Here I have developed an excel file tool for aiding the process of identifying insect cuticular hydrocarbons (CHC). The Excel file is divided in three pages, CHC-Identification, Carlson(1998)-methyl alkanes, and post-DMDS.

The CHC-Identification page is the main tool, it relies on several formulas, conditional formatting, and data validation settings to display/indicate the user the total mass diagnostic ions (Tm), as well as the fragmentation diagnostic ions of hydrocarbons with specified molecular traits (e.g. chain length). It can also indicate the position of methylation(s) for mono-, di-, and trimethyl-branched alkanes of a given chain length, if the theoretical fragmentation ions are provided by the user.

The Carlson(1998)-methyl alkanes displays two figures on the elution pattern of mono-, di-, tri- and tetramethyl-branched alkanes of the same chain length (33 carbons), which have been taken from Carlson et. al (1998) paper (The link to the paper is included in the page as source). These figures are helpful in the process of identifying methyl-branched alkanes, and complementary to the CHC-identification tool of the first page.

The Post-DMDS page is to be used, as its name suggests, after a DMDS derivatization. This page is empty, but the plan is to set it similarly to the first page, its purpose would be aiding to determine the position of unsaturation(s) in the hydrocarbon chain lengths of alkenes (maybe also alkadienes) which requires the derivatization of the sample.

When you open the XLSX file at first, you get a message asking to open it as a read-Only file. Accept this, in the Read-Only mode you can still edit the data input cells to use the tool, but no modification will be saved, so you cannot alter the functioning of the formulas and settings in which the toos relies.

Note: Here is assumed that you will be using Microsoft office software (i.e. Excel) to operate the XLSX tool.

After you open the file you will see the first page, which is called CHC-Identification. Here you can see some explanatory text and several tables, with different types of cells (regarding their color).

The two type of cells are the information display cells (yellow/dark purple) and data input cells (blue). The information display cells, as their name indicates, display information in response to the input you provide on the data input cells. They contain formulas that operate with the input provided in the corresponding input cell(s), and due to a conditional formatting rules they change from purple to yellow, to indicate that they are showing information from a complete input (i.e. The information you provided is enough to show relevant information for you to use/interpret).

Initially you need to enter the chain length of the compound you are expecting to find. Once this has been entered, the table below that input field will display the total mass diagnostic ion for the compound of each of the included hydrocarbon classes with the given expected chain length. Meanwhile, the table on the left of the fragmentation section will also display the fragmentation ions for alkanes, alkenes, and alkadienes of the given chain length.

In the case of the methyl-branched alkanes there are two tables in the right side of the fragmentation section, one below the other. Both tables work independently, although can be complementary, and can be used for more than one compound at the same time. This is for the very probable case you will find more than one methyl-branched alkane of the same nature (i.e. mono-, di- or trimethyl) and chain length under the same peak.

The upper table indicates the methylation position on a methyl branched alkane of the given chain length, considering the fragmentation diagnostic ions you introduce in the input fields (those you see in the mass spectra). If the combination of ions you provide do not refer to a methylation position on the molecule you are specifying, the display field will retrieve "#N/A" as output. So, in case you provide two ions of two different methylation positions, or for a methylation on a methyl-branched alkane of the wrong nature (e.g. ions for one of the methylations of a dimethyl alkane in the monomethyl alkanes section).

The table below works in the other direction, it shows the ions you would expect to see in the mass spectra, for a methyl-branched alkane with a methylation on the position you specified in the input field.

Here you will find two figures illustrating the elution pattern of mono-, di-, tri- and tetramethyl-branched alkanes of the same chain length (33 carbons), which have been taken from Carlson et. al (1998) paper (The link to the paper is included in the page as source). This figures are helpful in the process of identifying methyl-branched alkanes, as you can consider the approximate region in the chromatogram where you would find a peak corresponding to a particular methyl-branched alkane. For example, you will not expect to find a 15-monomethyl alkane of a given chain length eluting before the 5-monomethyl alkane of the same chain length.

Has not been included yet.