Blank Subtraction

When analyzing a sample, the obtained signal may be caused by analytes as well as by dilution solvents, mobile phases, additives etc. Use the blank subtraction to receive a clean chromatogram with contribution of the analytes only.

Blank signals can origin from:

• a blank sample within a sequence

• a blank sample outside of the sequence (for example, a single run)

The new signal is calculated by subtracting the blank signal:

New signal = sample signal - blank signal

For extracted chromatograms using a specific wavelength:

New signal = sample signal at wavelength - blank signal at wavelength

For extracted chromatograms using a specific m/z:

New signal = sample signal at m/z - blank signal at m/z

If a blank and a sample have different data rates, the data rate of the blank is adjusted. Data points are removed or created by interpolation (linear interpolation for MS data, spline interpolation for non-MS data).

If the run time of the sample is longer than the run time of the blank, the new signal will contain corrected and not corrected data points.