bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrophoresis of proteins across a transverse sodium dodecyl sulfate gradient
Authors: Gianazza Elisabetta , Vignati Mara , Santi Ombretta , Vecchio Giuseppe
Published: May 2005

We describe a new protocol for denaturant gradient gel electrophoresis, namely the migration of proteins across transverse sodium dodecyl sulfate (SDS)‐gradients. We show how such gradients may be reproducibly cast, and demonstrate their stability with time once an appropriate SDS reservoir is arranged at the cathode. SDS affects both size and surface charge of the molecules, and influences the secondary and tertiary structure to a variable extent, even in opposite directions. Hence, distinct, sometimes complex, denaturation patterns may be observed for different proteins.
Rat urinary proteins binding human IgE detected by chemiluminescence
Authors: Bayard Cecilia , Vesterberg Olof
Published: May 2005

Work with laboratory animals involves the increased risk of developing an allergy. Certain proteins in male rat urine have been shown to be major allergens, i.e., Rat n 1.01 and Rat n 1.02. Rat urinary proteins separated by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) were electroblotted to polyvinylidene difluoride (PVDF) membranes. Immunoblot analysis of human IgE binding components in rat urine utilizing chemiluminescence and a newly developed luminometer is described. Luminometer scanning curves of IgE reactivity to the separated rat urinary proteins are demonstrated. Rat allergic individuals showed different immune responses to the separated proteins. Rat n 1.02, also known as the major protein α2u‐globulin, was not always the dominant allergen. Another protein in the albumin region, 60–67 kDa, was found to be an important allergen to some rat‐sensitive subjects. Reactivity in the skin prick test with purified Rat n 1.01 and Rat n 1.02 fractions were strong. However, in dot blot under nondenaturing conditions, only weak responses were obtained to the purified rat urinary proteins except for the albumin fraction. Chemiluminescence measurements in blotting membranes of patient IgE bound to different dilutions of certain rat urine proteins revealed good quantitative relationships. Three different chemiluminescence substrates were tested. Measurement of IgE bound to individual allergens as well as the abundance and relative importance of various allergens were studied.
Use of a Hepta‐tyr glycopeptide antibiotic as chiral selector in capillary electrophoresis
Authors: Fanali Salvatore , Aturki Zeineb , Desiderio Claudia , Boss Alessandra , Righetti Pier Giorgio
Published: May 2005

A new glycopeptide antibiotic, MDL 63,246 (Hepta‐tyr), of the teicoplanin family, has been evaluated in capillary electrophoresis for the resolution of chiral compounds of pharmaceutical and environmental interest. Electrophoretic separations were carried out in a polyacrylamide‐coated capillary using the partial filling‐counter current mode with aqueous‐organic buffers in the pH range 4–6. Experimental parameters affecting resolution, such as antibiotic concentration, buffer pH, organic modifier type and capillary temperature, were studied. The Hepta‐tyr antibiotic exhibited a high enantiorecognition capability towards the studied compounds at very low concentrations (1–2 mg/mL). The optimum experimental conditions were achieved by using a buffer at pH 5 containing acetonitrile at 25°C.
Clinical analysis of human urinary proteins using high resolution electrophoretic methods
Authors: Marshall Thomas , Williams Katherine M.
Published: May 2005

The application of isoelectric focusing (IEF), sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE), two‐dimensional electrophoresis (2‐DE) and capillary electrophoresis (CE) for high resolution electrophoretic analysis of human urinary proteins is reviewed. In each case, the information is tabulated chronologically with details of sample preparation, electrophoretic system, detection method and clinical application. The text includes an historical perspective of the use of each method for urinalysis and a detailed review of the application of the methods to the investigation of renal disease, renal transplantation, Bence Jones proteinuria (BJP), diabetes mellitus, cadmium toxicity, nephrolithiasis and cancers of the urogenital tract.
Proteomic analysis of enamel cells from developing rat teeth: Big returns from a small tissue
Authors: Hubbard Michael J.
Published: May 2005

Poor understanding of the molecular links between disturbed calcium regulation in cells and disease remains a problem of considerable biomedical importance. Dental enamel cells might provide useful insights to this problem since they handle calcium in bulk without suffering its cytotoxic effects. Two practical challenges hindered investigation of calcium handling mechanisms in enamel cells ‐ paucity of molecular information and limited availability of sample from developing rat teeth, the experimental system of choice. This paper outlines the microscale proteomic approaches we applied to overcome these difficulties and reviews several major findings that ensued from initial characterization of the enamel cell proteome. Enamel cells are now established as a powerful model for fundamental calcium research and have provided outcomes of broad biological relevance, including the discovery of a new endoplasmic reticulum protein. Future proteomic approaches that might benefit understanding of function are discussed.
Separation of neutral compounds by capillary electrokinetic chromatography using polyethyleneimine as replaceable cationic pseudostationary phase
Authors: Maichel Beate , Potocek Blahoslav , Kenndler Ernst , Gas Bohuslav , Chiari Marcella
Published: May 2005

Polyethyleneimine (PEI, molecular weight 6 × 105 − 1 × 106) is applied as a positively charged pseudostationary phase for electrokinetic chromatography (EKC) of uncharged mono‐ and oligophenols. EKC is carried out in PEI‐coated fused‐silica capillaries (with electroosmotic flow directed towards the anode) in 2‐(N‐morpholino)ethanesulfonic acid (MES) buffer (pH 7.0,20 mM) with PEI added to the solution in concentrations up to 0.70% w/v. The pseudo‐stationary phase leads to a retardation of the solutes mainly according to the number (and the position) of the OH‐groups of the separands, and is not influenced significantly by methyl groups. For 0.70% w/v PEI solution, for instance, the relative retention, ϱ, has values between 0.33 and 0.53. For the systems with the highest resolution of the separands (0.25–0.30% PEI) 190000 plates per meter are observed. The results indicate that the separation selectivity is mainly caused by ion‐dipole interactions between the OH‐groups of the solutes and the pseudostationary phase.
Use of scavenger beads to remove excess labeling reagents from capillary zone electrophoresis samples
Authors: Mort Andrew J. , Zhan Dongfeng , Rodriguez Veronica
Published: May 2005

In many cases, samples for capillary zone electrophoresis (CZE) are derivatized with a chromophore or fluorophore to enhance their detectability. To ensure efficient labeling, a large excess of labeling agent is often used, which leads to the presence of a large peak for unreacted reagent. Here we report that excess reagent can be reacted with “scavenger beads” carrying an appropriate functional group to remove it from the sample solution. We present examples of removal of aminonaphthalene mono‐, di‐, and trisulfonic acid from mixtures in which they were used to label mono‐ or oligosaccharides by reductive amination. Aldehyde‐containing scavenger beads were made by oxidizing Sephadex G‐50 beads with sodium periodate. These were added to the labeling reaction mixtures after the reductive amination of the sugars was complete. Almost complete elimination of the peak from the labeling agent could be achieved.
Capillary electrophoresis of arsenic compounds with indirect fluorescence detection
Authors: Huang Yu‐Min , Whang Chen‐Wen
Published: May 2005

A capillary electrophoresis (CE)‐indirect fluorescence detection method for arsenic compounds is described. The five arsenic species, viz., arsenite (As(III)), arsenate (As(V)), monomethylarsonate (MMA), dimethylarsinate (DMA) and phenylarsonate (PhA), were efficiently separated by CE in 8 min with an 1.5 mM fluorescein solution at pH 9.8. Fluorescein also functioned as a background fluorophore for the indirect detection of these nonfluorescent arsenic species. Linearity (r>0.996) of more than two orders of magnitude was generally obtained. The relative standard deviation (RSD) values were in the ranges 0.4–0.7% and 2.2–8.2% for migration times and peak areas, respectively. The concentration limits of detection (CLODs) for the arsenic compounds studied were between 0.04 and 0.16 μ/mL (as arsenic). The detection sensitivity was generally dependent upon the transfer ratio (TR, defined as the number of moles of fluorescein ions displaced by one mole of analyte ions) of each arsenic species. The applicability of the method for the analysis of ground water was examined.
Factors influencing the choice of buffer in background electrolytes for indirect detection of fast anions by capillary electrophoresis
Authors: Doble Philip , Macka Miroslav , Haddad Paul R.
Published: May 2005

The suitability of relatively slow (low absolute value of mobility) coanionic buffers in background electrolytes (BGEs) for indirect photometric detection of anions by capillary electrophoresis was investigated. As a model system, 2‐(cyclohexylamino)ethanesulfonic acid (CHES) was used to buffer the indirect detection electrolyte of sodium chromate. CHES (pKa 9.55) is a zwitterionic molecule carrying a net negative charge depending on the pH (effective charge −0.5 at pH = pKa). Within its useful pH buffering range CHES acted as a competing probe coanion. System peaks were induced which had deleterious effects on the detection sensitivity of slow to medium mobility anions. The mobility of the system peak was determined by the effective mobility of CHES, both of which increased with increasing pH. The peaks of analytes that migrated near or on the system peak were distorted and lost all quantitative properties. Analytes that migrated after the system peak either were not detected or reversed their responses. Analytes that migrated well before the system peak were unaffected. Consequently, the suitability of slow coanionic buffers is limited either to (i) fast anions or, (ii) a pH range much below the pKa, where the buffering capacity is not optimal.
Chemiluminescence detection in integrated post‐separation reactors for microchip‐based capillary electrophoresis and affinity electrophoresis
Authors: Mangru Shakuntala D. , Harrison D. Jed
Published: May 2005

Chemiluminescence (CL) detection based on the horseradish peroxidase (HRP) catalyzed reaction of luminol with peroxide was investigated as a post‐separation detection scheme for microchip‐based capillary electrophoresis. An integrated injector, separator and post‐separation reactor was fabricated on planar glass wafers. The fluorescein conjugate of HRP (HRP‐F1) was used as a sample for optimization of the CL detector response. In devices etched 10 μm deep, with an aluminum mirror integrated onto the backside of the detection zone to enhance collection efficiency, the detection limit, estimated at 3 standard deviations (SD) above background noise, for 1 nL injected sample plugs was 35 nM in HRP‐F1. In devices etched 40 μm deep, 8 nL plugs gave a detection limit of 7 nM. Separation and CL detection of the products of an immunological reaction of a F(ab')2 fragment of the HRP conjugate of goat anti‐mouse immunoglobulin G (IgG) with mouse IgG was performed on‐chip. A linear calibration curve was obtained for the decrease in peak height of the HRP conjugate (53 μg/mL) with increasing mouse IgG (0–60 μg/mL). When microperoxidase was used as an internal standard, the R2 value of a linear least‐squares fit was 0.9867, and the relative errors in the slope and intercept were ± 5.8 and ± 1.3%, respectively.
Detection of isozymes of deoxyribonucleases I and II on electrophoresed gels with picogram sensitivity using SYBR green I
Authors: Iida Reiko , Tsubota Etsuko , Sawazaki Kazumi , Aoyama Masahiro , Matsuki Takasumi , Yasuda Toshihiro , Nakashima Yoshimitsu , Kishi Koichiro
Published: May 2005

A highly sensitive method for detecting deoxyribonucleases (DNases) I and II on an electrophoresed gel is described. A dried agarose film sheet containing DNA as a substrate and a buffer reagent was placed in contact with the gel surface after electrophoresis (DAFO method, Yasuda et al., Anal. Biochem. 1989, 183, 84–88). After an appropriate incubation period, the film sheet was peeled off and stained with SYBR‐Green I (SG), and then the DNase isozyme bands were detected using a fluorescence image analyzer. We could detect pg levels of the DNases (DNase I, 2 pg; DNase II, 2pg), which represents a 32‐ to 128‐fold increase in sensitivity compared with the original DAFO method using ethidium bromide (EB) as the fluorescent dye. A combination of this new detection method and isoelectric focusing electrophoresis in polyacrylamide gel allowed accurate DNase I typing from 1 μL human serum. This new technique has been named SG‐DAFO, after its original dried agarose film overlay method using EB (EB‐DAFO).
Humic acid capillary zone electrophoresis adsorption on capillary walls, separation in metal ion supplemented buffer and the fingerprints
Authors: Fetsch David , Fetsch Martin , Mendéz Eladia M. Peña , Havel Josef
Published: May 2005

Capillary zone electrophoresis (CZE) in quartz tubes is often being used for the separation and characterization of humic acids (HA). A method was found to follow adsorption (and kinetics) of humic acids on a fused‐silica capillary wall. It was shown that the adsorption of humic acids on an uncoated capillary wall is high. The effect on sorption of additives to the background electrolyte (BGE) was studied. Sorption can be eliminated by adding magnesium(II) salts (14–50 mM) to the BGE (pH 3.40) with resultant highly reproducible electropherograms as well as detailed and expressive fingerprints for HA of different origin.
Analysis of heat shock‐induced monophosphorylation of stathmin in human T lymphoblastic cell line JURKAT by two‐dimensional gel electrophoresis
Authors: Fujimoto Masanori , Nagasaka Yuji , Tanaka Tatehiko , Nakamura Kazuyuki
Published: May 2005

Two‐dimensional gel electrophoresis (2‐DE) was used to study alterations in intracellular proteins of the human T lymphoblastic cell line JURKAT by heat shock at 45°C for 30 min. The 2‐DE patterns indicated an increase in the amount of a spot of molecular weight (Mr) 18500 and isoelectric point (pI) 5.6, which was a monophosphorylated form of stathmin. Stathmin is a major substrate for a proline‐rich peptide‐specific serine protein kinase, a mitogen‐activated protein kinase, however, the enzyme was not activated by the heat shock. Further examinations of the effects of cAMP, phorbol myristate acetate, cyclosporin A, and staurosporine on phosphorylation suggest that cyclin‐dependent kinases might be responsible for the heat shock‐induced monophosphorylation of stathmin.
A survey of methodological challenges for glycosaminoglycan/proteoglycan analysis and structural characterization by capillary electrophoresis
Authors: Karamanos Nikos K. , Hjerpe Anders
Published: May 2005

Proteoglycans participate and regulate several physiological processes via their glycosaminoglycan constituents. For a deeper understanding of how they interact with extracellular ligands as well as with cell bound effector molecules, the fine chemical structures of their glycosaminoglycan chains must be elucidated. Lately developed capillary electrophoretic techniques is a powerful analytical tool for the analysis of glycosaminoglycans, combining a high resolving power with sensitive detection. In this review we describe how depolymerized and intact glycosaminoglycans/proteoglycans can be characterized by capillary electrophoresis, relating these analyses to their possible biological significance. Conditions for running these separations and the detection systems for particular applications are also summarized.
Investigation of micelles and anionic cyclodextrins as pseudostationary phases for the capillary electrophoresis separation of oligosaccharides derivatized with 2‐aminobenzamide
Authors: Tran Nguyet Thuy , Taverna Myriam , Deschamps Frantz S. , Morin Philippe , Ferrier Danielle
Published: May 2005

Oligomers of glucose and oligosaccharides released from glycoproteins were derivatized with 2‐aminobenzamide. As this fluorophore imparts no charge to the oligosaccharides, several strategies were investigated to achieve capillary electrophoresis (CE) separation of both neutral and charged derivatized glycans. Micellar electrokinetic capillary chromatography (MEKC) with the addition of anionic surfactants was evaluated as a first approach: sodium dodecyl sulfate (SDS) produced the best separation of the oligoglucose fragments, where the migration was inversely related to their degree of polymerization. To demonstrate the applicability of this method for complex carbohydrate analysis, oligosaccharide mixtures derived from ribonuclease B (RNase B) and α‐acid glycoprotein (α‐AGP) were analyzed. A satisfactory separation for the high‐mannose structures found in RNase B could be obtained, whereas charged oligosaccharides from α‐AGP were poorly resolved. Cyclodextrin‐modified CE was chosen as the second approach: the effect of the addition of sulfobutylether‐β‐cyclodextrin (SBE‐β‐CD) or sulfobutylether‐γ‐cyclodextrin (SBE‐γ‐CD) on the electrophoretic mobilities and resolution of neutral and charged oligosaccharides was then studied. Selectivity of sialylated structures could be further improved by using anionic cyclodextrins (CDs) instead of micelles. However, this latter approach failed to baseline‐resolve the different high‐mannose structures of RNase B. A successful separation of the complex mixture of oligosaccharides from α‐AGP was obtained with the addition of 4% of SBE‐γ‐CD and triethylamine (TEA) in a phosphate buffer, pH 6.7.
Isolation and characterization of β‐cyclodextrin sulfates by preparative gradient polyacrylamide gel electrophoresis, capillary electrophoresis and electrospray ionization—mass spectrometry
Authors: Hileman Ronald E. , Siegel Marshall M. , Tabei Keiko , Balagurunathan Kuberan , Linhardt Robert J.
Published: May 2005

A β‐cyclodextrin sulfate mixture has been fractionated using discontinuous gradient polyacrylamide gel electrophoresis. Semidry electrotransfer of the sample onto a positively charged nylon membrane and visualization of a portion of this membrane with Alcian blue stain showed multiple bands. The bands were cut from the remaining portion of the membrane and after washing with 8 M urea, the β‐cyclodextrin sulfate fractions were eluted with 2 M sodium chloride and dialyzed. Analysis of each fraction using high resolution analytical gradient polyacrylamide gel electrophoresis as well as capillary electrophoresis, using indirect detection, showed some of the fractions to be pure while others were mixtures. Each β‐cyclodextrin sulfate fraction was complexed with a basic synthetic peptide and analyzed by electrospray ionization mass spectrometry to define the mass of the components in each mixture and thereby to determine the purity of each sample.
Interval isotachophoresis for purification and isolation of ionogenic species
Authors: Weber Gerhard , Boček Petr
Published: May 2005

A new preparative electrophoretic method in free solution is described, consisting of three consecutive steps: (i) filling the separation chamber with a suitable electrolyte system and sample in parallel streams by laminar hydrodynamic flow, (ii) applying the voltage across the chamber with isotachophoretic separation for a definite time interval operating in the direction perpendicular to that of filling, (iii) reapplying a hydrodynamic flow (without voltage) and collecting the separated species via an array of outlets. This approach completely eliminates the main drawback of the continuous flow electrophoresis (CFE), i.e., the electrohydrodynamic distortion of zones. This method utilizes the instrumentation devised for CFE and enables the isolation of large amounts of individual sample species comparable to that of CFE, with a resolution comparable to that of capillary isotachophoresis. The precise timing of the consecutive steps in the procedure as well as the stability of the operational parameters are of key importance for reproducibility. By using cationic isotachophoresis with 3 synthetic pI markers as model sample species, the reproducibility, stability and the separation power of the newly presented method are demonstrated. The sample throughput corresponds to micromoles per hour.
Preparative application of commercial automated gel electrophoresis apparatus to subcellular‐sized particles: Sequential isolations, fractions re‐run, sodium dodecyl sulfate‐polyacrylamide gel electrophoresis analysis, yield and purity
Authors: Chen Nong , Chrambach Andreas
Published: May 2005

The analytical and preparative potential of automated gel electrophoresis apparatus with intermittent fluorescence scanning of the migration path, the HPGE‐1000 apparatus (LabIntelligence, Belmont, CA) was further developed in application to subcellular‐sized particles. Resolution between two rat liver microsome components in agarose (MetaPhor) gel electrophoresis was found to increase with decreasing agarose concentration to 0.04%. It was less, even in an agarose solution at that low concentration, than that in laterally aggregated 4% polyacrylamide gel. The three components of the microsomal preparation were sequentially isolated from 0.6 and 0.8% agarose gel electropherograms. One fraction when reelectrophoresed was found to exhibit the original mobility and did not give rise to the other components. Yields of each component were near‐quantitative after one or two electroelution steps. Based on protein content, no impurities could be detected in two of the microsome fractions; the third fraction contained 2% of nonmicrosome impurity. Sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) patterns of all three microsome fractions were indistinguishable from one another and from that of the unfractionated microsome preparation.
Comparative analysis of genus Vigna seeds using antiserum against a synthesized multiple antigenic peptide
Authors: Kajiwara Hideyuki , Tomooka Norihiko
Published: May 2005

Antiserum for 33 kDa vicilin‐like seed proteins in V. angularis was prepared using a synthesized multiple antigenic peptide (MAP). The anti‐MAP antiserum was applied to the protein analysis of all of genus Vigna, seeds which are stored in the Gene Bank at the National Institute of Agrobiological Resources, Tsukuba, Japan. The anti‐MAP antiserum specifically reacted with 33 kDa vicilin‐like proteins and weakly with 55 kDa vicilin‐like proteins of V. angularis by immunoblotting and could distinguish between these two types of vicilin‐like 7 S proteins. Anti‐MAP antiserum reacted with 33 kDa band both in wild and cultivated types of V. angularis (4 spots) and half species of V. radiata (2 spots). The N‐terminal amino acid sequence of the major immunoreacting spot in V. radiata seeds was analyzed. A partially homologous amino acid sequence with MAP was found in immunoreacted protein and the anti‐MAP antiserum was able to be applied as a probe to identify homologous amino acid sequence in other proteomes. V. radiata species could be divided by their immunoreactivities into two groups: the group from Southeast Asia and Australia, which reacted with the anti‐MAP antiserum, and the group from West Asia and Madagascar, which did not. The abundant proteins in V. mungo, seeds at 55 kDa showed strong reactivity signals with anti‐MAP antiserum. The existance of a homologous amino acid sequence with MAP was suggested in the 55 kDa proteins. The seed proteins in V. aconitifolia, V. umbellata, V. vexillata, V. marina, V. unguiculata, and V. oblongifolia did not show any reactions and they do not possess the homologous amino acid sequence with MAP in their seed proteins.
Development and validation of transient isotachophoretic capillary zone electrophoresis for determination of peptides
Authors: Waterval Joop C. M. , la Porte Charles J. L. , van 't Hof Ron , Teeuwsen Jan , Bult Auke , Lingeman Henk , Underberg Willy J. M.
Published: May 2005

Although capillary zone electrophoresis (CZE) is known for its high resolution power and low mass detection limits, the concentration detection limits are rather poor when ultraviolet absorbance detection is used. To overcome this limitation, several on‐column transient isotachophoresis (tlTP) protocols have been developed and validated for the determination of both cationic and anionic model peptides, separately. Using this preconcentration method, up to 72% of the capillary can be filled with sample solution, without any loss in resolution. Thus, without any modification of the hardware set‐up, the sensitivity is increased about two orders of magnitude. For the model cationic peptides (gonadorelin, angiotensin II) good linearity and reproducibility is observed in the 20 to 100 ng/mL concentration range. For the anionic peptides (N‐t‐Boc‐Pentagastrin and two related peptides), a ITP method was developed using a dynamically coated capillary. The coating was prepared by adding Fluorad FC‐135® to the leading electrolyte buffer. In this way a positively charged bilayer was formed on the inside of the capillary, producing an electroosmotic flow towards the outlet using reversed polarity conditions. In this way, acceptable analysis times were achieved. Using the developed tlTP method, up to 72% of the capillary can be filled with sample solution as well. The anionic peptides are separated even better than when using CZE conditions. Linearity and reproducibility in the 20‐100 ng/mL range proved to be excellent.
On‐line nonaqueous capillary electrophoresis and electrospray mass spectrometry of tricyclic antidepressants and metabolic profiling of amitriptyline by Cunninghamella elegans
Authors: Liu Chun‐Sheng , Li Xing‐Fang , Pinto Devanand , Hansen Eugene B. , Cerniglia Carl E. , Dovichi Norman J.
Published: May 2005

An on‐line nonaqueous capillary electrophoresis‐electrospray mass spectrometry (ESI‐MS) technique was developed using a commercial ion spray interface. The nonaqueous capillary electrophoresis ESI‐MS system was used to profile tricyclic antidepressants of similar structures and mass‐to‐charge ratios. We found that pure methanol can be used as a sheath liquid to obtain stable ion spray from nonaqueous capillary electrophoresis. The flow rate of the coaxial nebulizing gas affected baseline signals, separation efficiency, and migration times. Other nonaqueous capillary electrophoresis operating conditions and electrospray parameters were optimized for enhanced baseline separation and high sensitivity detection. The effect of sample stacking on separation and detection was evaluated. The calculated detection limits were approximately 3 pg injected onto the capillary. ESI mass spectra of tricyclic antidepressants from a single quadrupole MS were obtained and elucidated. The information was used to propose fragmentation pathways of the tricyclic antidepressants. The method was also used to analyze the metabolites of amitriptyline produced by the fungus Cunninghamella elegans. Sixteen metabolites were detected and most of them were tentatively identified as demethylated and/or hydroxylated, and/or N‐oxidized products.
Small scale flame‐spread testing to BS 476 part 7
Authors: Abbott C. , Chalabi R.
Published: May 2005

An apparatus based on the BS 476 Part 7 small scale flame‐spread specification, which has evolved over a number of years, is described. Many changes from the original simple gas/air furnace have been introduced, which have led to the development of a very useful flame‐spread test apparatus where all known variables are precisely controlled. The work has shown that the radiometers described in the standard do not monitor all the variables which affect flame‐spread results, and reported problems of reproducibility and variation on the large scale test, may be due to inadequate control of the furnace. The significance of the results is that the use of gas/air radian panels as the basis for flame‐spread tests needs to be re‐examined. All parameters should be carefully controlled and the entire procedure, particularly regarding the use of pilot ignition sources, needs to be reconsidered. There is an increasing need for test methods which assess materials at radiation intensities beyond that given by small ignition sources. The type of flame‐spread apparatus described in the paper may help fulfil this important requirement.
Toxicity of pyrolysis and combustion products of poly‐(vinyl chloride)
Authors: Michal Jan
Published: May 2005

The pyrolysis and combustion products of poly‐(vinyl chloride) and those of some of its polymer, especially of vinyl chloride with vinylidene chloride, were analysed using gas chromatography and gas chromatography mass spectrometry. The toxic effect of the individual products on the human organism was evaluated and presumed total toxicity of the poly‐(vinyl chloride) combustion products (0.3g PVC products per m3) was determined.
Flash points of mixtures of flammable and non‐flammable liquids
Authors: Thorne P. F.
Published: May 2005

A general theory is developed which enables closed‐cup flash‐points of mixtures of flammable and non‐flammable liquids to be predicted from a knowledge of certain properties of a flammability diagram. The theory illustrates, quantitatively, the effect of both the flame inhibiting properties of the vapour of the non‐flammable component and the relative volatility of that component. Experimental results for some mixtures of carbon tetrachloride and dichlorodifluoromethane with n‐hexane, n‐heptane and n‐octane are correlated by the theory. The theory also enables a flammability diagram to be partially constructed from standard flashpoint measurements. Such measurements for the n ‐hexane/carbon tetrachloride system are in good agreement with a published flammability diagram.
Theoretical analysis of fire and flammability tests i—precepts
Authors: Kanury A. Murty , Martin Stanley B. , Alvares Norman J.
Published: May 2005

Flammability testing is largely empirical and consists of many confusions, contradictions and unexplained factors. In order to accomplish reliable fire safety prediction and design, the empirical art of flammability testing has to develop into a quantitative engineering science in which rigorous analyses are made of the various fire phenomena as measured by existing tests. A rudimentary examination of the many existing tests shows that only a few of them measure some property of the material(s)‐fire interaction which will be sufficiently meaningful or useful to develop a scalable hazard rating system. In this paper we examine the meaning of the word 'flammability' to distinguish between the material's response to fire exposure and its contribution to the fire. The functional components of a versatile flammability hazard index are demonstrated to account for the properties of materials, of fire and—of great importance—of use and of human interaction. The promise of modeling techniques to establish these component functions is examined and the directions which future work should take to resolve the questions of fire safety are indicated.
Factors that influence the critical oxygen index of various solids
Authors: Wharton R. K.
Published: May 2005

The Critical Oxygen Index test has been used as a measure of the flammability of a wide range of substances, including plastics, textiles and liquids, since its introduction in 1966. The index, however, is only appropriate to the configuration and conditions used in the test, and extrapolation in order to predict the flammability of materials in a large‐scale fire is not valid. The index is dependent on a number of sample and test parameters and these are reviewed; the ASTM test standard, the reproducibility of the results, and certain theoretical aspects are also discussed.
Synergistic action of Sb2O3 with bromine‐containing flame retardant in polyolefins. 1—the variance in their performance versus Sb/Br ratio
Authors: Handa Takashi , Nagashima Toshiaki , Ebihara Naobumi
Published: May 2005

The synergistic action of antimony (Sb) with bromine (Br) was studied for polypropylene‐2,3‐dibromopropylpentabromophenyl ether–Sb2O3 systems at various Sb/Br molar ratios. Oxygen index, weight loss rate and heating value were used to evaluate the retardant effect. Bromine and antimony emission and their material balances were measured by gravimetric and X‐ray fluorometric analysis of heated samples at each reaction time. Retarded HBr formation in the gaseous phase through SbBr3, SbOBr and Sb4O5Br2 was proved by X‐ray diffraction analysis of heated residues and model products. SbBr3 and HBr formation were greatest at Sb/Br ratios of 1/3 and 1/4, respectively, while the highest oxygen index and the lowest weight loss rate and heating value were obtained at 1/4. Consequently, HBr will most probably produce the retardant effect rather than SbBr3. Effective synergistic action at the Sb/Br ratio of 1/4 is explained by presuming the formation of an acidic HBr.SbBr3 complex in the molten phase for the particular reaction pattern of bromine in 2,3‐dibromopropylpentabromophenyl either.
Factors affecting temperature of fire‐exposed concrete slabs
Authors: Lie T. T. , Williams‐Leir G.
Published: May 2005

The influence of the various factors that determine temperatures in fire‐exposed concrete slabs is examined, in particular that of material properties. Both experimental and theoretical studies have been carried out. From these a set of thermal properties has been derived that is representative of the properties of siliceous concrete and suitable for use in fire resistance calculations.
Neurotoxic effects of the oxidative thermal degradation products form low density polyethylene
Authors: Zitting A. , Savolainen H.
Published: May 2005

Adult male Wistar rats were exposed for 2–5 weeks, 6 h nightly, 5 nights a week, to oxidative thermal degradation products of low density polyethylene derived by heating (325°C) under an airstream in a tube oven. Chemical analysis of the degradation products in the gaseous fraction revealed a wide variety of potentially toxic molecules which included carbon monoxide (<20 ppm), formaldehyde (1.4 ppm), acrolein (0.5 ppm) and various other aldehydes (total concentration 18 ppm expressed as formaldehyde). The mean oxygen concentration was 20%. The total particulate fraction amounted to 8 mg m−3. The latter particles might have caused the detected discoloration of the rat fur. Similarly this contamination might have been the cause of a very significant increase in the duration and frequency of preening of the rats. The neurochemical effects associated with the exposure included an increase in the cerebral RNA concentration as well as initial increase in the glycosylation of cerebral protein in vitro. NADPH‐diaphorase activity was below the control range throughout the exposure while the superoxide dismutase activity displayed an increasing trend five weeks after the beginning of the experiment. The latter effects were taken as a response to potentially harmful molecules in the brain whereas the effects on the RNA and glycosylation might have resulted from a more peripheral nervous irritation.
Australian studies on fire hazard tests for internal linings of buildings
Authors: Martin K. G. , Dowling V. P.
Published: May 2005

The Australian Standard ‘Test for Early Fire Hazard Properties of Materials’ (AS 1530 Part 3, 1976) has been studied in detail as a method of assessing the fire performance of plastics wall linings under the conditions of early fire development in a room. A particular feature of the standard test is that four parameters characterizing the reaction to fire are measured concurrently. Results from the standard test have been compared to corner‐wall burns involving the same parameters as in the standard test. The suitability of these parameters and the ability of the standard test to rank the behaviour of the materials in the same order as indicated by corner‐wall burns is discussed. A general relationship between ignition time and flame spread was observed and is discussed as support for the concept of concurrent measurement of different reaction‐to‐fire parameters under the one test procedure and condition.
A new experimental method to predict the development of a fire
Authors: Laouisset M.
Published: May 2005

Among the various methods for predicting the development of a fire in real conditions we have chosen the one which works on a small‐scale model. The differences in gas concentrations, available fuel, and convection and heat transfer are recognized and discussed. A small‐scale model has been built in which any oxygen concentration, heat flux and air supply can be reproduced simultaneously. The method makes it possible to simulate a good range of conditions, and by controlling these conditions a better knowledge of the geometric reduction which is to be used in the smallscale model can be obtained.
Analytical and toxicological assessment of combustion products from cellular plastics: Comparison of ‘DIN tubular’ and ‘potts’ furnaces
Authors: Bircher Brian J. , Felstead David K. , Cunningham Anthony
Published: May 2005

The internal temperature of rigid foam undergoing combustion in the DIN tubular traveling furnace using conditions previously employed for gas generation and analysis has been studied. Unexpected findings were obtained in that the material exhibited no insulating effect and temperatures within the core of the foam were up to 25% (+125°C at 500°C) greater than has been assumed or indeed aimed for. An explanation of the phenomenon has been put forward and proved by further experiment. Suggested practices to be adopted in the future to minimize the effect are described. Using these practices the gaseous combustion products from the materials studied at 500°C were found not to change in type or distribution; however, rather more accurate description of combustion temperature is achieved. With a static furnace of the ‘Potts Pot’ type a very much smaller temperature differential is observed, hence better definition of combustion temperature is allowed.
Correlation between the critical oxygen index test and other fire tests
Authors: Wharton R. K.
Published: May 2005

The Critical Oxygen Index test is widely used as a measure of the flammability of many substances. This paper reviews attempts that have been made to compare Oxygen Index values with the results from other fire tests. Varying degrees of correlation are apparent, depending on the properties being measured in the respective tests.
Ignitability as proposed by the international standards organization compared with some european fire tests for building panels
Authors: Östman Birgit A.‐L.
Published: May 2005

Ignitability, one of the new fire test methods for building materials developing within the International Standards Organization is compared with the national fire test methods in Austria, Britain, France, Germany and Scandinavia. Different commercial wood‐based panels have been tested, including fire retardant treated panels. The International Standards Organization ignitability test measures the time to ignition at radiation intensities from 1 to 5 Wm −2; it seems to be able to distinguish between different materials in an intelligible way. An evaluation of the results of this ignitability test is discussed. One possibility which is proposed here is to calculate the mean time to ignition at different fixed radiation intensities; such a mean value simplifies the evaluation and takes into account all the test data. Agreement with the national fire test methods is rather low, since they partly measure other fire parameters; agreement with the Austrian Schlyter method, which also evaluated ignitability, is somewhat better and agreement between the national fire test methods is relatively good for wood‐based panels. This is consistent with earlier experience, which has shown that mainly new types of materials behave differently according to different national test methods.
The role of nitrogen in nitrogen–phosphorus synergism
Authors: Bakoš D. , Košík M. , Antoš K. , Karolyová M. , Vyskočil I.
Published: May 2005

Thermal analysis and limiting oxygen index flammability tests were used for elucidation of details in phosphorous‐nitrogen synergism in cotton modified with methylol phosphonopropionamide and subsequently hydrolyzed by acid. The results indicate that not all the phosphorus incorporated into the material is effective for flame retardancy purposes in the condensed phase. The comparison of modified and acid hydrolyzed cotton has shown the important influence of nitrogen in the structure of the flame retardant. A simplified theory of nitrogen‐phosphorus synergism, considering this influence, is proposed.
Determination of hydrogen cyanide in thermal degradation products of polymeric materials
Authors: Michal Jan
Published: May 2005

Thermal degradation products of nitrogen‐containing polymeric materials were analysed for hydrogen cyanide. A spectrophotometric method was used for the determination of cyanides using the formation of a characteristic absorption peak of cyanonickel(II) ion in the ultraviolet spectral region. Pyrolysis and thermooxidation products were studied and conclusions on the reproducibility of the degradation process were drawn. The effect of temperature on the quantity of hydrogen cyanide formed was studied as well.
An investigation of inorganic tin flame retardants which suppress smoke and carbon monoxide emission from burning brominated polyester resins
Authors: Cusack P. A. , Monk A. W. , Pearce J. A. , Reynolds S. J.
Published: May 2005

In view of the current demand for novel, non‐toxic, flame‐ and smoke‐ suppressant systems for synthetic polymers, certain inorganic tin compounds have been evaluated as fire retardants in a series of commercial brominated polyester resin formulations. The results obtained clearly show that zinc hydroxystannate (ZnSn(OH)6) and zinc stannate (ZnSnO3) impart beneficial properties to the polyesters in terms of flame retardancy and smoke/carbon monoxide suppression, and the improvements in performance are, in general, superior to those exhibited by tin (IV) oxide or antimony (III) oxide. The surface area and degree of dispersion of the fire‐retardant additive has been shown to have a marked effect on its efficiency and, in this connection, colloidal tin (IV) oxide is found to exhibit significantly improved flame‐retardant properties compared to powdered SnO2. Simultaneous thermal analyses (TG/DTG/DTA) and related mechanistic experiments have shown that tin additives markedly increase the amount of char formed during combustion, whereas Sb2O3, a vapour‐phase flame retardant, has little effect on char formation. The zinc stannates also appear to exhibit a significant vapour‐phase activity, and this may account for their flame‐retardant superiority to SnO2 itself.
A small‐scale flame test for fire‐resistance evaluation of rubber conveyor belts with fabric skeletons
Authors: Nakagawa Yuichi
Published: May 2005

Small‐scale flame tests were conducted on samples of six different rubber conveyor belts with fabric skeletons for use in Japanese coal mines. Each sample was claimed to be ‘flame‐resistant’ under the test condition prescribed in JIS K 6324‐1977, but results show that there are problems in this kind of test. Every sample tested sustains flame continuously when the flame exposure time exceeds a certain value or ‘ignition time’. In addition, flame duration seems to depend on the flame‐resistance of the fabric skeleton as well as on flame exposure time.
Ignition temperatures of dust layers: Flaming and non‐flaming
Authors: Mintz Kenneth J.
Published: May 2005

Combustible dusts, based on tests conducted in the Setchkin Furnace on five representative dusts, are shown to have two distinct layer minimum ignition temperatures, designated MITnon‐flaming and MITflaming. The MITnon‐flaming is the one usually reported in the literature; the MITflaming is determined by starting at a much higher temperature and working downwards. MITflaming can yield a different ranking of dust flammability than MITnon‐flaming. The MITflaming appears to be more closely correlated to the MIT of dust clouds and to the test prescribed for flammable solids in the US Code of Federal Regulations than the MITnon‐flaming.
The influence of antimony trihalides on flammability and ignitability of polyethylene
Authors: Yang J. P. , Brewer D. G. , Venart J. E. S.
Published: May 2005

The flammability and ignitability of polyethylene using antimony trihalide compounds as fire retardants was evaluated by standard methods to determine retardant effectiveness. Compared with other retardants, the antimony trihalide compounds, antimony tribromide and antimony trichloride, substantially reduced both the flammability and the ignitability of the polyethylene. The influence of retardant concentration, heat flux and type of polyethylene was also studied.
Note: Differential thermal analysis and limiting oxygen index of papyrus and its treatment with fire retardants
Authors: Abdel‐Hamid H. , El‐Engibawy A. , El‐Ashry E. S. H. , Khairy A.
Published: May 2005

The thermal behaviour of cellulose obtained from both the pith and rind of papyrus was studied and the flammability properties of paper produced from papyrus and other papers were measured. The use of flame retardants did not significantly alter the flammability properties of the papyrus paper.
Temperature distribution in a nailed gypsum‐stud joint exposed to fire
Authors: Fuller James J. , Leichti Robert J. , White Robert H.
Published: May 2005

Performance of wood‐stud walls depends on the integrity of nailed connections between the sheathing and the framing members. The performance of nailed connections has been studied at room temperature, but the effects of intense thermal loads, such as those from fire, are still poorly understood. This study examines the temperature distribution within nailed joints exposed to fire; this information is essential in modeling strength and stiffness of connections in wall systems. The finite‐element method was used to determine the effects of wood density, nail size, and type of gypsum board on temperature distribution within a set of connections. Temperature distributions were verified in nailed joints exposed in fire tests conducted in accordance with ASTM E119‐88. The principal path of heat flow through the connection was along the nail, rather than directly through the interface between gypsum board and wood. Wood species, type of gypsum board, and nail length did not change temperature distribution significantly.