ABSTRACT
It should be pointed out that, although tandem systems are very effective and extremely exciting to operate, they are quite complex and also very expensive. If the analysis is not repetitive, there is adequate sample, and only one substance in the mixture being chromatographed is of consequence, then an off-line spectroscopic examination may be the more practical alternative. For single solutes it may be nearly as fast to collect the component as it is eluted and examine it spectroscopically off line, as it would be to employ a tandem system. In fact, it is probable that better quality spectra will be obtained and the solute identity confirmed with greater confidence. The off-line approach, however, is not practical for multi-component mixtures or for repetitive analyses where the results may be required for forensic purposes.
