Photographic Detection Research Articles

Detection of Chemiluminescent Labeling Compounds by Photographic Method. Preliminary Investigation on 1,10-Phenanthroline-Hydrogen Peroxide and Luminol-Hydrogen Peroxide Systems

The following two chemiluminescent reaction systems were investigated for the photographic detection of ultra-micro amounts of analyte on an agarose gel plate. 1) Reaction of 1,10-phenanthroline with hydrogen peroxide, which is catalyzed by copper(ll) or osmium(VIII). 2) Reaction of luminol with hydrogen peroxide, which is catalyzed by iron(lll) complex. Chemiluminescent light was detected using a high-speed instant photographic film, and amounts as small as 9×10-10 mol of 1,10-phenanthroline or 2×10-18 mol of iron complex of tetraphenylporphinetrisulfonic acid were detected by this method.

Porous-Core Electrode for Emission Spectroscopy

A core was made of porous graphite to fit a preformed electrode. This porous-core electrode replaces old popular methods using graphite powder as an absorbent to accomplish concentration of liquid samples, but without causing contamination problems of Teflon® ware. When the amount of sample solution is not limited, a concentration of several thousand times is possible, to extend detection limits required by the modern electronics industry. High-purity water, solvents, volatile acids, and alkali were concentrated, and ultra trace impurities were determined. Some organic material can be ashed at 400°C on the electrode for arcing. Boron in trichlorosilane was separated with an addition of mannitol and routinely determined in low ppba range. The cost of this operation is a small fraction of that for new instrumentation required for achieving these sensitivities. The old spectrograph with a dc arc source unit and photographic detection has found some applications to meet new stringent requirements. The technique should be able to be easily applied to the determination of metallic impurities in trichlorosilane, dichlorosilane, hydrogen chloride, and others.

Dosimetry of 102–106 Gy 60Co γ-rays with photographic detectors without processing

To study intense γ-rays exposures, thermal neutron activation and X-ray fluorescence techniques were applied to determine Ag in unprocessed but fixed Kodak NTA and INDUSTREX films. Exposures as high as 106Gy which cannot be evaluated in processed films could be measured with a reasonable standard deviation by selecting suitable films.

Pyrolysis and soft ionization mass spectrometry of aquatic/terrestrial humic substances and soils

The rapid, reproducible, chemical characterization of complex environmental materials such as plants, humic substances and whole soil can be performed by controlled thermal degradation. Except for drying and milling no pre-treatment of the samples is required. Biomacromolecular cleavage during a short degradation step directly in the ion source of a mass spectrometer results in the production of high-mass chemical subunits. Short reaction times and small amounts of sample favour the generation of large, thermal fragments, i.e., chemical building blocks, which can be identified and correlated with the structure of the polymeric biomaterials investigated. The principal aim is to monitor the primary, thermal fragmentation by high molecular ion intensities of the pyrolyzates and to avoid consecutive, mass spectrometric fragmentation as far as possible. For the detection and identification of the pyrolysis (Py) products, a combination with time-/temperature-controlled mass spectrometry (MS) is used. Typical heating rates are 0.2–10°C/s and the temperature range is 50–800°C. Soft ionization techniques such as field ionization (FI), field desorption, chemical ionization (CI) and, to some extent, fast atom bombardment are employed in the positive and negative modes. The results of direct Py-MS are supported by high-resolution mass measurements using electric or photographic detection and Curie-point pyrolysis in combination with gas chromatography-electron ionization/FI/CIMS and library searches for the identification of the pyrolysis products. Fingerprinting and time-resolved Py-MS of aquatic and terrestrial humic substances are reported. The methodology for the investigations of dynamic processes during the volatilization and thermal decomposition of these complex biomaterials is illustrated. Weight loss curves and the temperature function of accurate molecular weight averages for aquatic fulvic and humic acid are derived from the Py-FIMS data. Initial results on the differentiation of soil horizons in a moder profile by Py-FIMS and pattern recognition are presented. In particular, the chemometric evaluation appears promising for future Py-MS studies of humic substances and whole soils, but also for fossil fuels, synthetic polymers and food. In an integrated approach, the linking of conventional chemical and spectroscopic data with the high-mass signals in pyrolysis-mass spectra will be the focus of forthcoming work. Preliminary results for combining wet-chemical data with those of 13C nuclear magnetic resonance, Fourier transform infrared and electron spin resonance spectroscopy are put forward in this survey. Finally, initial results of pilot studies to detect biocides such as atrazine directly in soils using Py-FIMS are demonstrated.

Astronomers Seek High Resolution

Astronomical advances often depend upon technological advances. In recent years charge‐coupled‐device detectors on existing telescopes have reached photon efficiencies approaching 100%, significantly better than those of photographic detectors. (See PHYSICS TODAY, March, page 19.) “The 5‐meter Hale telescope with a charge‐coupled‐device detector is equivalent to a 50‐meter diameter telescope equipped with 1948 photographic plates,” says Peter Waddell (University of Strathclyde, Glasgow), who is trying to develop large membrane mirrors that may eventually be used in space. “Detectro sensitity cannot go much further, which is why astronomers are looking once again for larger telescopes.”

Photographic detection of luminescence in Escherichia coli containing the gene for firefly luciferase

The gene for firefly luciferase ( luc) can be used as a generalized genetic probe. A method that aids in the analysis of shuttle vectors containing luc by allowing verification in Escherichia coli of a functional coding sequence is presented here. Colonies containing a functional form of luc are detected on film after luciferin is added to initiate the luminescent reaction. Two conditions, lowering the pH of the environment and maintaining aerobic conditions, were found to greatly improve the sensitivity of the assay. This technique may be useful in the development of genetic constructs that alter the natural coding sequence of luc, such as in gene fusions.

Discrete electronic-vibrational fluorescence spectra in the low-pressure phenanthrene and naphthalene vapors

In recent years considerable attention has been paid to developing methods for analysis and control of air pollutants. In this work the results of the study on quasiline fluorescence spectra for phenathrene and naphthacene in the gas phase are presented. Despite the fact that phenanthrene is a stereoisomer of anthracene, the shapes and intensities of their absorption and fluorescence spectra are markedly different. The oscillator strength of the first electronic transition in anthracene vapors is 50 times larger than that for the phenanthrene vapor (0.1 and 0.002, respectively). Therefore, the studies of the quasiline fluorescence spectrum of the phenanthrene vapor required a long exposition period (from 7 to 31 h) during the photographic detection. It is known that phenanthrene exhibits a characteristic quasiline spectrum in the 34584000-A range in frozen solutions. The authors have also investigated the possibility of obtaining structured quasiline vapor spectra for a more complex aromatic compound such as naphthacene which comprises four benzyl rings. In conclusion, the quasiline fluorescence spectra for phenanthrene and naphthacene in the gas phase have been obtained for the first time. In certain experimental conditions, phenanthrene and naphthacene emit wellresolved quasiline spectra which are dependent on the excitation frequency, temperature, and vapormore » pressure. For both compounds there is a frequency range for quasiline fluorescence excitation for which a shift of the quasiline spectrum occurs if the excitation frequency is changed within that range. Also more accurate values for the frequencies of the O-O electronic transition in phenanthrene and naphthacene have been obtained. Diagrams are included.« less

Photographic Detection of Amblyogenic Factors

Refractive errors were determined photographically in a group of infants and children and were compared to conventional cycloplegic retinoscopy. The refractor consisted of a mirror telephoto lens and strobe flash designed to mimic the action of a retinoscope. Significant amblyogenic conditions such as anisometropia and high isoametropia were detectable. Strabismus and media opacities were also recordable. The technique provides a potential mass suited for infants.

33] Photographic detection of chemiluminescent and bioluminescent reactions

In chemiluminescent and bioluminescent assays, light emission is usually measured with a photomultiplier tube (PMT) or a silicon photodiode. A less expensive and simpler alternative is photographic film. The combination of photography and either chemiluminescence or bioluminescence provides a simple and convenient system for assaying a wide range of substances. The kinetics of light emission—that is, a flash versus a prolonged emission—is important factors in the design of instrumentation for photographic assays. In reactions that produce a prolonged emission, the use of film poses no major problems as the reactions can be initiated prior to exposure to the film. In their simplest form, the results of photographic assays are assessed by visual comparison of exposures (black through grey to white) produced by samples and standards. Further quantitation can be achieved if the reaction vessel is held in a cylindrical cavity above the film. The area of film exposed beneath the cavity is dependent upon the intensity of light emission, and intensity is proportional to the diameter of the exposed zone. Photographic results can also be quantitated using a densitometer. This method is employed to determine allergen-specific IgE levels from photographic prints obtained in MAST chemiluminescent enzyme immunoassays.

A Rapid Method for Assessing the Efficacy of Biocides Applied to Textile Materials

A novel method is presented for detecting and measuring microbial growth on wool textile substrates and for determining the efficacy of biocides in textile applications, based on the bioluminescent light emission and photographic detection of adenosine triphosphate (ATP) released from mildew‐causing microbes. The method will facilitate the evaluation of biocide performance, providing preliminary results within a matter of hours.

Construction of an Electron Diffraction Unit for Gases as Fitted for the Use of Photographic Sheet Films

A new type of electron diffraction unit for the structural determination of gases has been constructed. The unit employs a telefocus electron gun of the Steigerwald type. Plastic sheet films are used as the photographic detector instead of the glass plates usually used in such units. To check the reproducibility of the film-setting and other relevant functions of the unit, a large number of diffraction patterns of CS2 were taken and the values of the C-S distance were examined. The reproducibility was found to be as good as that in experiments using glass plates. It was thus concluded that sheet films are suitable for use as photographic detectors in high-precision diffraction experiments. The systematic errors inherent in the present unit are discussed in this paper.

Relevance of analytical pyrolysis studies to biomass conversion

The principles and methods of soft ionization mass spectrometry in combination with pyrolysis of macromolecules are outlined. Essential features of the newly developed techniques are the extension of the recorded mass range and the almost exclusive formation of molecular ions of the pyrolyzates. Using field ionization and field desorption mass spectrometry at low and high mass resolution, with electrical and photographic detection, pyrolysis products of biomass were analyzed for the first time. The results of flash pyrolysis by Curie-point heating and thermally programmed degradation of biopolymers are compared. The main topic is the evaluation of the methodology for time- and temperature-resolved pyrolysis. The thermograms and pyrolysis mass spectra obtained enable the study of pyrolysis reactions and the chemical fingerprinting of complex biological matter. The kinetics for the devolatilization of individual chemical species or classes of compounds can be monitored. Curie-point pyrolysis of biopolymers such as kappa-carrageenan and time-programmed degradation of cellulose and lignin are reported. Furthermore, preliminary investigations of pine wood and coal illustrate the potential of the introduced methods.

Temperature and Electron Density Measurements in a DC Glow Discharge

Data on the glow discharge have been accumulated by photographic detection with an echelle spectrometer. Intensity, excitation temperature, and electron density results are reported for the cathode dark space, negative glow, and Faraday dark space regions of the plasma for three values of discharge current and five values of fill gas pressure. It is concluded that neither excitation temperature nor electron density is a useful descriptor of excitation conditions in low pressure plasmas. Excitation is interpreted in terms of an ionization-radiative recombination model, and intensity of argon atomic emission is shown to be correlated with the product of discharge current and argon ionization cross section.

Rapid assays based on immobilized bioluminescent enzymes and photographic detection of light-emission

Sensitive assays have been developed for adenosine 5'-triphosphate, the reduced form of nicotinamide adenine dinucleotide, cholyl glycine and alcohol, with immobilized and co-immobilized preparations of bacterial and firefly luciferase as reagents. With high-speed (ASA 20000) instant photographic film as detector, picomole amounts of the various analytes can be detected rapidly. The simplicity and convenience of the analytical combination of co-immobilized bioluminescent enzymes and photographic film for the detection of light make this an ideal technique for rapid screening tests.

Comparison of photographic and photoelectric detection for multi-element analysis by inductively coupled plasma atomic-emission spectrometry

The relative performances of two detecting and recording systems used in inductively coupled plasma atomic-emission spectrometry for multi-element analysis are compared. Whereas the more generally used scanning monochromator system has superior sensitivity and precision, the spectrographic system incorporating a computer-controlled microdensitometer provides a permanent record of the spectrum, requires no pre-selection of spectral lines, has a better ability to identify correctly emission lines and is more economic in terms of sample volume and time. The merits of both approaches are discussed in relation to multi-element analysis of diverse materials.

Considerations in Photographic Detection for Very Large Telescopes

AbstractCurrent practice with four-meter reflectors is reviewed and the good match with fine-grained photographic plates of high DQE is examined. The present designs of 15-meter-class telescopes appear to point to instruments with a large flat focal plane and an image scale in the 5 arc sec/mm range. This requires an emulsion of considerably larger microcrystal size than currently used. Extension of the present emulsion type to the required grain size is not likely to be efficient; however, the use of new emulsion technologies should offer the opportunity to devise appropriate photographic detectors for use with an f/6, 5 arc sec/mm telescope. A gain in detective quantum efficiency appears possible.

Fibre Optics at the UK Schmidt Telescope

The four-fold advantage over a conventional 4 m reflector which naive information theory confers on the 1.2 m UK Schmidt telescope (Dawe and Watson 1982, Watson 1983) is only approachable in practice under certain rather specific conditions. These relate principally to the surface distribution on the sky of the object classes of interest, and the type of detection employed. Clearly, for general survey work with sky-limited photographic detection, the information advantage is high, but it can be demonstrated (Dawe and Watson 1983) that the relatively new technique of multi-object fibre-optics spectroscopy (eg Hill et al. 1980, 1982, Gray 1983, Lund and Enard 1983) with linear detectors offers very high potential in certain regimes of operation. In particular, the UK Schmidt telescope (UKST) equipped with 400 fibre channels has four times the effective light grasp (= number of fibres utilized × aperture) of a 4 m reflector (with a 1 deg field and equipped with any number of fibres) for target objects with surface densities between approximately 1 and 10 per square degree (Dawe and Watson 1983). Objects ranging from galactic variable stars to quasars lie within these limits, but of especial interest are galaxies, whose apparent luminosity function in this range of surface densities runs from magnitudes 15 to 17 (MacGillivray, private communication). Large-scale, medium accuracy (60 km s−1) redshift surveys of galaxies within this magnitude range promise to be extremely fruitful (Davis 1982) and are easily within the reach of the UKST fibre-coupled to a CCD spectrograph (Watson and Dawe 1984).

Preliminary Evaluation of Capabilities of Photoelectric Detection of High Resolution Molecular X-ray Fluorescence Spectra with a 5 M Grating Ultrasoft X-ray Spectrometer

Abstract Using our recently developed high resolution 5 M grating spectrograph we have reported previously on the capabilities of photographic detection for obtaining molecular x-ray fluorescence spectra.(1,2) Accordingly, we indicated that in spite of a relatively inexpensive monochromator source the signal to noise ratio on O K in Li3 PO4 at equivalent instrumental resolution was of the same order of magnitude as that obtained by Wiech's group using photoelectric detection and the DORIS storage ring as a, source.(3)

A Low Cost Spectrographic Attachment for an Echelle Spectrometer

The report describes a simple, low cost photographic attachment for an echelle spectrometer. The crossed dispersion prism/echelle grating system provides a high resolution spectrum in a compact two dimensional format. It has been estimated that the echelle spectrum obtained on a 4 by 5 in. plate would require an 8-m long record if obtained with a conventional grating spectrograph. For many types of spectroscopic studies, the photographic plate is the detector best equipped to take advantage of the dispersing power of the echelle system. The advantages of photographic detection have been discussed in recent report.

The application of inductively-coupled plasma emission spectrometry to the determination of impurities in boron and boron compounds

Good sensitivity is achieved for 25 elements in boron, after removal of the matrix with hydrofluoric acid. The ten most common elements are studied in detail, and an overall precision of 10–15% is achieved using photographic detection. Agreement with results obtained by epithermal neutron activation analysis and flame atomic absorption spectrometry is good.