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Tetracycline |
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Introduction The figure below shows the separation of a mixture of tetracycline analogs analyzed on the PDR-Chiral Detector. The separation clearly shows the five expected peaks.
In the chromatogram below, we see a sample of the same mix but at a different concentration and without filtration.
The next chromatogram shows a sample of the same mixture after filtration through a 0.4 micron nylon filter. Note that one of the analogs has now degraded into two components and both of which are optically active. Among other things, this suggests the detector’s usefulness in quality assurance applications. Comparing this chromatogram and the chromatogram of the unfiltered mix (above) clearly shows that the filtration does not affect tetracycline compounds. In comparing peak heights, we see that they almost fall on top of each other. Thus, we can use the filtration step in the rapid preparation of contaminated milk.
The chromatogram below shows the same standard (with degraded component) spiked with a milk sample. The contaminated milk was mixed 1:1 with mobile phase, and then filtered through the 0.4 micron filter. The filtrate was injected directly into the HPLC. Total preparation time was less than one minute. Total analysis time was less than nine minutes for all six components. We spiked at two different levels with recoveries of > 90% by this method at both levels.
The figure below graphically shows the calibration curve for the 5 tetracycline analogs. Correlation coefficients varied from 0.0997 to 0.9999 using the PDR-Chiral Detector for detection.
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