Trap used

Another powerftil class of instmnientation used to study ion-molecule reactivity is trapping devices. Traps use electric and magnetic fields to store ions for an appreciable length of time, ranging from milliseconds to thousands of seconds. Generally, these devices mn at low pressure and thus can be used to obtain data at pressures well below the range in which flow tubes operate. 

Pritchard D E, Raab E L, Bagnato V, Wieman C E and Watts R N 1986 Light traps using spontaneous forces Phys.Rev.Lett. 57 310-13... 

The use of polar solvents, such as /V, /V- dim ethyl fo rm am i de [68-12-2] is noted to result in extensive trimer formation. However, if the isocyanate is trapped using compounds such as alcohols, carboxyUc acids, and amines which contain active hydrogen, high yields are obtained (93). 

Fig. A3.12. (a) Rotary evaporator (Buchler Instruments) (b) Trap used with rotary evaporator.

The steam traps (used to drain water from a separator where this is fitted, perhaps to deal with carry-over from a boiler, or to drain condensate from collecting legs at intervals of not more than, say, 50 meters along the steam line) clearly must have adequate capacity. For the separator at the boiler off-take or at a header supplied from the boiler(s) and itself supplying the steam mains, it may be necessary to have capacity in the trap(s) of 10 per cent or even more of the boiler rating. On the steam lines themselves it is rare for a trap larger than inch or 15 mm size to be needed. Very often, the low-capacity versions of the i-inch steam trap are more than adequate. 

Radical traps used for the study of radical monomer reactions should meet a number of criteria ... 

There have apparently been no recent developments in reagents for desulphurizing sulphoxides that use pentavalent phosphorus compounds. Reagents that were reviewed in 1984 include phosphorus pentasulphide, thiophosphoryl bromide, Lawesson s reagent (1), and phosphorus pentachloride in the presence of a trap for CD ions. The traps used included an enamine or an N, JV-dialkylaniline. Presumably, the net effect of this reaction is to generate phosphorus trichloride in situ. The three thiophosphorus reagents obviously function because the P=S bond is some 150 kJ moD weaker than the P=0 bond . 

In the reaction flask is placed 600 cc. of commercial ter/.-butyl alcohol (Note 1), and the air in the flask is displaced by dry nitrogen gas. Then 29 g. (0.75 gram atom) of metallic potassium is added, in portions, to the alcohol. The mixture is heated on a water bath until all the potassium has dissolved, and then 68 g. (0.5 mole) of o-formotoluide (Note 2) is added and brought into solution. The condenser is set for distillation with a filter flask as the receiver this flask is protected from the air by connecting it to the trap used in the initial operation. The reaction flask is... 

Nickel Nickel converted to Ni(CO)4 by sodium borohydride. Cold trapped using liquid nitrogen AAS with quartz tube burner Sub-ng [524]... 

Tona, M. Kimura, M., Parallel plate ion trap useful for optical studies of microparticles, Rev. Sci. Instrum. 2004, 75, 2276 2279... 

The ladder polysilanes also show interesting photochemistry on irradiation with a high-pressure mercury lamp, the tricyclic ladder extruded the transient intermediate four-membered cyclic disilene which could be trapped using methanol, 1,3-butadiene, and anthracene, as shown in Scheme 38. 

Table 11 summarizes results of spin trapping experiments where PBN-Nu and other ST-Nu" systems have been oxidized anodically at platinum. Originally, all the reactions were suggested to proceed via Nu radicals (Janzen et al., 1980 Walter et al., 1982), but the fact that PBN is oxidized at a lower potential than Cl-, CNO and CN- (Tables 1 and 5) clearly shows that the faster electrochemical process must be PBN— PBN + at the potentials employed. On the other hand, azide ion is oxidized in a faster reaction than any of the spin traps used and thus azide radical is implicated as being trapped. The Cr 4MePyPBN [17] system is a case where possibly Cl is involved in view of the high pa of this spin trap. 

Fig. 38 The mechanism by which an essential Lys residue in the antibody combining site is trapped using the 1,3-diketone [117] to form the covalently linked vinylogous...

To recover part of the excess pivalaldehyde, the material that was collected In the cooling trap used with the rotary evaporator and with the Kugelrohr oven can be distilled over a 35-cm Vigreux column this yielded 150 mL of recovered pivalaldehyde. 

Kaiser, R.E., Jr. Louris, J.N. Amy, J.W. Cooks, R.G. Extending the Mass Range of the Quadrupole Ion Trap Using Axial Modulation. Rapid Commun. Mass Spectrom. 1989, 5, 225-229. 

Lord et al. analyzed a mixture of steroids by CEC-ESI/MS and interfaced externally tapered CEC columns in both sheathless and sheath-flow arrangement. Sensitivity was found 20-fold higher in the sheathless configuration. The same conclusion was drawn by Warriner et ah, who evaluated CEC-nanospray/MS vs. CEC-microspray/MS with an ion trap using five corticosteroids. Cahours et al. used CEC-ESI/MS for a drug metabolism study and obtained a simultaneous baseline separation of flunitrazepam and its major metabolites. For CEC-ESI/MS coupling, the commercially available packed-CEC column was connected... 

Hercules trap analychem Water-measuring liquid trap used in aquametry when the material collected is heavier than water. h3r ky3,lez, trap ... 

Also recognized was the flexibility of such composites, the good adhesion with the carbon material and the versatility and easiness for a wide range of (bio)molecule trapping using a simple phase-inversion process for its fabrication. These CNT/PSf... 

The electric mass filter is the basis for the electrodynamic trap used for studies of the spectroscopy of atomic ions that earned Paul and Dehmelt the 1989 Nobel Prize in Physics. A wide variety of electrode configurations can be used to trap particles, and a particularly simple design was proposed by Straubel (1956). His dc electrodes were flat plates, and the ac electrode was a simple torus or washer placed at the midplane between the endplates. 

Figure 6.42 Single trap using different SPE phases for a steroid-type drug. 10 ig of hydrocortisone per injection, 2-mm SPE cartridges, 600 MHz, 3-mm z-gradient LC-SEI probe with an active volume of 60 pi, 512 transients.

G. BrIx, M.E. Bellemann, L. Gerlach, U. Haberkorn, Direct detection of Intratumoral 5-fluorouracll trapping using metabolic F-19 MR Imaging, Magn. Reson. Imaging 17 (1999) 151-155. 

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