Elution Emitter

The short lived positron-emitter Rb-82 (t 1/2=1.26m) has potential application in cardiovascular diagnostic nuclear medicine. A generator system containing the parent Sr-82 has been developed that will provide an eluate of Rb-82 suitable for direct infusion. The Rb-82 is eluted by a syringe pump from a hydrous stannic oxide column in a continuous stream of physiological saline solution. The rate of elution (infusion) can be controlled from 10 to 100 ml/ min. At elution rates of 25, 50, and 75 ml/min,... 

The emitting species for sulfur compounds is excited S2. The lambda maximum for emission of excited S2 is approximately 394 nm. The emitter for phosphorus compounds in the flame is excited HPO with a lambda maximum equal to doublet 510-526 nm. In order to detect one or the other family of compounds selectively as it elutes from the GC column, the suitable band-pass filter should be placed between the flame and the photomultiplier tube to isolate the appropriate emission band. In addition, a thermal infrared filter is mounted between the flame and the photomultiplier tube to isolate only the visible and UV radiation emitted by the flame. Without this filter, the large amounts of infrared radiation emitted by the combustion reaction of the flame would heat up the photomultiplier tube, thus increasing its background signal. 

Actinides, unlike lanthanides, are a emitters. Tests made with 243Am, 241Am, and 244Cm, which have a radiation intensities (or a decay constants) in the ratio 1 17 435, gave very similar results in regard to both target elution and product yield. Therefore, if a radiation is responsible for the difference, the effect is independent of a intensity. 

The separation column effluent is divided into about 15 fractions that are collected in small (250-mL) polyethylene bottles. The volume collected in each bottle is determined by the appearance of the alpha-emitting elements in the column effluent solution as indicated by the response from the flowthrough alpha detector a typical response curve is shown in Fig. 2. Normally/ two einsteinium fractions/ two intermediate fractions/ and three californium fractions are collected. The intermediate fractions are taken when the valley between the einsteinium and californium peaks occurs on the response curve and usually contain less than 5% of each element. Sometimes the alpha trace will show a small fermium peak just ahead of the einsteinium/ but usually there is not enough fermium alpha to make a response and the fermium is assumed to be in one or both of the two fractions taken just prior to the einsteinium. The berkelium is primarily a beta emitter and is not detected by either the alpha or neutron detectors thus, three fractions are usually taken after the californium alpha peak to isolate the berkelium. If there is a significant amount of 244Cm he feed (milligram quantities)/ the alpha trace will show a third major peak when americium and curium are eluted at the end of the run. 

The third means of radionuclide production involves target irradiation by ions accelerated in a cyclotron. One example of this approach is provided by the production of Ge, which decays with a 280 day half-life to the positron emitter Ga. Proton irradiation of Ga produces Ge in a (p,2n) reaction. After dissolution of the target material a solution of the Ge product in concentrated HCl is prepared and adsorbed on an alumina column which has been pre-equilibrated with 0.005 M EDTA (ethylenediaminetetraacetate) solution. The Ga daughter may then be eluted using an EDTA solution in a system which provides the basis of a Ga generator. Cyclotron production of radionuclides is expensive compared with reactor irradiations, but higher specific activities are possible than with the neutron capture process. Also, radionuclides with particularly useful properties, and which cannot be obtained from a reactor, may be prepared by cyclotron irradiation. In one example, cyclotron produced Fe, a positron emitter, may be used for bone marrow imaging while reactor produced Fe, a /3-emitter, is unsuitable. " ... 

This nib system connected to a capillary was then placed at the outlet of a nanoLC column for on-line analysis after a separation step.26 The column was monitored from a nanoLC setup (LC Packings-Dionex, The Netherlands). An amount of 1 pL of sample was injected (Famos injection system, LC Packings-Dionex) onto a commercial nanocolumn (PepMap, 75 pm i.d.) and eluted in gradient conditions at a flow-rate of lOOnLmin 1 (Utlimate micro pump and accurate stream splitter, LC Packings-Dionex) using solvent mixtures based on AcCN and deionized water (solvent A AcCN H20 5 95 solvent B AcCN-H20 95 5) acidified with 0.1% TFA. Ionization HV was 1.5kV, as typically used for a standard emitter tip. The sample used for this test is a commercial cyctochrome c digest at a concentration of 800 nM. The spray was seen to be stable for several hours (several nanoLC runs) as expected with a standard emitter tip. The analysis of the solution eluted from the column was possible and the same as for routine conditions. 

Electron capture detector ECD GC detector that uses a foil as a (3-emitter, the output signal depends on the resulting electron flux between the foil and collector electrode, elution of compounds containing atoms with a high electron affinity causes a decrease in the flux and therefore in the signal, has high sensitivity (10 to 10 aromatic compounds. 

Figure 5.4-7. Schematic workflow of MuDPIT. The MuDPIT technique represents a relative simple setup compared with the other MDLC approaches. For the complete system, a single nano-gradient pump and an optional autosampler is required. The two-dimensional separation takes place in the biphasic ESI-Tip emitter, which results in a near dead-volume-free solution. Peptides are eluted from the strong cation exchange phase (SCX) with salt-plugs that are injected by the autosampler. Afterward the trapped peptides are separated with a linear gradient and directly sprayed into the mass spectrometer.

A sample of the praseodymium group (praseodymium, neodymium, and element 61 most of the cerium, samarium, europium, and yttrium fission products had been removed, cerium by ceric iodate precipitations and the others by potassium carbonate digestions) was absorbed on an Amberlite IR-1 column. The elution curve is shown in Fig. 14.1. The soft P emitter (now known to be 2.62-year see Table 14.2) appeared in the position expected (by... 

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