Advantages Of Photodiode Array Detection - Thermo Scientific Dionex ICS Series Operator's Manual

1.2.1

Advantages of Photodiode Array Detection

Photodiode array detectors are useful in both research and quality
assurance laboratories. In the research laboratory, the photodiode array
detector provides the analyst with a variety of approaches to the analysis.
In the quality assurance laboratory, the photodiode array detector provides
several results from a single analysis, thereby increasing the throughput
of the HPLC.
Photodiode array detection offers the following advantages:
•
Peak measurement at all wavelengths
In methods development, detailed information about the detector
conditions required for the analysis may not be known. When a
variable wavelength detector is used, a sample must often be injected
several times, with varying wavelengths, to ensure that all peaks are
detected. When a photodiode array detector is used, a wavelength
range can be programmed and all compounds that absorb within this
range can be detected in a single analysis.
•
Determination of the correct wavelengths in one analysis
After all peaks have been detected, the maximum absorbance
wavelength for each peak can be determined. A photodiode array
detector can collect spectra of each peak, after which the detector
software can calculate the absorbance maximum.
•
Detection of multiple wavelengths
A photodiode array detector can monitor a sample at more than one
wavelength. This is especially useful when the wavelength maxima of
the analytes are different. Wavelengths can be selected to analyze
each compound at its highest sensitivity.
•
Peak purity analysis
It is difficult to determine component purity from a chromatogram.
However, a photodiode array detector can analyze peak purity by
comparing spectra within a peak. The better the spectra match, the
higher the possibility that the peak is pure.
•
Positive peak identification
In liquid chromatography, peak identification is usually based on
relative retention times. When a photodiode array detector is used,
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1 • Introduction
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