Variations in the composition of brewed coffee as a function of brewing time were monitored using gas chromatography-mass spectrometry. Batches of coffee were produced using flow rates of SO-500 mL/min, which resulted in brewtimes of 4.42-31.07 min. While most components increased in concentration with longer brewing times, several showed significant losses beyond 8 min, indicating an optimum brewtime of 7-9 min.

No abstract

Principal component analysis has been evaluated as a digital filter to Improve the overall quality of gas chromatography/ mass spectrometry (GC/MS) data sets. Data are Initially read Into a matrix, scaled, and then processed by using the NI-PALS algorithm, which Is used to separate signal from the matrix. A new matrix Is then reconstructed as the difference between the original and residual matrices, which Is then rescaled and a new data file created. By use of a six-component solvent mixture with samples of from 0.5 to 150 pg of each component, significant Improvements In mass spectral quality and spectral matches were observed. Signal to noise was improved by a factor of from 2 to 100 due to improved Integration. Linearity and precision of chromatographic data were also improved.

No abstract