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Available Analysis Functions

This topic covers the basic analysis functions in TRIOS software. The list of available functions varies based on the type of data obtained. For additional information, refer to Analysis Models and/or Basic Steps to Analyzing Data Help topics.

Click an analysis function below for more information. Once you have completed an analysis, refer to Basic Steps for Analyzing Data to edit the analysis and evaluate the impact on the calculated parameters.

Performing an Analysis

Click on the desired curve to analyze.
Select the desired analysis from the Analysis > Function menu.
Click Analyzeto execute the analysis.

See Also

Basic Steps to Analyzing Data

Signal Min/Max

Use the Signal min option to determine the minimum measured value between two selected points on a curve. Use the Signal max option to determine the maximum measured value between two selected points on a curve. See Basic Steps to Analyzing Data to select associated analysis options before beginning.

NOTE: Peak Max and Signal Max analyses report the same result if the baseline is perfectly horizontal (the Y-axis values of the start and stop limits are the same).

Signal Change

Use the Signal change option to measured the change in the measured values between two defined points of data. A horizontal line is drawn from your selected start point to a vertical line drawn from your selected stop point. The difference between these points is reported. See Basic Steps to Analyzing Data to select associated analysis options before beginning.

Peak Height

Use the Peak height option to determine the point of maximum deviation from a linear baseline drawn between two points on the curve. After you select the start and stop limits to define the baseline, the program calculates and reports the height of the peak. See Basic Steps to Analyzing Data to select associated analysis options before beginning.

NOTE: Peak Max and Signal Max analyses report the same result if the baseline is perfectly horizontal (the Y-axis values of the start and stop limits are the same).

Peak Integration

Use the Peak Integration options to calculate and report the following:

Peak onset time or temperature
Peak maximum time or temperature
Peak area
Extrapolated peak

The peak is integrated with respect to time between the designated start and stop baseline limits. You select type of baseline used from the Analysis option (see below). See Basic Steps to Analyzing Data to select associated analysis options before beginning.

NOTE: To perform an Peak Integration analysis with divided areas, see TRIOS software Help topic Peak Integration – Divide Peak.

Peak Integration Analysis Options

Baseline Type – Linear

Linear Type

Double point: Baseline is determined by two limits that define the transition range on either side
Horizontal (from left): Baseline is determine by a linear extrapolation from a point chosen on the left side of the peak
Tangent (from left): Baseline is determine by a tangent line drawn from a point chosen on the left side of the peak
Manual tangent (from left): Baseline is determine by a tangent line defined by two points chosen on the left side of the peak
Horizontal (from right): Baseline is determine by a linear extrapolation from a point chosen on the right side of the peak
Tangent (from right): Baseline is determine by a tangent line drawn from a point chosen on the right side of the peak
Manual tangent (from right): Baseline is determine by a tangent line defined by two points chosen on the right of the peak

Onset Type

Tangent: Uses the selected point to calculate a tangent line
Manual tangent: Allows you to define the start and stop limits for the inflection tangent line
Inflection: Automatically calculates the onset line as the tangent to the curve at the inflection point (defined as the steepest 1/10 portion of the curve from peak start to peak max).

Baseline Type – Sigmoidal

A sigmoidal baseline is an s-shaped line that changes in level and/or slope before or after a peak. It is used to compensate for the change in baseline that occurs during a transition; the baseline is adjusted for the fraction reacted (alpha) versus time.

A sigmoidal baseline initially is calculated as a straight line between the selected limits. It is then recalculated for each data point between the limits as the weighted average between the projected horizontal or tangent baselines at peak start and end. The weighting factors for a given point are: (1) one minus alpha times the initial baseline and (2) alpha times the final baseline. The area is then recalculated with the new baseline. If the new area differs from the previous area by more than one percent, the area is recalculated and the sigmoidal curve shifted repeatedly until two consecutive calculations of the area differ by no more than one percent. If the baseline fails to converge within ten iterations, the calculation is aborted.

Left/Right Limits

Horizontal: To calculate a sigmoidal horizontal baseline, two lines are drawn between the selected limits, then a sigmoidal curve is drawn with its midpoint halfway between the horizontals. This baseline type is often used when a glass transition and cure overlap.
Tangent: To calculate a sigmoidal tangent baseline, two tangent lines are fit within the selected limits on each side of the transition. A sigmoidal curve then joins the tangent lines.
Manual tangent: The baselines are determined by tangent lines defined by the two points chosen on each side of the peak. A sigmoidal curve then joins the tangent lines.

Onset Type

Tangent: Uses the selected point to calculate a tangent line
Manual tangent: Allows you to define the start and stop limits for the inflection tangent line
Inflection: Automatically calculates the onset line as the line tangent to the curve at the inflection point (defined as the steepest 1/10 portion of the curve from peak start to peak max).

Peak Integration for Instruments Other than DSC

The peak area is normalized for other instrument types only when the signal being integrated is normalized.

NOTE: For these instruments, the Normalized Area option has no effect.

The peak onset is calculated as the intersection of the onset tangent line with the calculated baseline. The onset tangent line is fit to the current X-axis type, and can be selected in automatic mode (the default condition) or manual mode (selected using the Analysis Options > Peak Integration page).

NOTE: The onset line and onset point are not displayed if the axis scaling is log.
NOTE: Use caution when integrating peaks that have been rotated. For more information, see Using Analysis Tools.

If the measured data includes superheating or supercooling (temperature hysteresis of more than 0.25°C), the onset point is determined at the superheating or supercooling point. Superheating and supercooling are relevant only if the X-axis is temperature.

Use the Onset point analysis option to determine the temperature at which a change in the slope of the curve occurs (i.e., the onset point of a transition). The onset point is defined as the intersection of an initial tangent line with a final tangent line.

Best Fit

Use the Best Fit option to generate two labels for flow curves: one with R2 values for all the applicable models, and one complete analysis for the one with the best value. From the Analysis menu, select Best fit flow from the Function toolbar.