VOC TIC Scan

Scope

A TIC (Total Ion Chromatogram) is a chromatogram created by summing up intensities of all mass spectral peaks belonging to the same scan. The TIC is compared to a GC chromatogram. Note that the TIC includes background noise as well as sample components.

This method is used to determine volatile organic compounds (VOCs) in a variety of solid waste matrices. This method is applicable to nearly all types of samples, regardless of water content, including various air sampling trapping media, ground and surface water, aqueous sludges, caustic liquors, acid liquors, waste  solvents, oily wastes, mousses, tars, fibrous wastes, polymeric emulsions, filter cakes, spent carbons, spent catalysts, soils, and sediments.

VOCs are introduced into the GC by one of the preparation methods mentioned in. The analytes may be introduced directly to a capillary column, cryofocused on a capillary pre-column before being flash evaporated to a capillary column for analysis, or desorbed from a trap and sent to an injection port operating in the split mode for injection to a capillary column. The column is temperature-programmed to separate the analytes, which are then detected with a MS interfaced to the GC. 

Analytes eluted from the capillary column are introduced into the MS via a direct connection or flow splitter. Some wide-bore capillary columns may require splitting the flow prior to the MS interface, whereas narrow-bore capillary columns may be directly interfaced to the ion source or used with a restrictor column at the MS interface. Identification of target analytes is accomplished by comparing their mass spectra and retention times (RTs) with the mass spectra and RTs of known standards for the target compounds. Quantitation is accomplished by comparing the response of a major (quantitation) ion relative to an internal standard (IS) using an appropriate calibration curve for the intended application.

 -SW-846 Online: Test Methods for Evaluating Solid Waste, Physical/Chemical Methods