Mass spectrometry incompatibilities with HPLC

Peak purity tests are used to demonstrate that an observed chromatographic peak is attributable to a single component. Mass spectrometry is the most sensitive and accurate technique to use for peak purity evaluation because of the specific information derived from the analysis. However, a good number of HPLC methods use mobile phase conditions that are incompatible with mass spectrometry detection. In this case, PDA spectrophotometers using peak purity algorithms may be used to support the specificity of the method. Almost all commercially available diode array detectors are equipped with proprietary software that will perform these calculations. Although this technique is more universal in application to HPLC methods, the data provided is neither particularly... 

When compared to other mass-sensitive detectors such as flame ionization (FID), refractive index (RI), and mass spectrometry (MS), the ELSD can detect analytes without interference from organic modifiers and additives. The use of organic solvents in FID limits usefulness due to an increase in baseline noise, and FID cannot be used with HPLC. RI detectors, in general, are less sensitive than other detectors and are incompatible with gradient elution. Although the MS can be used with modifier gradients, ionization efficiencies... 

In the past the efficient on-line characterization of flavor progenitors by mass spectrometry has been limited by the polar and labile character of these compounds. Combining HPLC with mass spectrometry could have been the method of choice for the analysis of glycoconjugates. But in order to transform molecules from solution to ions in the gas-phase one had to deal with three major incompatibilities (/) ... 

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