50% (EC50) of four samples was measured with eight replicates of each sample. Samples were stored for as long as two weeks without showing substantial changes in toxicity. For future studies, three replicates of each sample are recommended because that degree of replication yielded a statistical power of more than 95% in most samples. Phenol was a reliable reference toxicant with a mean EC50 of 21.76 and a 95% confidence interval of 15.6 to 27.9 mg/L. In a second experiment, the solid phase Microtox assay was compared to saline extract Microtox assays with mixing times ranging from 5 min to 16 h. The solid phase assay was more sensitive yielding EC50s 7 to 50 times lower than the extract EC50s. In addition, the saline extract assays displayed results that varied for mixing times of less than 2 h. Based on these two experiments, the solid phase Microtox test has proved to be a useful assay for measuring the toxicity of PAH-contaminated soils. [ABSTRACT FROM AUTHOR]

Solid-phase PAMAM dendrimer was synthesized by the repetitive addition of a branching unit to silica gel. All synthesis steps were monitored by infrared spectroscopy to investigate the reaction rate. Based on the measurements of infrared spectra, which showed the ester group varied as a function of reaction time, a reaction kinetics model was proposed and simulated. FT-IR and TGA measurements suggested that a ‘cross-linking’ reaction occurred in amidation process and generated structural defects, which decreased the grafted amount of dendrimer on silica gel. In addition, the analysis of reaction rate constants indicated that due to the formation of an intermediate, Michael addition of methyl acrylate to diamine was probably hindered by steric crowding. [ABSTRACT FROM AUTHOR]