/Isopairs, however, can be used to capture the effect of drift across the mass spectra so that it can be removed. Isolock determines the optimal mass drift value as that which maximizes isopairs and all mass values can then be adjusted by this value. After alignment of spectra via isoLock, spectra from hundreds to thousands of samples can be pooled into a single merged mass spectra in which signal to noise ratios are dramatically enhanced.