Local minimum resolver (Other data)

Info

To process data from other detectors, the Other detector service of mzmine is required. This feature is included in the mzmine PRO subscription. Academic program and other users can reach out to inquire access options.

The resolver detects individual chromatographic peaks in a trace and resolves them into individual features (see trace types).

At the same time, the area percentage is calculated in reference to the preprocessed trace.

Parameters

Trace selection

Select the specific traces you want to resolve. Typically, it is not necessary to resolve all existing traces, but only the ones you want to correlate with the MS, e.g., the UV (=Absorption) traces

For a detailed description of all sub-parameters see trace selection parameter.

Chromatographic threshold

This filter assumes that most of the data points contain no signals to remove unnecessary noise.

Specify the percentage of data points in the trace to be removed before local minima search. This represents an important filter for noisy chromatogram and significantly reduces the processing time. The algorithm finds the intensity value (threshold) that leaves the specified percentage of data points in the trace below the given value. All such data points are removed.

The typical values for data from other detectors may be significantly different from from MS data. E.g., MS data may require 85%, whereas other data may require lower values such as 50%.

Minimum search range

Size of the RT window examined for local minimum search. An overly narrow search range can cause peak edges to be cut off, whereas a too wide search ranges might lead to an incomplete resolution of narrowly eluting peaks (see example below).

Minimum absolute height

Minimum absolute intensity a peak needs to reach to be retained as a feature.

Minimum relative height

Minimum relative intensity (with respect to the highest data point in the trace) a peak needs to reach to be retained as a feature. This parameter can be used in combination with the Minimum absolute height setting as to filter the resolved features to be retained.

Min ratio of peak top/edge

Minimum ratio between the intensity of the highest (apex) and side (left and right 'edges') points of a peak, to retain it as a feature. The peak edges have to be X times less intense than the peak apex for the feature to be retained.

This parameter can best be optimized using the Show preview option. We recommend values between 1.7 (not baseline separated) and 2 to start the optimisation.

Peak duration range

Range of acceptable peak length expressed in minutes (RT dimension). This parameter can be used to filter out noisy features based on their overly short (or long) duration.

Minimum scans (data points)

Minimum number of data points a resolved peak needs to have to be considered valid and retained as a feature. This parameter can be used along with the Peak duration range setting as peak duration constraint to filter out noisy features.