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...associated with chromatograms being incorrectly labelled according to sample type.
Occasionally, the procedure for resetting a RITS system by simultaneously powering down all of its separate components was not rigorously followed, and the data recording system would lose track of the sample type being injected onto the columns. This would cause an anomalous phase shift between the actual sampling sequence and the sampling sequence assumed by the data recording system as it assigned sample type labels to the chromatograms. This problem was detected by plotting ratios of nearby environmental and calibration samples in the areas/heights database and checking for anomalous step jumps in the times series. Many such episodes have been corrected.
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