91
increasing concentrations/amounts of the standard reference material. Note that the
relationship does not fit the ideal or predicted linear relationship. However, matching fluctuations are observed in the measured ion current (i.e., peak height) for the
internal standard added at a fixed amount to each calibration sample (i.e., right hand
panel). In this way, fluctuations in the measured signal over time/across samples are
“normalized”. Consequently, when the response ratio, Ra/Ris, is determined and
plotted against the amount of standard/calibrator, precise and absolute quantification of analyte levels can be determined by DART/DESI-MS and similar strategies.
5.5 Conclusions
DART-MS, DESI-MS and related direct analysis strategies are powerful tools for
sample analysis, analyte identification and quantification. These ionization strategies can circumvent some of the practical complications of more convention
approaches to mass spectrometric analysis, most notably, the complexities of
Fig. 5.4 utility of an internal standard in quantitative applications. The incorporation of a standard
curve allows absolute quantification. This figure (i.e., left hand panel) shows the measured ion current (e.g., measured peak height) for increasing concentrations/ amounts of the standard reference
material. Note that the relationship does not fit the ideal or predicted linear relationship. However,
matching fluctuations are observed in the measured ion current (i.e., peak height) for the internal
standard added at a fixed amount to each calibration sample (i.e., right hand panel). In this way,
fluctuations in the measured signal over time/across samples are “normalized”. Consequently,
when the response ratio, Ra/Ris, is determined and plotted against the amount of standard/calibrator, precise and absolute quantification of analyte levels can be determined by DART/DESI-MS
and similar strategies
Measured Response Analyte
Measured Response Int. Std.
Run # [Standard]
Amount of Analyte
Added to Standard
5 Direct Mass Spectrometry as a Practical Analytical Strategy for High Speed, High…
increasing concentrations/amounts of the standard reference material. Note that the
relationship does not fit the ideal or predicted linear relationship. However, matching fluctuations are observed in the measured ion current (i.e., peak height) for the
internal standard added at a fixed amount to each calibration sample (i.e., right hand
panel). In this way, fluctuations in the measured signal over time/across samples are
“normalized”. Consequently, when the response ratio, Ra/Ris, is determined and
plotted against the amount of standard/calibrator, precise and absolute quantification of analyte levels can be determined by DART/DESI-MS and similar strategies.
5.5 Conclusions
DART-MS, DESI-MS and related direct analysis strategies are powerful tools for
sample analysis, analyte identification and quantification. These ionization strategies can circumvent some of the practical complications of more convention
approaches to mass spectrometric analysis, most notably, the complexities of
Fig. 5.4 utility of an internal standard in quantitative applications. The incorporation of a standard
curve allows absolute quantification. This figure (i.e., left hand panel) shows the measured ion current (e.g., measured peak height) for increasing concentrations/ amounts of the standard reference
material. Note that the relationship does not fit the ideal or predicted linear relationship. However,
matching fluctuations are observed in the measured ion current (i.e., peak height) for the internal
standard added at a fixed amount to each calibration sample (i.e., right hand panel). In this way,
fluctuations in the measured signal over time/across samples are “normalized”. Consequently,
when the response ratio, Ra/Ris, is determined and plotted against the amount of standard/calibrator, precise and absolute quantification of analyte levels can be determined by DART/DESI-MS
and similar strategies
Measured Response Analyte
Measured Response Int. Std.
Run # [Standard]
Amount of Analyte
Added to Standard
5 Direct Mass Spectrometry as a Practical Analytical Strategy for High Speed, High…