On-exchange experiments

Holding meetings on exchange experience gained in SFR operation and decommissioning ... 

Figure 14.6 The concept of the on-exchange experiments for the identification of the epitope using HX-MS. (a) On-solution (on-exchange in solution) and (b) on-column (on-exchange in column). See text for details. Reproduced from Ref [71], with kind permission from John Wiley Sons, Ltd.

Equilibrium exchange experiments. In this situation, the unidirectional flux of isotopically labelled glucose across the membrane is measured as a function of the glucose concentration, which is kept equal on both sides of the membrane. Because the unidirectional influx and efflux at any particular concentration are necessarily equal, the equilibrium-exchange (ee) flux is characterized by a single V ax value, and a single Km value. A . 

Experimental data are available using an ion-exchange resin catalyst based on batch experiments at 60°C10. These data are presented in Table 5.710. 

A fully automated system for performing detailed studies has been developed to improve the reproducibility and throughput (Fig. 12.2) [8]. It consists of two functional components a sample-deuteration device and a protein processing unit. The preparation operations (shown at the top of Fig. 12.2) are performed by two robotic arms equipped with low volume syringes and two temperature-controlled chambers, one held at 25 °C and the other held at 1 °C. To initiate the exchange experiment, a small amount of protein solution is mixed with a deuter-ated buffer and the mixture is then incubated for a programmed period of time in the temperature-controlled chamber. This on-exchanged sample is immediately transferred to the cold chamber where a quench solution is added to the mixture. 

Solvolysis was in some cases cairried out in the presence of an excess of methylcyclopentane to trap intermediate ions as fast as possible via hydride transfer. In other experiments the hydride donor was added ten minutes after solvolysis. The results of a series of exchange experiments on the butyl system are shown in Table 5. 

The first objective has been accomplished by the development of an HPLC procedure as reported by Spalik et al. ( 5) and GC/NPD procedures developed by Lemley and Zhong ( ). The second and third objectives are being accomplished by fundamental solution studies and reactive ion exchange experiments conducted in parallel. Lemley and Zhong (7) determined recently the solution kinetics data for base hydrolysis of aldicarb and its oxidative metabolites at ppm concentrations and for acid hydrolysis of aldicarb sulfone. They have since ( ) reported similar results for ppb solutions of aldicarb and its metabolites. In addition, the effect on base hydrolysis of temperature and chlorination was studied and the effect of using actual well water as compared to distilled water was determined. Similar base hydrolysis data for carbofuran, methomyl and oxamyl will be presented in this work. 

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