Quickly extract the differences between two samples, such as good or defective products, differences in origin, differences in manufacturing methods, etc!
Work Screen for Difference Analysis Results
msFineAnalysis IQ performs difference analysis using statistical hypothesis testing. The statistical hypothesis test uses GC/EI data (two samples measured in replicates, e.g., n=3 or n=5) to determine if there is “repeatability” and “difference” in the detected compounds between the samples. After classification of compounds that are characteristic of each sample and those that are common to all samples, integrated analysis using GC/EI and SI data is performed automatically.
Volcano plot
In the volcano plot, each circle corresponds to a single compound, and the size of the circle reflects the peak area. The horizontal and vertical axes are shown below:
【Horizontal axis】
Logarithm of the intensity ratio between two samples (Fold-change)
The larger the absolute value, the greater the intensity ratio between samples.
【Vertical axis】
Negative value of logarithm of p-value the larger the value, the higher the reproducibility.
A volcano plot enables intuitive visualization of both differential components between samples and their reproducibility.
Difference analysis of chocolates with different cacao content using HS-SPME-GC-QMS (MSTips No. 438)
In each sample, compounds found in chocolate aroma, such as aldehydes, esters, carboxylic acids and nitrogen-containing pyrazines, were detected.
Compound ID:032 with the highest intensity at approximately 95% cacao content was estimated to be pyrazine, tetramethyl-. Pyrazine, tetramethyl- is an aroma produced by roasting cacao, and it is suggested that it is strongly detected in this sample with a higher cacao content. The compound eluted at a time close to that of a common component, acetic acid, between the two samples. However, it could be detected by deconvolution peak detection.
application details:
MSTips No. 438Difference analysis of water-based inks of different colors (cyan and magenta) (MSTips No. 396)
Compounds found specifically in the cyan and magenta are in the left and right regions, respectively, of the volcano plot. Although quantitatively smaller than common components such as water and isopropyl alcohol in the center, we found that ethanol, 2,2'-oxybis- (diethylene glycol) and four other compounds were specifically present in cyan, as opposed to caprolactam, which is specifically present in magenta.
application details:
MSTips No. 396