Detection window

Figure 4 Elements of a Crack Detection Window of an Image Processing Program...

The optimum gate width AT for a specific lifetime amounts to 2.5t. In Fig. 3.10 a typical F-x curve is shown for time domain lifetime detection with a variable number of time bins and a total detection window (sum of all the time bins/gate widths) of 10 ns (de Grauw and Gerritsen, 2001). The curves are representative for both TCSPC and TG operating in a high excitation frequency mode of... 

Fig. 3.10. Figure of merit curves for time domain lifetime detection with a variable number of gates. For all the curves the total detection window, the sum of all the gate widths, is 10 ns. 

Sintering of the packing materials to create the inlet end-frit at a distance representing the desired packed segment length followed by the removal of the polyimide coating from the detection window close to the outlet frit. 

Fig. 2.166. Separation of xanthomonasin-A and remaining Trp-P-2(NHOH) in the short-contact mode (a) and in the long-contact mode (b). (a) In the short-contact mode, the MEKC conditions were as follows capillary, 50 pm i.d. X 36 cm running solution, 10 mM SC solution in 25 mM phosphate buffer at pH 7 applied voltage, 15 kV temperature, 20°C detection, 264 nm concentration, O.lmM xanthomonasin A and O.lmM Trp-P-2(NHOH). (b) In the long-contact mode, the MEKC conditions were running solution, 10 mM SC solution in 25 mM phosphate buffer containing O.lmM xanthomonasin A at pH 7. The negative shift of the baseline (indicated by the arrow) shows that the zone of xanthomonasin-A passed the detection window. The other conditions are the same as those in the short-contact mode. Reprinted with permission from T. Watanabe el al. [338]...

FIGURE I 8 At the detection window of the capillary the polyimide layer of the capillary outer coating is burned. At this spot the capillary is extremely fragile and may break easily. 

Detection If a small capillary diameter is desired for efficiency purposes, the detection part of the capillary can be adapted for better detection sensitivity. Examples are the bubble cell capillary and the Z-cell. In the bubble cell capillary, the capillary diameter is enlarged at the detection window so that better concentration sensitivity is obtained. If you implement a bubble cell capillary in your pharmaceutical analysis method, it is important to test different batches. Test also whether you need a bubble cell capillary or whether you can gain similar sensitivity increase with a proper injection procedure. Also, check the effect of the bubble cell on band broadening. An approximately three-times sensitivity enhancement is possible. 

For the Z-cell, a special interface is constructed for the detection to take place in the length of the capillary instead of the diameter. Two different lengths of capillary with tapered ends on one side are connected with the interface. This takes some experience, so it is important to test putting the set together by different analysts, both experienced and inexperienced. The device is only useful if you have sufficient separation between the analytes of interest, since a longer plug is in the detection window. Consequently, if the analyte bands are simultaneously in the detection window, resolution is no longer observed. A sensitivity enhancement of a factor 10 is possible. 

Since CE is an on-column detection technique, analytes migrate with different velocities through the detection window. Thus, slower migrating compounds will have the same peak height but a larger peak area than faster migrating compounds. Therefore, it is common to work with corrected peak areas, i.e., peak area divided by migration time. The work on a racemic mixture of enantiomers demonstrates the importance of this correction. 

Different types of CE instruments have different thermostating systems, have different detectors, use capillary of different lengths, have detection windows at different distances from the injection point, and have different injectors. Thus, additional tests may be required after a method transfer. 

PotymnkJe removed vvnh coTK ammonia to provide detection window... 

Fig. 10 ACE using an etched capillary with heparin bound, (a) SLPI concentration, 10 mg/mL. ACE condition etched capillary, 75-/rm ID X 55 cm (47 cm from injection to detection window), heparin bound via silane spacer. Injection mode gravity, height 55 cm, time 15 s. Washing and elution mode pressure injection, 2 psi, 300 s. Buffer A, 25 mM sodium phosphate, pH 7.4 buffer B, buffer and 1.0 M NaCl. Detection wavelength, 220 nm. (b) ATIII concentration, 4.5 mg/mL. (c) Bovine serum albumin, 0.3 mg/mL. (From Ref. 85.)... 

The time required by a given analyte to migrate under the sole influence of the applied electric field across the capillary tube from the injection end of the capillary to the detection windows (migration distance) is defined as the migration time (tj and, similarly as the retention time in HPLC, is used for identification of sample components. It is given by... 

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