Detection using

Surface Crack Detection Using Magnetic Particle Techniques and Penetrant Inspection Method. 

Kneipp K, Wang Y, Kneipp H, Itzkan I, Dasari R R and Feld M S 1996 Approach to single molecule detection using surface-enhanced Raman scattering ICORS 98 XVth Int. Conf on Raman Spectroscopy ed S A Asher and P B Stein (New York Wley) pp 636-7... 

Even if the intensity changes are only of the order of 1 %, they may nevertheless be reliably detected using... 

Aibrecht T R, Grutter P, Florne D and Rugar D 1991 Frequency moduiation detection using high-Q cantiievers for enhanced force microscope sensitivity J. Appl. Phys. 69 668... 

Schematic diagrams of two approaches to on-coiumn detection using UV/Vis absorption spectroscopy.

Determination in the Atmosphere. Trace amounts of HCl in the atmosphere are detected using krypton homologues as detectors (78),... 

Table 3. Clinically Important Substances Detected Using Coupled Enzyme Reactions...

Most sample components analyzed with electrophoretic techniques are invisible to the naked eye. Thus methods have been developed to visualize and quantify separated compounds. These techniques most commonly involve chemically fixing and then staining the compounds in the gel. Other detection techniques can sometimes yield more information, such as detection using antibodies to specific compounds, which gives positive identification of a sample component either by immunoelectrophoretic or blotting techniques, or enhanced detection by combining two different electrophoresis methods in two-dimensional electrophoretic techniques. 

Whereas the cycloaddition of arylazirines with simple alkenes produces A -pyrrolines, a rearranged isomer can be formed when the alkene and the azirine moieties are suitably arranged in the same molecule. This type of intramolecular photocycloaddition was first detected using 2-vinyl-substituted azirines (75JA4682). Irradiation of azirine (54) in benzene afforded a 2,3-disubstituted pyrrole (55), while thermolysis gave a 2,5-disubstituted pyrrole (56). Photolysis of azirine (57) proceeded similarly and gave 1,2-diphenylimidazole (58) as the exclusive photoproduct. This stands in marked contrast to the thermal reaction of (57) which afforded 1,3-diphenylpyrazole (59) as the only product. 

Methyl metacrylates, alcohols, aromatic and aliphatic carbohydrates, acetic ester acids are detected using he vapour-phase method. 

Visual identification prior to failure is difficult due to the typical tightness of stress-corrosion cracks. A low-power hand lens will greatly aid determination. Crack enhancement may be achieved through the use of dye penetrants. Severe cracking may be detectable using ultrasonic, radiographic, or acoustic emission techniques. 

Most defects can be detected using one or more appropriate nondestructive testing techniques. However, in the absence of routine nondestructive testing inspections, identification of defects in installed equipment is generally limited to those that can be observed visually. Defects such as high residual stresses, microstructural defects such as sensitized welds in stainless steel, and laminations will normally remain undetected. Defects that can be detected visually have the following features ... 

The presence of a COOH functionality on a polystyrene resin can be detected using a 0.25% solution of malachite green-oxalate in ethanol in the presence of a drop of triethylamine. Beads with COOH functionalities are coloured dark green or appear as clear gel beads [Attardi, Porcu and Taddei Tetrahedron Lett 41 7391 2000]. 

Mabbit, Allen, and Andrew Parker. Methane, and Carbon Dioxide Detection Using LED Sources. Sensor Rev. 16 (1996), pp. 38-41. 

Nondestructive Detection Using Other Physical Methods 2.5.1 Spectral Phenomena... 

Acidic and basic substances can be detected using pH indicators. Indicators changing color in the acid region are primarily employed. They are apphed to the chromatogram by dipping or spraying with 0.01 to 1% solutions. The pH is... 

An amino group may take any of three possible positions in the five-membered isoxazole ring, giving rise to three tautomeric forms for 70 and 71 and four forms for 72 [76AHC(S1), pp. 416, 444, 445 84CHEC-I(5)1]. However, only amino structures 70a-72a have been detected using IR- or NMR-spectroscopic techniques (Scheme 33). 

The tautomeric relationships for benzisothiazolamidines 100 are more complicated (Scheme 38) (95AP217). In the solid, compound 100 (R = Ph, R = H) exists in the amino form 100a, whereas in a DMSO-d solution at 298 K the tautomers 100b,c have also been detected using NMR spectroscopy. 

K. Yamashita, M. Motohaslii and T. Yashiki, Sensitive high-performance liquid cliro-matographic determination of propranolol in human plasma with ultraviolet detection using column switcliing combined with ion-pair cliromatography , J. Chromatogr. 527 196-200(1990). 

Figure 12.20 SFC-GC analysis of a sample of aviation fuel (a) SFC separation into two peaks (b and c) coixesponding GC ttaces of the respective peaks (flame-ionization detection used throughout). Reprinted from Journal of High Resolution Chromatography, 10, J. M. Levy et ah, On-line multidimensional supercritical fluid chromatography/capillary gas chromatography , pp. 337-341, 1987, with permission from Wiley-VCH.

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