Page 287 - Tandem Techniques
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Page 271
In general, fluorescence detectors are about 100 times more sensitive than the UV absorbance systems,
and thus can detect substances present in the sub pico-gram range. The sensitivity of the HP tandem
instrument is clearly demonstrated by the results shown in Figure 7.12.
Figure 7.12
Demonstration of the Sensitivity of the HP LC/FL
Tandem Instrument to Anthracene
Courtesy of the Hewlett Packard Corporation
The sample mixture contained a mixture of benzo(a)pyrene and anthracene. An amplified section of the
base line (included in Figure 7.12) shows the noise to be about 0.2 mv. Consequently, the minimum
detectable mass is quoted as 0.75 pg for benzo(a)pyrene, and 0.13 pg for anthracene. Unfortunately, the
more useful specification, the minimum detectable concentration, was not reported and is difficult to
estimate with any degree of accuracy from the chromatogram.
The greater sensitivity provided by fluorescence, over that provided by UV absorption, is not the only
advantage of monitoring a separation by
