Femtomole range, sample concentrations

Considering sample concentrations in the picomole to femtomole range on the target and the ablated sample volume during MALDI, it can be estimated that only a few attomoles of the analyte are needed for informative MS analysis. 

The moles injected are determined from the sample size, concentration, and split ratio and are typically in the range of 1.0 femtomole for a high-capturing compound such as CCI4 with a K of 1011 L/mole. The molar response of a negative-ion mass spectrometer can be determined in the same manner, but the moles into the mass spectrometer must be estimated. 

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