scholarly journals THE 1965 ARPA-AEC JOINT LIGHTNING STUDY AT LOS ALAMOS. VOLUME 4. DISCRIMINATION AGAINST FALSE TRIGGERING OF AIR-FLUORESCENCE DETECTION SYSTEMS BY LIGHTNING,

1968 ◽  
Author(s):  
Guy E. Barasch
Keyword(s):  
Fluorescence Detection ◽  
Los Alamos ◽  
Detection Systems ◽  
Air Fluorescence

scholarly journals Comparison of buffers and detection systems for high-pressure liquid chromatography of peptide mixtures

1981 ◽  
Vol 199 (1) ◽  
pp. 43-51 ◽  
Author(s):  
K J Wilson ◽  
A Honegger ◽  
G J Hughes
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
Fluorescence Detection ◽  
Low Ph ◽  
Ease Of Use ◽  
Reverse Phase ◽  
Detection Systems ◽  
The Third ◽  
Hydrophobic Peptides ◽  
Peptide Mixtures

The chromatographic properties of peptides ranging in length from 2 to 65 residues have been compared on reverse-phase packings in three buffer systems at low pH. Of the buffers examined, two are widely used in connection with u.v. detection [(i) phosphate/acetonitrile or (ii) phosphate/propan-2-ol] and the third for fluorescence detection [(iii) pyridine/formate-pyridine/acetate/propan-1-ol]. The addition of a chaotropic salt, NaClO4, to the phosphate buffers, as first described by Meek (1980) Proc. Natl. Acad. Sci. U.S.A. 77, 1632-1636, is shown to significantly improve the chromatographic behaviour of more hydrophobic peptides. The two most commonly used detection systems, u.v. and fluorescence, are compared in terms of ease of use and sensitivity.

scholarly journals Determination of Atropine (Hyoscyamine) Sulfate in Commercial Products by Liquid Chromatography with UV Absorbance and Fluorescence Detection: Multilaboratory Study

2003 ◽  
Vol 86 (6) ◽  
pp. 1128-1134 ◽  
Author(s):  
Ugo R Cieri ◽  
R Bertrand ◽  
K K Choi ◽  
J Gagnon ◽  
P Krol ◽  
...  
Keyword(s):  
Fluorescence Detection ◽  
Atropine Sulfate ◽  
Uv Absorbance ◽  
Fluorescence Detector ◽  
Commercial Products ◽  
Detection Systems ◽  
Absorbance Detection ◽  
Acid Sodium Salt ◽  
Relative Standard ◽  
Liquid Chromatographic

Abstract A liquid chromatographic (LC) method with 2 detection systems for determining atropine (hyoscyamine) sulfate in commercial products was tested in a multilaboratory study. Depending on the type of product, sample solutions are prepared in methanol or methanol–water (1 + 1). The standard solution contains about 1.0 mg atropine sul-fate/100 mL and is prepared in the same solvent used in sample preparation. LC separations are performed on a 7.5 cm Novapak silica column. The mobile phase is prepared by mixing 970 mL methanol with 30 mL of a 1% aqueous solution of 1-pentanesulfonic acid, sodium salt. Detection is by 2 systems, UV absorbance detection at 220 nm and fluorescence detection with excitation at 255 nm and emission at 285 nm. The injection volume is 100 or 200 μL. The following materials were used for the study: 2 separate samples of tablets labeled to contain 0.4 mg atropine sulfate, 2 separate samples of extended-release tablets labeled to contain 0.375 mg hyoscyamine sulfate, one sample of atropine sulfate injection labeled to contain 2 mg/mL, and one sample of 1% (v/v) atropine sul-fate ophthalmic. Eight participants analyzed 2 separate portions of the 6 samples by both detection systems. A ninth participant analyzed the samples in duplicate but only by UV absorbance detection because of the unavailability of a fluorescence detector. The relative standard deviation (RSD) between laboratories ranged from 1.4 to 3.3% for samples of tablets and injections but higher for ophthalmic solutions (5.1–5.2%). A linearity study was conducted in the originating laboratory before the multilaboratory study with 5 solutions ranging in concentration from 0.80 to 1.20 mg atropine sul-fate in 100 mL. Average recoveries were 100.0% by UV absorbance detection and 99.9% by fluorescence detection; the RSDs were 1.1 and 1.2%, respectively.

Automated enzyme assays by use of a centrifugal analyzer with fluorescence detection.

1981 ◽  
Vol 27 (2) ◽  
pp. 256-262 ◽  
Author(s):  
K W Pearson ◽  
R E Smith ◽  
A R Mitchell ◽  
E R Bissel
Keyword(s):  
Fluorescence Detection ◽  
Cathepsin B ◽  
Control Group ◽  
Enzyme Assays ◽  
Fluorometric Detection ◽  
Detection Capability ◽  
Serum Samples ◽  
Fluorescence Detector ◽  
Detection Systems ◽  
Illustrative Application

Abstract The first commercially available centrifugal analyzer having fluorescence detection capability was used to develop kinetic fluorometric assays for several proteinases. The substrates were all synthetic oligopeptides incorporating 7-amino-4-trifluoromethylcoumarin, a molecule that can be detected either spectrophotometrically or fluorometrically. We thus compared the centrifugal analyzer spectrophotometric and fluorometric detection systems, finding fluorescence detection to be 50-fold more sensitive. We also compared the sensitivity of the fluorescence detector to that of a conventional spectrofluorometer by determining the minimum detection limit for each enzyme on both instruments; we found them to be similar in sensitivity. As an illustrative application, we measured the cathepsin B-like activity in serum samples from 55 women. The median enzyme activity of women taking oral contraceptives and pregnant women was increased two- and threefold, respectively, over the control group (about 5% CV within run, and 10% CV between runs).

Energy-Resolving X-ray Fluorescence Detection Using Synthetic Multilayers

1998 ◽  
Vol 5 (4) ◽  
pp. 1227-1234 ◽  
Author(s):  
K. Zhang ◽  
G. Rosenbaum ◽  
G. Bunker
Keyword(s):  
Fluorescence Detection ◽  
Detection System ◽  
Array Detector ◽  
Wide Energy Range ◽  
Ionization Chambers ◽  
X Ray ◽  
Detection Systems ◽  
Wide Energy ◽  
Fluorescence Detection System ◽  
X Ray Absorption

The potential of synthetic multilayers for energy-resolving the X-ray fluorescence in X-ray absorption fine structure (XAFS) experiments is discussed. Two detection systems, one using curved multilayers and the other using graded multilayers to select X-ray fluorescence photons, have been designed to cover a wide energy range with a usefully large solid angle. Such a detector will be more advantageous than the barrel-like crystal-array detector because of the unique properties of synthetic multilayers, such as larger horizontal acceptance angles and bandwidth. In addition, the detector should be much simpler to construct and readily accommodates energy changes, especially the detector using graded multilayers. Comparison of the multilayer array detector with conventional detectors, such as ionization chambers and conventional 13-element Ge detectors, shows that the proposed system will be superior, particularly with the increased photon fluxes available from insertion devices and with decreased sample concentration, since this detection system eliminates the `bad' photons before they enter any X-ray detector. Consequently, the X-ray detector proper for this system does not suffer from the incident-count-rate bottleneck common to current X-ray fluorescence detectors with energy resolution by signal processing. Thus, this new fluorescence detection system will provide tremendous opportunities for XAFS measurements on dilute systems, such as biological systems, at third-generation synchrotron sources.

The Potentials of Scanning Microscopy

1968 ◽  
Vol 26 ◽  
pp. 352-353
Author(s):  
A. V. Crewe
Keyword(s):  
Salient Feature ◽  
Secondary Emission ◽  
Resolving Power ◽  
X Rays ◽  
Scanning Microscope ◽  
Forming Process ◽  
Additional Tool ◽  
Detection Systems ◽  
Conventional Microscope ◽  
Present Information

If the resolving power of a scanning electron microscope can be improved until it is comparable to that of a conventional microscope, it would serve as a valuable additional tool in many investigations.The salient feature of scanning microscopes is that the image-forming process takes place before the electrons strike the specimen. This means that several different detection systems can be employed in order to present information about the specimen. In our own particular work we have concentrated on the use of energy loss information in the beam which is transmitted through the specimen, but there are also numerous other possibilities (such as secondary emission, generation of X-rays, and cathode luminescence).Another difference between the pictures one would obtain from the scanning microscope and those obtained from a conventional microscope is that the diffraction phenomena are totally different. The only diffraction phenomena which would be seen in the scanning microscope are those which exist in the beam itself, and not those produced by the specimen.

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