Two detection

At the column outlet, either of two detection methods are employed ... 

Consider again two detection elements, and suppose an ion beam has been dispersed in time such that ions of m/z 100 arrive at each of several elements (Figure 30.5). In this TOF mode, the next ion of m/z 101 has not yet arrived, and the ion of m/z 99 has arrived previously. Although the m/z ions are dispersed in time over a region of space and strike different elements of the detector, they are collected and monitored simultaneously because all of the microchannels are electronically connected. The operation of the microchannel plate is much easier than that of the array because all the elements are monitored as one at the plate, while each element must be monitored separately in the array. The microchannel plate detector is tremendously useful for those cases in which ions... 

A flow trace technique in which Freon is injected into the constream, and flight time between two detection points is measured. 

Two detection techniques were tested, LIBS for the Cu-Ag-Si samples and LA-TOF-MS for the TiN-TiAlN samples. 

The microchemical detection methods are the most economical methods and the simplest for the chemist to carry out. No expensive apparatus is required and in certain circumstances they can be combined with the two detection methods mentioned above. 

A molecular probe with dual output signals offers two detection modes allowing use of the same probe in different environments. We have demonstrated how an AB2 self-immolative dendron with double quinone methide release mechanism can be applied to create a molecular probe with UV-Vis and fluorescence modes for the detection of a specific catalytic activity.15 The molecular probe is illustrated in Fig. 5.36. The central unit of the probe (the molecular adaptor) is linked to an enzymatic substrate that acts as a trigger and to two different reporter molecules. Cleavage of the enzymatic substrate triggers the release of the two reporters and a consequent activation of their signals. 

In general, one energy and angle analyser, denoted by f, detects emitted electrons that are faster than those detected in the other analyser, denoted by s. (Due to the indistinguishability of electrons it does not matter which is the scattered electron or indeed whether their energies are equal, as is the case in symmetric kinematics.) To ensure that the two detected electrons come from the same event, fast timing techniques are used [1,2]. 

Quadrature detection Preferred system of signal detection using two detection channels with reference signals offset by 90°. 

Center for Healthcare Technologies at Lawrence Livermore National Laboratory in Livermore, potentially capable to measure pH at or near the stroke site29. The probe is the distal end of a 125 pm fibre tapered up to a diameter of 50 pm. A fluorescent pH-indicator, seminaphthorhodamine-1-carboxylate, is embedded inside a silica sol-gel matrix which is fixed to the fibre tip. Excitation of the dye takes place at 533 nm and the emission in correspondence of the acid (580 nm) and basic (640 nm) bands are separately detected. The use of this ratiometric technique obviates worrying about source fluctuations, which have the same effects on the two detected signals. The pH sensor developed was first characterised in the laboratory, where it showed fast response time (of the order of tens of seconds) and an accuracy of 0.05 pH units, well below the limit of detection necessary for this clinical application (0.1 pH units). The pH sensor was also tested in vivo on rats, by placing the pH sensor in the brain of a Spraque-Dawley rat at a depth of approximately 5 mm30. 

There are two detection sensitivities that are of interest for characterizing the BioCD performance. The first is a metrology sensitivity that includes experimental noise sources such as the laser intensity fluctuations and detector noise, but does not include variability of the protein spots on the disc. The second detection sensitivity is under actual assay conditions in which antibody spot variability plays a dominant role. For both of these sensitivities, it is important to define a scale-free sensitivity that is an intrinsic property of the detection platform. 

Bismuth Molybdates. Bismuth molybdates are used as selective oxidation catalysts. Several phases containing Bi and/or Mo may be mixed together to obtain desired catalytic properties. While selected area electron diffraction patterns can identify individual crystalline particles, diffraction techniques usually require considerable time for developing film and analyzing patterns. X-ray emission spectroscopy in the AEM can identify individual phases containing two detectable elements within a few minutes while the operator is at the microscope. 

In this example, there are two detection systems and two reaction opportunities. These yield three paths that lead to no adverse consequences and four paths that lead to failure with overflow as the consequence. The point is that sometimes there are more opportunities for things to go wrong than to go right. When a system or process fails, it may he difficult to trace the reasons for its failure. Based on available historic incident data, the anatomy of a major incident is rarely simple and rarely results from a single root cause. Serious incidents typically involve a complex sequence of occurrences and conditions. This sequence can include ... 

Two detectives came to my door a few weeks ago and they chapped [knocked on] the door and they went can you let me in, it s CID , and I fell against the wall... See when they says CID , either she d done something really bad or she was dead...when Amanda s drug taking, see your phone You re feart [afraid] to answer your phone, you re feart to go to the door, that s the way you re living. 

One of the major disadvantages of HPLC, despite all of the progress in the past years, is a serious lack of detectors, particularly universal detectors, which can match the sensitivity of GC detectors. The best HPLC detectors currently available are (spectro) photometric and (spectro) fluorimetric detectors. It seems logical, therefore, to solve the immediate detection problems at least partially by UV- and fluorescence-derivatization techniques. Recent activities by several research groups show an increased interest in such an approach. Derivatization techniques are not restricted to these two detection modes. Reaction products which yield good MS signals (a favourable fractionation pattern) are... 

Time-resolved fluorescence one laser, two detection techniques... 

Describe two detection methods used in ELISA. (2 marks)... 

The enzyme was unfolded by guanidine HC1 treatment through two detectable phases Phases 1 and 2 were observed by fluorescence spectroscopy derived from tryptophan residue.14 The fluorescence maximum moved gradually from 336 to 331 nm as the... 

The following two detection methods can be done in a working day with a detection limit of 10-100 (Xg. 

The difference in coordination chemistry is also reflected by the difference in the lipophilicity and solution properties. For example, 90Y-SQ169 exists in solution as a mixture of two detectable isomers (cis and trans isomers) as evi-... 

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