Efficacy of planar chromatography coupled to (tandem) mass spectrometry for employment in trace analysis

HPTLC/MS by a plunger-based extraction device was shown to be an appropriate technique for quantitative planar chromatography, even in trace analysis. Reproducible extraction from silica gel phases in the lower-pg range distinguishes this technique from other approaches. Repeatability of the MS signal showed a mean RSD of 12.5% for the example of Harman, a heterocyclic aromatic amine. Analytical response within a plate and over various plates/days showed determination coefficients of 0.9915 and 0.9488, respectively. Limit of detection (LOD) by a single quadrupole was better than 40 pg and limit of quantitation (LOQ) by a tandem mass spectrometer better than 20 pg. LOQ/LOD obtained were of similar magnitude as reported for HPLC/MS methods, however, this order of sensitivity was shown for the first time in the field of HPTLC/electrospray ionization MS.