Page 461 - Tandem Techniques
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conjunction with the solenoid type coil shown in Figure 11.6A is becoming the more popular
combination for LC/NMR tandem instruments.
Figure 11.6
Probe Characteristics for LC/NMR Operation.
Behnke et al. [4] has investigated the different interfaces that have been proposed for LC/NMR tandem
systems and reported on their advantages and disadvantages. In the past, on-line LC/NMR
measurements have been made using 4.6 mm I.D. columns in conjunction with relatively large probe
cells, which had a detection limit of about 5 nmol, when used with a 600 MHz spectrometer and a line
width of 102 Hz. The major problem with such systems are, as already discussed, the elaborate solvent
signal suppression that is necessary as part of the spectrum is masked by the solvent. Employing
supercritical fluid chromatography allows the use of
