Creating Molecular Project Properties

Overview

Molecular project properties are designed to enable you to create your own molecular properties, as typically obtained from Gas Chromatography (GC) and Mass Spectrometry (MS) analysis, in p:IGI+. To define a molecular project property you need to provide very similar information to a standard project property. Molecular properties can only be of numerical type.

Usage: Data --> New project property... --> Molecular Numeric

How to use in practice

Creating molecular project properties

Creating molecular project properties works in a very similar manner to the creation of standard properties, however additional information must be provided for each of the molecular property indicators. The molecular property indicators are used to describe whether the compound concentration is measured as a height [h], area [a], concentration from height [ch], concentration from area [ca] and includes an unknown [un] indicator for data of unknown source.

For each indicator it is necessary to define the units to use. We strongly advise that for molecular data you retain the unit groups we provide by default. These are really the only sensible unit groups for their indicators. However it is reasonable to select the default unit, and change this if you wish for concentration measurements. By default we select parts per million (micrograms per gram) as the default units for concentrations. For heights and areas we only provide one unit, the count unit from the Unitless GC group. The unknown indicator uses the unknown unit, since it is very unlikely that the unit will be known. As shown in the above screenshot we attempt to detect when you are creating a property already in the property model, and provide a warning.

Note that equations can also be defined for molecular properties. If you create a ratio of two, or more, molecular properties you should select the "Property is a ratio quantity" checkbox. For a ratio molecular (or gas or standard) property the units for the property should be set to the Unitless unit group, and can then be any of the options within that group, but the Euclid (Euc) - standard non-dimensional value is probably the most common. See the image above for an example of how to create a new molecular ratio property. More information is given in the section on defining equations for project properties.

Using and sharing molecular project properties

Molecular project properties can be used and shared like any other project property; their definition will be 'carried' with any artefact in which they are used.