Optical detection system

Explosion Suppression With explosion suppression, an incipient explosion is detected and—within a few milhseconds—a suppressant is discharged into the exploding medium to stop combustion. Pressure and optical detection systems are used suppressors are pressurized and release the suppressants when actuated by an electroexplosive device. 

Monitor exterior wall temperature with infrared optical detection system, and operating instructions for operator response if high temperature signal occurs... 

For IBSCA analysis, standard HV or, better, UHV-equipment with turbomolecular pump and a residual gas pressure of less than 10 Pa is necessary. As is apparent from Fig. 4.46, the optical detection system, which consists of transfer optics, a spectrometer, and a lateral-sensitive detector, is often combined with a quadrupole mass spectrometer for analysis of secondary sputtered particles (ions or post-ionized neutrals). 

The reactants are then mixed in various proportions, and the sedimentation ratio (scompiex/smucin)—the ratio of the sedimentation coefficient of the complex to that of the pure mucin itself—is used as the measure for mucoad-hesion. The ultra-violet absorption optics on the XL-A or XL-1 ultracentrifuge have been used as the main optical detection system. Although the polysaccharide is generally invisible in the near UV ( 280 nm), at the concentrations normally employed the mucin—in uncomplexed and complexed form—is detectable. 

Optical fibre based optical detection systems offer a number of advantages over bulk optical sensing systems. The principal one is that a robust passive sensing head may be remoted from the monitoring station a factor giving particular advantages in severe environments. This also allows... 

Figure 1. Schematic of a differential fibre-optic detection system (redrawn from diagram in Hordvik et al.).

Detection in CE is performed on-column and frequently with optical detection systems. On-column detection minimizes zone broadening as... 

While the alkyl chain distribution is determined on a non-polar RP8 and RP18, EO homologue distribution is determined using a polar phase. AEOs are not UV-absorbing species, so they cannot be directly determined by HPLC followed by standard optical detection systems (UV and FL), unless suitable derivatives are prepared [2], Because of this, methods based on liquid chromatography-mass spectrometry [77-79] are currently considered as the benchmark procedure that gives sufficiently high selectivity and sensitivity. 

Of the analytical procedures used for the determination of LAS in soils (Table 6.7.1), most methods rely on (Soxhlet) extraction with methanol, followed by clean-up on SPE cartridges (RP-C18 and/or SAX) and final quantitative measurements by HPLC—UV/FL. Applying this protocol, detection limits were achieved ranging between 0.05 and 5 mg kg-1 depending on the matrix, the enrichment factor and the optical detection system employed. 

Cottrell, J.S. Evans, S. The Application of a Multichannel Electro-Optical Detection System to the Analysis of Large Molecules by FAB-MS. Rapid Commun. Mass Spectrom. 1987, 7, 1-2. 

A special mention in the field of enantioselective HPLC separations must be made of chiro-optical detection systems, such as circular dichroism (CD) and optical rotation (OR), which can be also used to circumvent the low UV detectability of chromophore-lacking samples [40, 61]. While sensitivity of chiro-optical detection is not always sufficient to perform enantiomeric trace analysis, the stereochemical information contained in the bisignate spectropolarimetric response is useful in establishing elution order for those compounds not available as single enantiomers of known configuration. An example of application of different online detection systems (UV and CD at 254 nm) in the enantioselective separation of a racemic sulfoxide on a commercially available TAG CSP is reported in Figure 2.12, under NP conditions. 

Details of the picosecond pulse radiolysis system for emission (7) and absorption (8) spectroscopies with response time of 20 and 60 ps, respectively, including a specially designed linear accelerator (9) and very fast response optical detection system have been reported previously. The typical pulse radiolysis systems are shown in Figures 1 and 2. The detection system for emission spectroscopy is composed of a streak camera (C979, HTV), a SIT... 

PILETSKY S A, PILETSKAYA E V, EL SKAYA A V, LEVI R, YANO K and KARUBE I (1997), Optical detection system for triazine based on molecularly-imprinted polymers , Anal Lett, 30, 445-455. 

FIGURE 7.4 The acousto-optical detection system. Deflection of the incident laser beam by the acousto-optic crystal. Deflection angle is determined by the frequency of the acoustic wave [683]. Reprinted with permission from John Wiley Sons. 

Warner and co-workers justify the elaborate optical/detection system and the time commitment required per analysis on the basis of the additional sensitivity available using fluorescence detection, and on the multidimensional CD information available. For applications in which two, or more CD active fluorophores may be present, the ability to provide both an excitation and emission FDCD profile for the sample may allow differentiation of the individual components without pre-separation. Replacement of the mechanical mechanism for prism movement with an electro-optical device may improve both the SNR and reduce the time required per sample. These improvements will greatly facilitate general application of this multidimensional approach to FDCD measurements. 

Samples were irradiated by a 10 ps single or 2 ns electron pulse from a 35 MeV linear accelerator for pulse radiolysis studies (17). The fast response optical detection systems of the pulse radiolysis system for absorption spectroscopy (18) is composed of a very fast response photodiode (R1328U, HTV.), a transient digitizer (R7912, Tektronix), a computer (PDP-11/34) and a display unit. The time resolution is about 70 ps which is determined by the rise time of the transient digitizer. 

Optical Detection Systems for Ultrafast Pulse Radiolysis... 

Fig. 8. Time ranges of various optical detection systems. The dotted line for transient digitizer indicates the highest-performance configurations, the solid line routine ones.

The experimental arrangement consists of a simple molecular beam apparatus, a pulsed tunable dye laser for exciting fluorescence, and a gated optical detection system. 

For low dose per pulse, a large value of Ge is desirable when the response time of the optical detection system is slow, the product should be relatively stable. 

The optical detection system is effectively a spectrophotometer and the following should be checked regularly to ensure that it is working correctly ... 

The major advantage of electrochemical immunoassays is the fact that it s based on the use of a non-optical detection system, which makes it possible to detect signals in the presence of whole blood samples. There are three different ways in which electrochemistry is used in a detection system. 

Figure 13.8. Analytical ultracentrifuge equipped with a UV-vis optical detection system. The sliding slit at the photomultiplier allows positional recording of the absorbance along the cell.

Figure 13.11. Results for a moving-boundary ultracentrifuge experiment using different optical detection systems and a double-sector cell. Part (a) is a graphical representation, (b) is the result of an uv photograph, (c) is a plot of absorbance versus distance (from b), id) is a photograph obtained with Schlieren optics, (e) is an interference diagram obtained using Rayleigh optics, and (f) is another interference diagram, obtained with Lebedev optics.

Once separated, proteins may be detected either by staining followed by quantification using a densitometer or by direct measurement using an optical detection system. 

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